[PATCH v6 00/45] Make git-am a builtin

[PATCH v6 00/45] Make git-am a builtin

[Paul Tan]

This patch series depends on pt/pull-builtin.

This is a re-roll of [v5]. The changes are as follows:

* Compacted the struct am_state declaration, so there are no ugly newlines
  between every field.

* Removed unnecessary assert()s.

* Simplified "if (x) free(x)" to just free(x)

* Only alloc memory for lock_file just before calling hold_locked_index() to
  prevent memory leaks.

* Added a patch to re-implement 271440e (git-am: make it easier after fixing up
  an unapplicable patch., 2005-10-25).

Thanks Junio and Stefan for the reviews last round. Interdiff below.

Previous versions:

[WIP v1] http://thread.gmane.org/gmane.comp.version-control.git/270048
[WIP v2] http://thread.gmane.org/gmane.comp.version-control.git/271381
[WIP v3] http://thread.gmane.org/gmane.comp.version-control.git/271967
[v4] http://thread.gmane.org/gmane.comp.version-control.git/272876
[v5] http://thread.gmane.org/gmane.comp.version-control.git/273520

git-am is a commonly used command for applying a series of patches from a
mailbox to the current branch. Currently, it is implemented by the shell script
git-am.sh. However, compared to C, shell scripts have certain deficiencies:
they need to spawn a lot of processes, introduce a lot of dependencies and
cannot take advantage of git's internal caches.

This patch series rewrites git-am.sh into C builtin/am.c, and is part of my
GSoC project to rewrite git-pull and git-am into C builtins[1].

[1] https://gist.github.com/pyokagan/1b7b0d1f4dab6ba3cef1


Paul Tan (45):
  wrapper: implement xopen()
  wrapper: implement xfopen()
  builtin-am: implement skeletal builtin am
  builtin-am: implement patch queue mechanism
  builtin-am: split out mbox/maildir patches with git-mailsplit
  builtin-am: auto-detect mbox patches
  builtin-am: extract patch and commit info with git-mailinfo
  builtin-am: apply patch with git-apply
  builtin-am: implement committing applied patch
  builtin-am: refuse to apply patches if index is dirty
  builtin-am: implement --resolved/--continue
  builtin-am: don't parse mail when resuming
  builtin-am: implement --skip
  builtin-am: implement --abort
  builtin-am: reject patches when there's a session in progress
  builtin-am: implement -q/--quiet
  builtin-am: exit with user friendly message on failure
  builtin-am: implement -s/--signoff
  cache-tree: introduce write_index_as_tree()
  builtin-am: implement --3way, am.threeWay
  builtin-am: implement --rebasing mode
  builtin-am: bypass git-mailinfo when --rebasing
  builtin-am: handle stray state directory
  builtin-am: implement -u/--utf8
  builtin-am: implement -k/--keep, --keep-non-patch
  builtin-am: implement --[no-]message-id, am.messageid
  builtin-am: support --keep-cr, am.keepcr
  builtin-am: implement --[no-]scissors
  builtin-am: pass git-apply's options to git-apply
  builtin-am: implement --ignore-date
  builtin-am: implement --committer-date-is-author-date
  builtin-am: implement -S/--gpg-sign, commit.gpgsign
  builtin-am: invoke post-rewrite hook
  builtin-am: support automatic notes copying
  builtin-am: invoke applypatch-msg hook
  builtin-am: invoke pre-applypatch hook
  builtin-am: invoke post-applypatch hook
  builtin-am: rerere support
  builtin-am: support and auto-detect StGit patches
  builtin-am: support and auto-detect StGit series files
  builtin-am: support and auto-detect mercurial patches
  builtin-am: implement -i/--interactive
  builtin-am: implement legacy -b/--binary option
  builtin-am: check for valid committer ident
  builtin-am: remove redirection to git-am.sh

 Makefile                                |    2 +-
 builtin.h                               |    1 +
 builtin/am.c                            | 2320 +++++++++++++++++++++++++++++++
 cache-tree.c                            |   29 +-
 cache-tree.h                            |    1 +
 git-am.sh => contrib/examples/git-am.sh |    0
 git-compat-util.h                       |    2 +
 git.c                                   |    1 +
 wrapper.c                               |   56 +
 9 files changed, 2399 insertions(+), 13 deletions(-)
 create mode 100644 builtin/am.c
 rename git-am.sh => contrib/examples/git-am.sh (100%)

diff --git a/builtin/am.c b/builtin/am.c
index c548129..1116304 100644
--- a/builtin/am.c
+++ b/builtin/am.c
@@ -119,38 +119,21 @@ struct am_state {
 	/* number of digits in patch filename */
 	int prec;
 
+	/* various operating modes and command line options */
 	int interactive;
-
 	int threeway;
-
 	int quiet;
-
 	int append_signoff;
-
 	int utf8;
-
-	/* one of the enum keep_type values */
-	int keep;
-
-	/* pass -m flag to git-mailinfo */
+	int keep; /* enum keep_type */
 	int message_id;
-
-	/* one of the enum scissors_type values */
-	int scissors;
-
+	int scissors; /* enum scissors_type */
 	struct argv_array git_apply_opts;
-
-	/* override error message when patch failure occurs */
 	const char *resolvemsg;
-
 	int committer_date_is_author_date;
-
 	int ignore_date;
-
 	int allow_rerere_autoupdate;
-
 	const char *sign_commit;
-
 	int rebasing;
 };
 
@@ -188,21 +171,11 @@ static void am_state_init(struct am_state *state, const char *dir)
  */
 static void am_state_release(struct am_state *state)
 {
-	if (state->dir)
-		free(state->dir);
-
-	if (state->author_name)
-		free(state->author_name);
-
-	if (state->author_email)
-		free(state->author_email);
-
-	if (state->author_date)
-		free(state->author_date);
-
-	if (state->msg)
-		free(state->msg);
-
+	free(state->dir);
+	free(state->author_name);
+	free(state->author_email);
+	free(state->author_date);
+	free(state->msg);
 	argv_array_clear(&state->git_apply_opts);
 }
 
@@ -211,8 +184,6 @@ static void am_state_release(struct am_state *state)
  */
 static inline const char *am_path(const struct am_state *state, const char *path)
 {
-	assert(state->dir);
-	assert(path);
 	return mkpath("%s/%s", state->dir, path);
 }
 
@@ -373,10 +344,6 @@ static void write_author_script(const struct am_state *state)
 {
 	struct strbuf sb = STRBUF_INIT;
 
-	assert(state->author_name);
-	assert(state->author_email);
-	assert(state->author_date);
-
 	strbuf_addstr(&sb, "GIT_AUTHOR_NAME=");
 	sq_quote_buf(&sb, state->author_name);
 	strbuf_addch(&sb, '\n');
@@ -424,8 +391,6 @@ static void write_commit_msg(const struct am_state *state)
 	int fd;
 	const char *filename = am_path(state, "final-commit");
 
-	assert(state->msg);
-
 	fd = xopen(filename, O_WRONLY | O_CREAT, 0666);
 	if (write_in_full(fd, state->msg, state->msg_len) < 0)
 		die_errno(_("could not write to %s"), filename);
@@ -1110,20 +1075,16 @@ static void am_next(struct am_state *state)
 {
 	unsigned char head[GIT_SHA1_RAWSZ];
 
-	if (state->author_name)
-		free(state->author_name);
+	free(state->author_name);
 	state->author_name = NULL;
 
-	if (state->author_email)
-		free(state->author_email);
+	free(state->author_email);
 	state->author_email = NULL;
 
-	if (state->author_date)
-		free(state->author_date);
+	free(state->author_date);
 	state->author_date = NULL;
 
-	if (state->msg)
-		free(state->msg);
+	free(state->msg);
 	state->msg = NULL;
 	state->msg_len = 0;
 
@@ -1160,13 +1121,12 @@ static const char *msgnum(const struct am_state *state)
  */
 static void refresh_and_write_cache(void)
 {
-	static struct lock_file lock_file;
+	struct lock_file *lock_file = xcalloc(1, sizeof(struct lock_file));
 
-	hold_locked_index(&lock_file, 1);
+	hold_locked_index(lock_file, 1);
 	refresh_cache(REFRESH_QUIET);
-	if (write_locked_index(&the_index, &lock_file, COMMIT_LOCK))
+	if (write_locked_index(&the_index, lock_file, COMMIT_LOCK))
 		die(_("unable to write index file"));
-	rollback_lock_file(&lock_file);
 }
 
 /**
@@ -1714,6 +1674,21 @@ static void do_commit(const struct am_state *state)
 }
 
 /**
+ * Validates the am_state for resuming -- the "msg" and authorship fields must
+ * be filled up.
+ */
+static void validate_resume_state(const struct am_state *state)
+{
+	if (!state->msg)
+		die(_("cannot resume: %s does not exist."),
+			am_path(state, "final-commit"));
+
+	if (!state->author_name || !state->author_email || !state->author_date)
+		die(_("cannot resume: %s does not exist."),
+			am_path(state, "author-script"));
+}
+
+/**
  * Interactively prompt the user on whether the current patch should be
  * applied.
  *
@@ -1774,8 +1749,12 @@ static int do_interactive(struct am_state *state)
 
 /**
  * Applies all queued mail.
+ *
+ * If `resume` is true, we are "resuming". The "msg" and authorship fields, as
+ * well as the state directory's "patch" file is used as-is for applying the
+ * patch and committing it.
  */
-static void am_run(struct am_state *state)
+static void am_run(struct am_state *state, int resume)
 {
 	const char *argv_gc_auto[] = {"gc", "--auto", NULL};
 	struct strbuf sb = STRBUF_INIT;
@@ -1793,21 +1772,28 @@ static void am_run(struct am_state *state)
 
 	while (state->cur <= state->last) {
 		const char *mail = am_path(state, msgnum(state));
-		int apply_status, skip;
+		int apply_status;
 
 		if (!file_exists(mail))
 			goto next;
 
-		if (state->rebasing)
-			skip = parse_mail_rebase(state, mail);
-		else
-			skip = parse_mail(state, mail);
+		if (resume) {
+			validate_resume_state(state);
+			resume = 0;
+		} else {
+			int skip;
 
-		if (skip)
-			goto next; /* mail should be skipped */
+			if (state->rebasing)
+				skip = parse_mail_rebase(state, mail);
+			else
+				skip = parse_mail(state, mail);
+
+			if (skip)
+				goto next; /* mail should be skipped */
 
-		write_author_script(state);
-		write_commit_msg(state);
+			write_author_script(state);
+			write_commit_msg(state);
+		}
 
 		if (state->interactive && do_interactive(state))
 			goto next;
@@ -1880,13 +1866,7 @@ next:
  */
 static void am_resolve(struct am_state *state)
 {
-	if (!state->msg)
-		die(_("cannot resume: %s does not exist."),
-			am_path(state, "final-commit"));
-
-	if (!state->author_name || !state->author_email || !state->author_date)
-		die(_("cannot resume: %s does not exist."),
-			am_path(state, "author-script"));
+	validate_resume_state(state);
 
 	say(state, stdout, _("Applying: %.*s"), linelen(state->msg), state->msg);
 
@@ -1915,7 +1895,7 @@ static void am_resolve(struct am_state *state)
 
 next:
 	am_next(state);
-	am_run(state);
+	am_run(state, 0);
 }
 
 /**
@@ -1925,13 +1905,14 @@ next:
  */
 static int fast_forward_to(struct tree *head, struct tree *remote, int reset)
 {
-	struct lock_file *lock_file = xcalloc(1, sizeof(struct lock_file));
+	struct lock_file *lock_file;
 	struct unpack_trees_options opts;
 	struct tree_desc t[2];
 
 	if (parse_tree(head) || parse_tree(remote))
 		return -1;
 
+	lock_file = xcalloc(1, sizeof(struct lock_file));
 	hold_locked_index(lock_file, 1);
 
 	refresh_cache(REFRESH_QUIET);
@@ -1964,7 +1945,7 @@ static int fast_forward_to(struct tree *head, struct tree *remote, int reset)
  */
 static int clean_index(const unsigned char *head, const unsigned char *remote)
 {
-	struct lock_file *lock_file = xcalloc(1, sizeof(struct lock_file));
+	struct lock_file *lock_file;
 	struct tree *head_tree, *remote_tree, *index_tree;
 	unsigned char index[GIT_SHA1_RAWSZ];
 	struct pathspec pathspec;
@@ -1994,6 +1975,7 @@ static int clean_index(const unsigned char *head, const unsigned char *remote)
 
 	memset(&pathspec, 0, sizeof(pathspec));
 
+	lock_file = xcalloc(1, sizeof(struct lock_file));
 	hold_locked_index(lock_file, 1);
 
 	if (read_tree(remote_tree, 0, &pathspec)) {
@@ -2040,7 +2022,7 @@ static void am_skip(struct am_state *state)
 		die(_("failed to clean index"));
 
 	am_next(state);
-	am_run(state);
+	am_run(state, 0);
 }
 
 /**
@@ -2136,6 +2118,7 @@ static int parse_opt_patchformat(const struct option *opt, const char *arg, int
 
 enum resume_mode {
 	RESUME_FALSE = 0,
+	RESUME_APPLY,
 	RESUME_RESOLVED,
 	RESUME_SKIP,
 	RESUME_ABORT
@@ -2271,6 +2254,9 @@ int cmd_am(int argc, const char **argv, const char *prefix)
 			die(_("previous rebase directory %s still exists but mbox given."),
 				state.dir);
 
+		if (resume == RESUME_FALSE)
+			resume = RESUME_APPLY;
+
 		am_load(&state);
 	} else {
 		struct argv_array paths = ARGV_ARRAY_INIT;
@@ -2310,7 +2296,10 @@ int cmd_am(int argc, const char **argv, const char *prefix)
 
 	switch (resume) {
 	case RESUME_FALSE:
-		am_run(&state);
+		am_run(&state, 0);
+		break;
+	case RESUME_APPLY:
+		am_run(&state, 1);
 		break;
 	case RESUME_RESOLVED:
 		am_resolve(&state);

-- 
2.5.0.rc2.110.gb39b692

[PATCH v6 01/45] wrapper: implement xopen()

[Paul Tan]

A common usage pattern of open() is to check if it was successful, and
die() if it was not:

	int fd = open(path, O_WRONLY | O_CREAT, 0777);
	if (fd < 0)
		die_errno(_("Could not open '%s' for writing."), path);

Implement a wrapper function xopen() that does the above so that we can
save a few lines of code, and make the die() messages consistent.

Helped-by: Torsten Bögershausen <tboegi@web.de>
Helped-by: Jeff King <peff@peff.net>
Helped-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Helped-by: Junio C Hamano <gitster@pobox.com>
Signed-off-by: Paul Tan <pyokagan@gmail.com>
---
 git-compat-util.h |  1 +
 wrapper.c         | 35 +++++++++++++++++++++++++++++++++++
 2 files changed, 36 insertions(+)

diff --git a/git-compat-util.h b/git-compat-util.h
index c6d391f..e168dfd 100644
--- a/git-compat-util.h
+++ b/git-compat-util.h
@@ -717,6 +717,7 @@ extern void *xrealloc(void *ptr, size_t size);
 extern void *xcalloc(size_t nmemb, size_t size);
 extern void *xmmap(void *start, size_t length, int prot, int flags, int fd, off_t offset);
 extern void *xmmap_gently(void *start, size_t length, int prot, int flags, int fd, off_t offset);
+extern int xopen(const char *path, int flags, ...);
 extern ssize_t xread(int fd, void *buf, size_t len);
 extern ssize_t xwrite(int fd, const void *buf, size_t len);
 extern ssize_t xpread(int fd, void *buf, size_t len, off_t offset);
diff --git a/wrapper.c b/wrapper.c
index ff49807..0a4502d 100644
--- a/wrapper.c
+++ b/wrapper.c
@@ -189,6 +189,41 @@ void *xcalloc(size_t nmemb, size_t size)
 # endif
 #endif
 
+/**
+ * xopen() is the same as open(), but it die()s if the open() fails.
+ */
+int xopen(const char *path, int oflag, ...)
+{
+	mode_t mode = 0;
+	va_list ap;
+
+	/*
+	 * va_arg() will have undefined behavior if the specified type is not
+	 * compatible with the argument type. Since integers are promoted to
+	 * ints, we fetch the next argument as an int, and then cast it to a
+	 * mode_t to avoid undefined behavior.
+	 */
+	va_start(ap, oflag);
+	if (oflag & O_CREAT)
+		mode = va_arg(ap, int);
+	va_end(ap);
+
+	for (;;) {
+		int fd = open(path, oflag, mode);
+		if (fd >= 0)
+			return fd;
+		if (errno == EINTR)
+			continue;
+
+		if ((oflag & O_RDWR) == O_RDWR)
+			die_errno(_("could not open '%s' for reading and writing"), path);
+		else if ((oflag & O_WRONLY) == O_WRONLY)
+			die_errno(_("could not open '%s' for writing"), path);
+		else
+			die_errno(_("could not open '%s' for reading"), path);
+	}
+}
+
 /*
  * xread() is the same a read(), but it automatically restarts read()
  * operations with a recoverable error (EAGAIN and EINTR). xread()
-- 
2.5.0.rc2.110.gb39b692

[PATCH v6 02/45] wrapper: implement xfopen()

[Paul Tan]

A common usage pattern of fopen() is to check if it succeeded, and die()
if it failed:

	FILE *fp = fopen(path, "w");
	if (!fp)
		die_errno(_("could not open '%s' for writing"), path);

Implement a wrapper function xfopen() for the above, so that we can save
a few lines of code and make the die() messages consistent.

Helped-by: Jeff King <peff@peff.net>
Helped-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Helped-by: Junio C Hamano <gitster@pobox.com>
Signed-off-by: Paul Tan <pyokagan@gmail.com>
---
 git-compat-util.h |  1 +
 wrapper.c         | 21 +++++++++++++++++++++
 2 files changed, 22 insertions(+)

diff --git a/git-compat-util.h b/git-compat-util.h
index e168dfd..392da79 100644
--- a/git-compat-util.h
+++ b/git-compat-util.h
@@ -722,6 +722,7 @@ extern ssize_t xread(int fd, void *buf, size_t len);
 extern ssize_t xwrite(int fd, const void *buf, size_t len);
 extern ssize_t xpread(int fd, void *buf, size_t len, off_t offset);
 extern int xdup(int fd);
+extern FILE *xfopen(const char *path, const char *mode);
 extern FILE *xfdopen(int fd, const char *mode);
 extern int xmkstemp(char *template);
 extern int xmkstemp_mode(char *template, int mode);
diff --git a/wrapper.c b/wrapper.c
index 0a4502d..e451463 100644
--- a/wrapper.c
+++ b/wrapper.c
@@ -346,6 +346,27 @@ int xdup(int fd)
 	return ret;
 }
 
+/**
+ * xfopen() is the same as fopen(), but it die()s if the fopen() fails.
+ */
+FILE *xfopen(const char *path, const char *mode)
+{
+	for (;;) {
+		FILE *fp = fopen(path, mode);
+		if (fp)
+			return fp;
+		if (errno == EINTR)
+			continue;
+
+		if (*mode && mode[1] == '+')
+			die_errno(_("could not open '%s' for reading and writing"), path);
+		else if (*mode == 'w' || *mode == 'a')
+			die_errno(_("could not open '%s' for writing"), path);
+		else
+			die_errno(_("could not open '%s' for reading"), path);
+	}
+}
+
 FILE *xfdopen(int fd, const char *mode)
 {
 	FILE *stream = fdopen(fd, mode);
-- 
2.5.0.rc2.110.gb39b692

[PATCH v6 03/45] builtin-am: implement skeletal builtin am

[Paul Tan]

For the purpose of rewriting git-am.sh into a C builtin, implement a
skeletal builtin/am.c that redirects to $GIT_EXEC_PATH/git-am if the
environment variable _GIT_USE_BUILTIN_AM is not defined. Since in the
Makefile git-am.sh takes precedence over builtin/am.c,
$GIT_EXEC_PATH/git-am will contain the shell script git-am.sh, and thus
this allows us to fall back on the functional git-am.sh when running the
test suite for tests that depend on a working git-am implementation.

Since git-am.sh cannot handle any environment modifications by
setup_git_directory(), "am" is declared with no setup flags in git.c. On
the other hand, to re-implement git-am.sh in builtin/am.c, we need to
run all the git dir and work tree setup logic that git.c typically does
for us. As such, we work around this temporarily by copying the logic in
git.c's run_builtin(), which is roughly:

	prefix = setup_git_directory();
	trace_repo_setup(prefix);
	setup_work_tree();

This redirection should be removed when all the features of git-am.sh
have been re-implemented in builtin/am.c.

Helped-by: Junio C Hamano <gitster@pobox.com>
Signed-off-by: Paul Tan <pyokagan@gmail.com>
---
 Makefile     |  1 +
 builtin.h    |  1 +
 builtin/am.c | 29 +++++++++++++++++++++++++++++
 git.c        |  6 ++++++
 4 files changed, 37 insertions(+)
 create mode 100644 builtin/am.c

diff --git a/Makefile b/Makefile
index c6c28bc..f88642a 100644
--- a/Makefile
+++ b/Makefile
@@ -812,6 +812,7 @@ LIB_OBJS += xdiff-interface.o
 LIB_OBJS += zlib.o
 
 BUILTIN_OBJS += builtin/add.o
+BUILTIN_OBJS += builtin/am.o
 BUILTIN_OBJS += builtin/annotate.o
 BUILTIN_OBJS += builtin/apply.o
 BUILTIN_OBJS += builtin/archive.o
diff --git a/builtin.h b/builtin.h
index 839483d..79aaf0a 100644
--- a/builtin.h
+++ b/builtin.h
@@ -30,6 +30,7 @@ extern int textconv_object(const char *path, unsigned mode, const unsigned char
 extern int is_builtin(const char *s);
 
 extern int cmd_add(int argc, const char **argv, const char *prefix);
+extern int cmd_am(int argc, const char **argv, const char *prefix);
 extern int cmd_annotate(int argc, const char **argv, const char *prefix);
 extern int cmd_apply(int argc, const char **argv, const char *prefix);
 extern int cmd_archive(int argc, const char **argv, const char *prefix);
diff --git a/builtin/am.c b/builtin/am.c
new file mode 100644
index 0000000..fd32caf
--- /dev/null
+++ b/builtin/am.c
@@ -0,0 +1,29 @@
+/*
+ * Builtin "git am"
+ *
+ * Based on git-am.sh by Junio C Hamano.
+ */
+#include "cache.h"
+#include "builtin.h"
+#include "exec_cmd.h"
+
+int cmd_am(int argc, const char **argv, const char *prefix)
+{
+
+	/*
+	 * NEEDSWORK: Once all the features of git-am.sh have been
+	 * re-implemented in builtin/am.c, this preamble can be removed.
+	 */
+	if (!getenv("_GIT_USE_BUILTIN_AM")) {
+		const char *path = mkpath("%s/git-am", git_exec_path());
+
+		if (sane_execvp(path, (char **)argv) < 0)
+			die_errno("could not exec %s", path);
+	} else {
+		prefix = setup_git_directory();
+		trace_repo_setup(prefix);
+		setup_work_tree();
+	}
+
+	return 0;
+}
diff --git a/git.c b/git.c
index 55c327c..38d9ad5 100644
--- a/git.c
+++ b/git.c
@@ -370,6 +370,12 @@ static int run_builtin(struct cmd_struct *p, int argc, const char **argv)
 
 static struct cmd_struct commands[] = {
 	{ "add", cmd_add, RUN_SETUP | NEED_WORK_TREE },
+	/*
+	 * NEEDSWORK: Once the redirection to git-am.sh in builtin/am.c has
+	 * been removed, this entry should be changed to
+	 * RUN_SETUP | NEED_WORK_TREE
+	 */
+	{ "am", cmd_am },
 	{ "annotate", cmd_annotate, RUN_SETUP },
 	{ "apply", cmd_apply, RUN_SETUP_GENTLY },
 	{ "archive", cmd_archive },
-- 
2.5.0.rc2.110.gb39b692

[PATCH v6 04/45] builtin-am: implement patch queue mechanism

[Paul Tan]

git-am applies a series of patches. If the process terminates
abnormally, we want to be able to resume applying the series of patches.
This requires the session state to be saved in a persistent location.

Implement the mechanism of a "patch queue", represented by 2 integers --
the index of the current patch we are applying and the index of the last
patch, as well as its lifecycle through the following functions:

* am_setup(), which will set up the state directory
  $GIT_DIR/rebase-apply. As such, even if the process exits abnormally,
  the last-known state will still persist.

* am_load(), which is called if there is an am session in
  progress, to load the last known state from the state directory so we
  can resume applying patches.

* am_run(), which will do the actual patch application. After applying a
  patch, it calls am_next() to increment the current patch index. The
  logic for applying and committing a patch is not implemented yet.

* am_destroy(), which is finally called when we successfully applied all
  the patches in the queue, to clean up by removing the state directory
  and its contents.

Helped-by: Junio C Hamano <gitster@pobox.com>
Helped-by: Stefan Beller <sbeller@google.com>
Helped-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Paul Tan <pyokagan@gmail.com>
---
 builtin/am.c | 177 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 177 insertions(+)

diff --git a/builtin/am.c b/builtin/am.c
index fd32caf..ac172c4 100644
--- a/builtin/am.c
+++ b/builtin/am.c
@@ -6,9 +6,171 @@
 #include "cache.h"
 #include "builtin.h"
 #include "exec_cmd.h"
+#include "parse-options.h"
+#include "dir.h"
+
+struct am_state {
+	/* state directory path */
+	char *dir;
+
+	/* current and last patch numbers, 1-indexed */
+	int cur;
+	int last;
+};
+
+/**
+ * Initializes am_state with the default values. The state directory is set to
+ * dir.
+ */
+static void am_state_init(struct am_state *state, const char *dir)
+{
+	memset(state, 0, sizeof(*state));
+
+	assert(dir);
+	state->dir = xstrdup(dir);
+}
+
+/**
+ * Releases memory allocated by an am_state.
+ */
+static void am_state_release(struct am_state *state)
+{
+	free(state->dir);
+}
+
+/**
+ * Returns path relative to the am_state directory.
+ */
+static inline const char *am_path(const struct am_state *state, const char *path)
+{
+	return mkpath("%s/%s", state->dir, path);
+}
+
+/**
+ * Returns 1 if there is an am session in progress, 0 otherwise.
+ */
+static int am_in_progress(const struct am_state *state)
+{
+	struct stat st;
+
+	if (lstat(state->dir, &st) < 0 || !S_ISDIR(st.st_mode))
+		return 0;
+	if (lstat(am_path(state, "last"), &st) || !S_ISREG(st.st_mode))
+		return 0;
+	if (lstat(am_path(state, "next"), &st) || !S_ISREG(st.st_mode))
+		return 0;
+	return 1;
+}
+
+/**
+ * Reads the contents of `file` in the `state` directory into `sb`. Returns the
+ * number of bytes read on success, -1 if the file does not exist. If `trim` is
+ * set, trailing whitespace will be removed.
+ */
+static int read_state_file(struct strbuf *sb, const struct am_state *state,
+			const char *file, int trim)
+{
+	strbuf_reset(sb);
+
+	if (strbuf_read_file(sb, am_path(state, file), 0) >= 0) {
+		if (trim)
+			strbuf_trim(sb);
+
+		return sb->len;
+	}
+
+	if (errno == ENOENT)
+		return -1;
+
+	die_errno(_("could not read '%s'"), am_path(state, file));
+}
+
+/**
+ * Loads state from disk.
+ */
+static void am_load(struct am_state *state)
+{
+	struct strbuf sb = STRBUF_INIT;
+
+	if (read_state_file(&sb, state, "next", 1) < 0)
+		die("BUG: state file 'next' does not exist");
+	state->cur = strtol(sb.buf, NULL, 10);
+
+	if (read_state_file(&sb, state, "last", 1) < 0)
+		die("BUG: state file 'last' does not exist");
+	state->last = strtol(sb.buf, NULL, 10);
+
+	strbuf_release(&sb);
+}
+
+/**
+ * Removes the am_state directory, forcefully terminating the current am
+ * session.
+ */
+static void am_destroy(const struct am_state *state)
+{
+	struct strbuf sb = STRBUF_INIT;
+
+	strbuf_addstr(&sb, state->dir);
+	remove_dir_recursively(&sb, 0);
+	strbuf_release(&sb);
+}
+
+/**
+ * Setup a new am session for applying patches
+ */
+static void am_setup(struct am_state *state)
+{
+	if (mkdir(state->dir, 0777) < 0 && errno != EEXIST)
+		die_errno(_("failed to create directory '%s'"), state->dir);
+
+	/*
+	 * NOTE: Since the "next" and "last" files determine if an am_state
+	 * session is in progress, they should be written last.
+	 */
+
+	write_file(am_path(state, "next"), 1, "%d", state->cur);
+
+	write_file(am_path(state, "last"), 1, "%d", state->last);
+}
+
+/**
+ * Increments the patch pointer, and cleans am_state for the application of the
+ * next patch.
+ */
+static void am_next(struct am_state *state)
+{
+	state->cur++;
+	write_file(am_path(state, "next"), 1, "%d", state->cur);
+}
+
+/**
+ * Applies all queued mail.
+ */
+static void am_run(struct am_state *state)
+{
+	while (state->cur <= state->last) {
+
+		/* NEEDSWORK: Patch application not implemented yet */
+
+		am_next(state);
+	}
+
+	am_destroy(state);
+}
 
 int cmd_am(int argc, const char **argv, const char *prefix)
 {
+	struct am_state state;
+
+	const char * const usage[] = {
+		N_("git am [options] [(<mbox>|<Maildir>)...]"),
+		NULL
+	};
+
+	struct option options[] = {
+		OPT_END()
+	};
 
 	/*
 	 * NEEDSWORK: Once all the features of git-am.sh have been
@@ -25,5 +187,20 @@ int cmd_am(int argc, const char **argv, const char *prefix)
 		setup_work_tree();
 	}
 
+	git_config(git_default_config, NULL);
+
+	am_state_init(&state, git_path("rebase-apply"));
+
+	argc = parse_options(argc, argv, prefix, options, usage, 0);
+
+	if (am_in_progress(&state))
+		am_load(&state);
+	else
+		am_setup(&state);
+
+	am_run(&state);
+
+	am_state_release(&state);
+
 	return 0;
 }
-- 
2.5.0.rc2.110.gb39b692

[PATCH v6 05/45] builtin-am: split out mbox/maildir patches with git-mailsplit

[Paul Tan]

git-am.sh supports mbox, stgit and mercurial patches. Re-implement
support for splitting out mbox/maildirs using git-mailsplit, while also
implementing the framework required to support other patch formats in
the future.

Re-implement support for the --patch-format option (since a5a6755
(git-am foreign patch support: introduce patch_format, 2009-05-27)) to
allow the user to choose between the different patch formats.

Helped-by: Junio C Hamano <gitster@pobox.com>
Signed-off-by: Paul Tan <pyokagan@gmail.com>
---
 builtin/am.c | 107 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++--
 1 file changed, 104 insertions(+), 3 deletions(-)

diff --git a/builtin/am.c b/builtin/am.c
index ac172c4..5f3c131 100644
--- a/builtin/am.c
+++ b/builtin/am.c
@@ -8,6 +8,12 @@
 #include "exec_cmd.h"
 #include "parse-options.h"
 #include "dir.h"
+#include "run-command.h"
+
+enum patch_format {
+	PATCH_FORMAT_UNKNOWN = 0,
+	PATCH_FORMAT_MBOX
+};
 
 struct am_state {
 	/* state directory path */
@@ -16,6 +22,9 @@ struct am_state {
 	/* current and last patch numbers, 1-indexed */
 	int cur;
 	int last;
+
+	/* number of digits in patch filename */
+	int prec;
 };
 
 /**
@@ -28,6 +37,8 @@ static void am_state_init(struct am_state *state, const char *dir)
 
 	assert(dir);
 	state->dir = xstrdup(dir);
+
+	state->prec = 4;
 }
 
 /**
@@ -117,13 +128,71 @@ static void am_destroy(const struct am_state *state)
 }
 
 /**
+ * Splits out individual email patches from `paths`, where each path is either
+ * a mbox file or a Maildir. Returns 0 on success, -1 on failure.
+ */
+static int split_mail_mbox(struct am_state *state, const char **paths)
+{
+	struct child_process cp = CHILD_PROCESS_INIT;
+	struct strbuf last = STRBUF_INIT;
+
+	cp.git_cmd = 1;
+	argv_array_push(&cp.args, "mailsplit");
+	argv_array_pushf(&cp.args, "-d%d", state->prec);
+	argv_array_pushf(&cp.args, "-o%s", state->dir);
+	argv_array_push(&cp.args, "-b");
+	argv_array_push(&cp.args, "--");
+	argv_array_pushv(&cp.args, paths);
+
+	if (capture_command(&cp, &last, 8))
+		return -1;
+
+	state->cur = 1;
+	state->last = strtol(last.buf, NULL, 10);
+
+	return 0;
+}
+
+/**
+ * Splits a list of files/directories into individual email patches. Each path
+ * in `paths` must be a file/directory that is formatted according to
+ * `patch_format`.
+ *
+ * Once split out, the individual email patches will be stored in the state
+ * directory, with each patch's filename being its index, padded to state->prec
+ * digits.
+ *
+ * state->cur will be set to the index of the first mail, and state->last will
+ * be set to the index of the last mail.
+ *
+ * Returns 0 on success, -1 on failure.
+ */
+static int split_mail(struct am_state *state, enum patch_format patch_format,
+			const char **paths)
+{
+	switch (patch_format) {
+	case PATCH_FORMAT_MBOX:
+		return split_mail_mbox(state, paths);
+	default:
+		die("BUG: invalid patch_format");
+	}
+	return -1;
+}
+
+/**
  * Setup a new am session for applying patches
  */
-static void am_setup(struct am_state *state)
+static void am_setup(struct am_state *state, enum patch_format patch_format,
+			const char **paths)
 {
 	if (mkdir(state->dir, 0777) < 0 && errno != EEXIST)
 		die_errno(_("failed to create directory '%s'"), state->dir);
 
+	if (split_mail(state, patch_format, paths) < 0) {
+		am_destroy(state);
+		die(_("Failed to split patches."));
+	}
+
 	/*
 	 * NOTE: Since the "next" and "last" files determine if an am_state
 	 * session is in progress, they should be written last.
@@ -159,9 +228,25 @@ static void am_run(struct am_state *state)
 	am_destroy(state);
 }
 
+/**
+ * parse_options() callback that validates and sets opt->value to the
+ * PATCH_FORMAT_* enum value corresponding to `arg`.
+ */
+static int parse_opt_patchformat(const struct option *opt, const char *arg, int unset)
+{
+	int *opt_value = opt->value;
+
+	if (!strcmp(arg, "mbox"))
+		*opt_value = PATCH_FORMAT_MBOX;
+	else
+		return error(_("Invalid value for --patch-format: %s"), arg);
+	return 0;
+}
+
 int cmd_am(int argc, const char **argv, const char *prefix)
 {
 	struct am_state state;
+	int patch_format = PATCH_FORMAT_UNKNOWN;
 
 	const char * const usage[] = {
 		N_("git am [options] [(<mbox>|<Maildir>)...]"),
@@ -169,6 +254,9 @@ int cmd_am(int argc, const char **argv, const char *prefix)
 	};
 
 	struct option options[] = {
+		OPT_CALLBACK(0, "patch-format", &patch_format, N_("format"),
+			N_("format the patch(es) are in"),
+			parse_opt_patchformat),
 		OPT_END()
 	};
 
@@ -195,8 +283,21 @@ int cmd_am(int argc, const char **argv, const char *prefix)
 
 	if (am_in_progress(&state))
 		am_load(&state);
-	else
-		am_setup(&state);
+	else {
+		struct argv_array paths = ARGV_ARRAY_INIT;
+		int i;
+
+		for (i = 0; i < argc; i++) {
+			if (is_absolute_path(argv[i]) || !prefix)
+				argv_array_push(&paths, argv[i]);
+			else
+				argv_array_push(&paths, mkpath("%s/%s", prefix, argv[i]));
+		}
+
+		am_setup(&state, patch_format, paths.argv);
+
+		argv_array_clear(&paths);
+	}
 
 	am_run(&state);
 
-- 
2.5.0.rc2.110.gb39b692

[PATCH v6 06/45] builtin-am: auto-detect mbox patches

[Paul Tan]

Since 15ced75 (git-am foreign patch support: autodetect some patch
formats, 2009-05-27), git-am.sh is able to autodetect mbox, stgit and
mercurial patches through heuristics.

Re-implement support for autodetecting mbox/maildir files in
builtin/am.c.

RFC 2822 requires that lines are terminated by "\r\n". To support this,
implement strbuf_getline_crlf(), which will remove both '\n' and "\r\n"
from the end of the line.

Helped-by: Junio C Hamano <gitster@pobox.com>
Helped-by: Eric Sunshine <sunshine@sunshineco.com>
Helped-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Paul Tan <pyokagan@gmail.com>
---
 builtin/am.c | 109 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 109 insertions(+)

diff --git a/builtin/am.c b/builtin/am.c
index 5f3c131..c12566a 100644
--- a/builtin/am.c
+++ b/builtin/am.c
@@ -10,6 +10,21 @@
 #include "dir.h"
 #include "run-command.h"
 
+/**
+ * Like strbuf_getline(), but treats both '\n' and "\r\n" as line terminators.
+ */
+static int strbuf_getline_crlf(struct strbuf *sb, FILE *fp)
+{
+	if (strbuf_getwholeline(sb, fp, '\n'))
+		return EOF;
+	if (sb->buf[sb->len - 1] == '\n') {
+		strbuf_setlen(sb, sb->len - 1);
+		if (sb->len > 0 && sb->buf[sb->len - 1] == '\r')
+			strbuf_setlen(sb, sb->len - 1);
+	}
+	return 0;
+}
+
 enum patch_format {
 	PATCH_FORMAT_UNKNOWN = 0,
 	PATCH_FORMAT_MBOX
@@ -128,6 +143,92 @@ static void am_destroy(const struct am_state *state)
 }
 
 /**
+ * Determines if the file looks like a piece of RFC2822 mail by grabbing all
+ * non-indented lines and checking if they look like they begin with valid
+ * header field names.
+ *
+ * Returns 1 if the file looks like a piece of mail, 0 otherwise.
+ */
+static int is_mail(FILE *fp)
+{
+	const char *header_regex = "^[!-9;-~]+:";
+	struct strbuf sb = STRBUF_INIT;
+	regex_t regex;
+	int ret = 1;
+
+	if (fseek(fp, 0L, SEEK_SET))
+		die_errno(_("fseek failed"));
+
+	if (regcomp(&regex, header_regex, REG_NOSUB | REG_EXTENDED))
+		die("invalid pattern: %s", header_regex);
+
+	while (!strbuf_getline_crlf(&sb, fp)) {
+		if (!sb.len)
+			break; /* End of header */
+
+		/* Ignore indented folded lines */
+		if (*sb.buf == '\t' || *sb.buf == ' ')
+			continue;
+
+		/* It's a header if it matches header_regex */
+		if (regexec(&regex, sb.buf, 0, NULL, 0)) {
+			ret = 0;
+			goto done;
+		}
+	}
+
+done:
+	regfree(&regex);
+	strbuf_release(&sb);
+	return ret;
+}
+
+/**
+ * Attempts to detect the patch_format of the patches contained in `paths`,
+ * returning the PATCH_FORMAT_* enum value. Returns PATCH_FORMAT_UNKNOWN if
+ * detection fails.
+ */
+static int detect_patch_format(const char **paths)
+{
+	enum patch_format ret = PATCH_FORMAT_UNKNOWN;
+	struct strbuf l1 = STRBUF_INIT;
+	FILE *fp;
+
+	/*
+	 * We default to mbox format if input is from stdin and for directories
+	 */
+	if (!*paths || !strcmp(*paths, "-") || is_directory(*paths))
+		return PATCH_FORMAT_MBOX;
+
+	/*
+	 * Otherwise, check the first few lines of the first patch, starting
+	 * from the first non-blank line, to try to detect its format.
+	 */
+
+	fp = xfopen(*paths, "r");
+
+	while (!strbuf_getline_crlf(&l1, fp)) {
+		if (l1.len)
+			break;
+	}
+
+	if (starts_with(l1.buf, "From ") || starts_with(l1.buf, "From: ")) {
+		ret = PATCH_FORMAT_MBOX;
+		goto done;
+	}
+
+	if (l1.len && is_mail(fp)) {
+		ret = PATCH_FORMAT_MBOX;
+		goto done;
+	}
+
+done:
+	fclose(fp);
+	strbuf_release(&l1);
+	return ret;
+}
+
+/**
  * Splits out individual email patches from `paths`, where each path is either
  * a mbox file or a Maildir. Returns 0 on success, -1 on failure.
  */
@@ -185,6 +286,14 @@ static int split_mail(struct am_state *state, enum patch_format patch_format,
 static void am_setup(struct am_state *state, enum patch_format patch_format,
 			const char **paths)
 {
+	if (!patch_format)
+		patch_format = detect_patch_format(paths);
+
+	if (!patch_format) {
+		fprintf_ln(stderr, _("Patch format detection failed."));
+		exit(128);
+	}
+
 	if (mkdir(state->dir, 0777) < 0 && errno != EEXIST)
 		die_errno(_("failed to create directory '%s'"), state->dir);
 
-- 
2.5.0.rc2.110.gb39b692

[PATCH v6 07/45] builtin-am: extract patch and commit info with git-mailinfo

[Paul Tan]

For the purpose of applying the patch and committing the results,
implement extracting the patch data, commit message and authorship from
an e-mail message using git-mailinfo.

git-mailinfo is run as a separate process, but ideally in the future,
we should be be able to access its functionality directly without
spawning a new process.

Helped-by: Junio C Hamano <gitster@pobox.com>
Helped-by: Jeff King <peff@peff.net>
Helped-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Paul Tan <pyokagan@gmail.com>
---
 builtin/am.c | 317 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 317 insertions(+)

diff --git a/builtin/am.c b/builtin/am.c
index c12566a..63f0fa4 100644
--- a/builtin/am.c
+++ b/builtin/am.c
@@ -9,6 +9,23 @@
 #include "parse-options.h"
 #include "dir.h"
 #include "run-command.h"
+#include "quote.h"
+
+/**
+ * Returns 1 if the file is empty or does not exist, 0 otherwise.
+ */
+static int is_empty_file(const char *filename)
+{
+	struct stat st;
+
+	if (stat(filename, &st) < 0) {
+		if (errno == ENOENT)
+			return 1;
+		die_errno(_("could not stat %s"), filename);
+	}
+
+	return !st.st_size;
+}
 
 /**
  * Like strbuf_getline(), but treats both '\n' and "\r\n" as line terminators.
@@ -38,6 +55,13 @@ struct am_state {
 	int cur;
 	int last;
 
+	/* commit metadata and message */
+	char *author_name;
+	char *author_email;
+	char *author_date;
+	char *msg;
+	size_t msg_len;
+
 	/* number of digits in patch filename */
 	int prec;
 };
@@ -62,6 +86,10 @@ static void am_state_init(struct am_state *state, const char *dir)
 static void am_state_release(struct am_state *state)
 {
 	free(state->dir);
+	free(state->author_name);
+	free(state->author_email);
+	free(state->author_date);
+	free(state->msg);
 }
 
 /**
@@ -112,6 +140,161 @@ static int read_state_file(struct strbuf *sb, const struct am_state *state,
 }
 
 /**
+ * Reads a KEY=VALUE shell variable assignment from `fp`, returning the VALUE
+ * as a newly-allocated string. VALUE must be a quoted string, and the KEY must
+ * match `key`. Returns NULL on failure.
+ *
+ * This is used by read_author_script() to read the GIT_AUTHOR_* variables from
+ * the author-script.
+ */
+static char *read_shell_var(FILE *fp, const char *key)
+{
+	struct strbuf sb = STRBUF_INIT;
+	const char *str;
+
+	if (strbuf_getline(&sb, fp, '\n'))
+		goto fail;
+
+	if (!skip_prefix(sb.buf, key, &str))
+		goto fail;
+
+	if (!skip_prefix(str, "=", &str))
+		goto fail;
+
+	strbuf_remove(&sb, 0, str - sb.buf);
+
+	str = sq_dequote(sb.buf);
+	if (!str)
+		goto fail;
+
+	return strbuf_detach(&sb, NULL);
+
+fail:
+	strbuf_release(&sb);
+	return NULL;
+}
+
+/**
+ * Reads and parses the state directory's "author-script" file, and sets
+ * state->author_name, state->author_email and state->author_date accordingly.
+ * Returns 0 on success, -1 if the file could not be parsed.
+ *
+ * The author script is of the format:
+ *
+ *	GIT_AUTHOR_NAME='$author_name'
+ *	GIT_AUTHOR_EMAIL='$author_email'
+ *	GIT_AUTHOR_DATE='$author_date'
+ *
+ * where $author_name, $author_email and $author_date are quoted. We are strict
+ * with our parsing, as the file was meant to be eval'd in the old git-am.sh
+ * script, and thus if the file differs from what this function expects, it is
+ * better to bail out than to do something that the user does not expect.
+ */
+static int read_author_script(struct am_state *state)
+{
+	const char *filename = am_path(state, "author-script");
+	FILE *fp;
+
+	assert(!state->author_name);
+	assert(!state->author_email);
+	assert(!state->author_date);
+
+	fp = fopen(filename, "r");
+	if (!fp) {
+		if (errno == ENOENT)
+			return 0;
+		die_errno(_("could not open '%s' for reading"), filename);
+	}
+
+	state->author_name = read_shell_var(fp, "GIT_AUTHOR_NAME");
+	if (!state->author_name) {
+		fclose(fp);
+		return -1;
+	}
+
+	state->author_email = read_shell_var(fp, "GIT_AUTHOR_EMAIL");
+	if (!state->author_email) {
+		fclose(fp);
+		return -1;
+	}
+
+	state->author_date = read_shell_var(fp, "GIT_AUTHOR_DATE");
+	if (!state->author_date) {
+		fclose(fp);
+		return -1;
+	}
+
+	if (fgetc(fp) != EOF) {
+		fclose(fp);
+		return -1;
+	}
+
+	fclose(fp);
+	return 0;
+}
+
+/**
+ * Saves state->author_name, state->author_email and state->author_date in the
+ * state directory's "author-script" file.
+ */
+static void write_author_script(const struct am_state *state)
+{
+	struct strbuf sb = STRBUF_INIT;
+
+	strbuf_addstr(&sb, "GIT_AUTHOR_NAME=");
+	sq_quote_buf(&sb, state->author_name);
+	strbuf_addch(&sb, '\n');
+
+	strbuf_addstr(&sb, "GIT_AUTHOR_EMAIL=");
+	sq_quote_buf(&sb, state->author_email);
+	strbuf_addch(&sb, '\n');
+
+	strbuf_addstr(&sb, "GIT_AUTHOR_DATE=");
+	sq_quote_buf(&sb, state->author_date);
+	strbuf_addch(&sb, '\n');
+
+	write_file(am_path(state, "author-script"), 1, "%s", sb.buf);
+
+	strbuf_release(&sb);
+}
+
+/**
+ * Reads the commit message from the state directory's "final-commit" file,
+ * setting state->msg to its contents and state->msg_len to the length of its
+ * contents in bytes.
+ *
+ * Returns 0 on success, -1 if the file does not exist.
+ */
+static int read_commit_msg(struct am_state *state)
+{
+	struct strbuf sb = STRBUF_INIT;
+
+	assert(!state->msg);
+
+	if (read_state_file(&sb, state, "final-commit", 0) < 0) {
+		strbuf_release(&sb);
+		return -1;
+	}
+
+	state->msg = strbuf_detach(&sb, &state->msg_len);
+	return 0;
+}
+
+/**
+ * Saves state->msg in the state directory's "final-commit" file.
+ */
+static void write_commit_msg(const struct am_state *state)
+{
+	int fd;
+	const char *filename = am_path(state, "final-commit");
+
+	fd = xopen(filename, O_WRONLY | O_CREAT, 0666);
+	if (write_in_full(fd, state->msg, state->msg_len) < 0)
+		die_errno(_("could not write to %s"), filename);
+	close(fd);
+}
+
+/**
  * Loads state from disk.
  */
 static void am_load(struct am_state *state)
@@ -126,6 +309,11 @@ static void am_load(struct am_state *state)
 		die("BUG: state file 'last' does not exist");
 	state->last = strtol(sb.buf, NULL, 10);
 
+	if (read_author_script(state) < 0)
+		die(_("could not parse author script"));
+
+	read_commit_msg(state);
+
 	strbuf_release(&sb);
 }
 
@@ -318,19 +506,148 @@ static void am_setup(struct am_state *state, enum patch_format patch_format,
  */
 static void am_next(struct am_state *state)
 {
+	free(state->author_name);
+	state->author_name = NULL;
+
+	free(state->author_email);
+	state->author_email = NULL;
+
+	free(state->author_date);
+	state->author_date = NULL;
+
+	free(state->msg);
+	state->msg = NULL;
+	state->msg_len = 0;
+
+	unlink(am_path(state, "author-script"));
+	unlink(am_path(state, "final-commit"));
+
 	state->cur++;
 	write_file(am_path(state, "next"), 1, "%d", state->cur);
 }
 
 /**
+ * Returns the filename of the current patch email.
+ */
+static const char *msgnum(const struct am_state *state)
+{
+	static struct strbuf sb = STRBUF_INIT;
+
+	strbuf_reset(&sb);
+	strbuf_addf(&sb, "%0*d", state->prec, state->cur);
+
+	return sb.buf;
+}
+
+/**
+ * Parses `mail` using git-mailinfo, extracting its patch and authorship info.
+ * state->msg will be set to the patch message. state->author_name,
+ * state->author_email and state->author_date will be set to the patch author's
+ * name, email and date respectively. The patch body will be written to the
+ * state directory's "patch" file.
+ *
+ * Returns 1 if the patch should be skipped, 0 otherwise.
+ */
+static int parse_mail(struct am_state *state, const char *mail)
+{
+	FILE *fp;
+	struct child_process cp = CHILD_PROCESS_INIT;
+	struct strbuf sb = STRBUF_INIT;
+	struct strbuf msg = STRBUF_INIT;
+	struct strbuf author_name = STRBUF_INIT;
+	struct strbuf author_date = STRBUF_INIT;
+	struct strbuf author_email = STRBUF_INIT;
+	int ret = 0;
+
+	cp.git_cmd = 1;
+	cp.in = xopen(mail, O_RDONLY, 0);
+	cp.out = xopen(am_path(state, "info"), O_WRONLY | O_CREAT, 0777);
+
+	argv_array_push(&cp.args, "mailinfo");
+	argv_array_push(&cp.args, am_path(state, "msg"));
+	argv_array_push(&cp.args, am_path(state, "patch"));
+
+	if (run_command(&cp) < 0)
+		die("could not parse patch");
+
+	close(cp.in);
+	close(cp.out);
+
+	/* Extract message and author information */
+	fp = xfopen(am_path(state, "info"), "r");
+	while (!strbuf_getline(&sb, fp, '\n')) {
+		const char *x;
+
+		if (skip_prefix(sb.buf, "Subject: ", &x)) {
+			if (msg.len)
+				strbuf_addch(&msg, '\n');
+			strbuf_addstr(&msg, x);
+		} else if (skip_prefix(sb.buf, "Author: ", &x))
+			strbuf_addstr(&author_name, x);
+		else if (skip_prefix(sb.buf, "Email: ", &x))
+			strbuf_addstr(&author_email, x);
+		else if (skip_prefix(sb.buf, "Date: ", &x))
+			strbuf_addstr(&author_date, x);
+	}
+	fclose(fp);
+
+	/* Skip pine's internal folder data */
+	if (!strcmp(author_name.buf, "Mail System Internal Data")) {
+		ret = 1;
+		goto finish;
+	}
+
+	if (is_empty_file(am_path(state, "patch"))) {
+		printf_ln(_("Patch is empty. Was it split wrong?"));
+		exit(128);
+	}
+
+	strbuf_addstr(&msg, "\n\n");
+	if (strbuf_read_file(&msg, am_path(state, "msg"), 0) < 0)
+		die_errno(_("could not read '%s'"), am_path(state, "msg"));
+	stripspace(&msg, 0);
+
+	assert(!state->author_name);
+	state->author_name = strbuf_detach(&author_name, NULL);
+
+	assert(!state->author_email);
+	state->author_email = strbuf_detach(&author_email, NULL);
+
+	assert(!state->author_date);
+	state->author_date = strbuf_detach(&author_date, NULL);
+
+	assert(!state->msg);
+	state->msg = strbuf_detach(&msg, &state->msg_len);
+
+finish:
+	strbuf_release(&msg);
+	strbuf_release(&author_date);
+	strbuf_release(&author_email);
+	strbuf_release(&author_name);
+	strbuf_release(&sb);
+	return ret;
+}
+
+/**
  * Applies all queued mail.
  */
 static void am_run(struct am_state *state)
 {
 	while (state->cur <= state->last) {
+		const char *mail = am_path(state, msgnum(state));
+
+		if (!file_exists(mail))
+			goto next;
+
+		if (parse_mail(state, mail))
+			goto next; /* mail should be skipped */
+
+		write_author_script(state);
+		write_commit_msg(state);
 
 		/* NEEDSWORK: Patch application not implemented yet */
 
+next:
 		am_next(state);
 	}
 
-- 
2.5.0.rc2.110.gb39b692

[PATCH v6 08/45] builtin-am: apply patch with git-apply

[Paul Tan]

Implement applying the patch to the index using git-apply.

If a file is unchanged but stat-dirty, git-apply may erroneously fail to
apply patches, thinking that they conflict with a dirty working tree.

As such, since 2a6f08a (am: refresh the index at start and --resolved,
2011-08-15), git-am will refresh the index before applying patches.
Re-implement this behavior.

Helped-by: Junio C Hamano <gitster@pobox.com>
Signed-off-by: Paul Tan <pyokagan@gmail.com>
---

Notes:
    v6
    
    * refresh_and_write_cache(): use a heap-allocated lock_file instead of a
      static-allocated one to allow the function to be reentrant.
    
    * refresh_and_write_cache(): remove the rollback_lock_file() -- since we
      ensure that the write_locked_index() succeeds there is no need to call
      it.

 builtin/am.c | 72 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++-
 1 file changed, 71 insertions(+), 1 deletion(-)

diff --git a/builtin/am.c b/builtin/am.c
index 63f0fa4..1f198e4 100644
--- a/builtin/am.c
+++ b/builtin/am.c
@@ -10,6 +10,7 @@
 #include "dir.h"
 #include "run-command.h"
 #include "quote.h"
+#include "lockfile.h"
 
 /**
  * Returns 1 if the file is empty or does not exist, 0 otherwise.
@@ -42,6 +43,14 @@ static int strbuf_getline_crlf(struct strbuf *sb, FILE *fp)
 	return 0;
 }
 
+/**
+ * Returns the length of the first line of msg.
+ */
+static int linelen(const char *msg)
+{
+	return strchrnul(msg, '\n') - msg;
+}
+
 enum patch_format {
 	PATCH_FORMAT_UNKNOWN = 0,
 	PATCH_FORMAT_MBOX
@@ -540,6 +549,19 @@ static const char *msgnum(const struct am_state *state)
 }
 
 /**
+ * Refresh and write index.
+ */
+static void refresh_and_write_cache(void)
+{
+	struct lock_file *lock_file = xcalloc(1, sizeof(struct lock_file));
+
+	hold_locked_index(lock_file, 1);
+	refresh_cache(REFRESH_QUIET);
+	if (write_locked_index(&the_index, lock_file, COMMIT_LOCK))
+		die(_("unable to write index file"));
+}
+
+/**
  * Parses `mail` using git-mailinfo, extracting its patch and authorship info.
  * state->msg will be set to the patch message. state->author_name,
  * state->author_email and state->author_date will be set to the patch author's
@@ -629,10 +651,35 @@ finish:
 }
 
 /**
+ * Applies current patch with git-apply. Returns 0 on success, -1 otherwise.
+ */
+static int run_apply(const struct am_state *state)
+{
+	struct child_process cp = CHILD_PROCESS_INIT;
+
+	cp.git_cmd = 1;
+
+	argv_array_push(&cp.args, "apply");
+	argv_array_push(&cp.args, "--index");
+	argv_array_push(&cp.args, am_path(state, "patch"));
+
+	if (run_command(&cp))
+		return -1;
+
+	/* Reload index as git-apply will have modified it. */
+	discard_cache();
+	read_cache();
+
+	return 0;
+}
+
+/**
  * Applies all queued mail.
  */
 static void am_run(struct am_state *state)
 {
+	refresh_and_write_cache();
+
 	while (state->cur <= state->last) {
 		const char *mail = am_path(state, msgnum(state));
 
@@ -645,7 +692,27 @@ static void am_run(struct am_state *state)
 		write_author_script(state);
 		write_commit_msg(state);
 
-		/* NEEDSWORK: Patch application not implemented yet */
+		printf_ln(_("Applying: %.*s"), linelen(state->msg), state->msg);
+
+		if (run_apply(state) < 0) {
+			int advice_amworkdir = 1;
+
+			printf_ln(_("Patch failed at %s %.*s"), msgnum(state),
+				linelen(state->msg), state->msg);
+
+			git_config_get_bool("advice.amworkdir", &advice_amworkdir);
+
+			if (advice_amworkdir)
+				printf_ln(_("The copy of the patch that failed is found in: %s"),
+						am_path(state, "patch"));
+
+			exit(128);
+		}
+
+		/*
+		 * NEEDSWORK: After the patch has been applied to the index
+		 * with git-apply, we need to make commit as well.
+		 */
 
 next:
 		am_next(state);
@@ -707,6 +774,9 @@ int cmd_am(int argc, const char **argv, const char *prefix)
 
 	argc = parse_options(argc, argv, prefix, options, usage, 0);
 
+	if (read_index_preload(&the_index, NULL) < 0)
+		die(_("failed to read the index"));
+
 	if (am_in_progress(&state))
 		am_load(&state);
 	else {
-- 
2.5.0.rc2.110.gb39b692

[PATCH v6 09/45] builtin-am: implement committing applied patch

[Paul Tan]

Implement do_commit(), which commits the index which contains the
results of applying the patch, along with the extracted commit message
and authorship information.

Since 29b6754 (am: remove rebase-apply directory before gc, 2010-02-22),
git gc --auto is also invoked to pack the loose objects that are created
from making the commits.

Signed-off-by: Paul Tan <pyokagan@gmail.com>
---
 builtin/am.c | 55 +++++++++++++++++++++++++++++++++++++++++++++++++++----
 1 file changed, 51 insertions(+), 4 deletions(-)

diff --git a/builtin/am.c b/builtin/am.c
index 1f198e4..a2811b6 100644
--- a/builtin/am.c
+++ b/builtin/am.c
@@ -11,6 +11,9 @@
 #include "run-command.h"
 #include "quote.h"
 #include "lockfile.h"
+#include "cache-tree.h"
+#include "refs.h"
+#include "commit.h"
 
 /**
  * Returns 1 if the file is empty or does not exist, 0 otherwise.
@@ -674,10 +677,56 @@ static int run_apply(const struct am_state *state)
 }
 
 /**
+ * Commits the current index with state->msg as the commit message and
+ * state->author_name, state->author_email and state->author_date as the author
+ * information.
+ */
+static void do_commit(const struct am_state *state)
+{
+	unsigned char tree[GIT_SHA1_RAWSZ], parent[GIT_SHA1_RAWSZ],
+		      commit[GIT_SHA1_RAWSZ];
+	unsigned char *ptr;
+	struct commit_list *parents = NULL;
+	const char *reflog_msg, *author;
+	struct strbuf sb = STRBUF_INIT;
+
+	if (write_cache_as_tree(tree, 0, NULL))
+		die(_("git write-tree failed to write a tree"));
+
+	if (!get_sha1_commit("HEAD", parent)) {
+		ptr = parent;
+		commit_list_insert(lookup_commit(parent), &parents);
+	} else {
+		ptr = NULL;
+		fprintf_ln(stderr, _("applying to an empty history"));
+	}
+
+	author = fmt_ident(state->author_name, state->author_email,
+			state->author_date, IDENT_STRICT);
+
+	if (commit_tree(state->msg, state->msg_len, tree, parents, commit,
+				author, NULL))
+		die(_("failed to write commit object"));
+
+	reflog_msg = getenv("GIT_REFLOG_ACTION");
+	if (!reflog_msg)
+		reflog_msg = "am";
+
+	strbuf_addf(&sb, "%s: %.*s", reflog_msg, linelen(state->msg),
+			state->msg);
+
+	update_ref(sb.buf, "HEAD", commit, ptr, 0, UPDATE_REFS_DIE_ON_ERR);
+
+	strbuf_release(&sb);
+}
+
+/**
  * Applies all queued mail.
  */
 static void am_run(struct am_state *state)
 {
+	const char *argv_gc_auto[] = {"gc", "--auto", NULL};
+
 	refresh_and_write_cache();
 
 	while (state->cur <= state->last) {
@@ -709,16 +758,14 @@ static void am_run(struct am_state *state)
 			exit(128);
 		}
 
-		/*
-		 * NEEDSWORK: After the patch has been applied to the index
-		 * with git-apply, we need to make commit as well.
-		 */
+		do_commit(state);
 
 next:
 		am_next(state);
 	}
 
 	am_destroy(state);
+	run_command_v_opt(argv_gc_auto, RUN_GIT_CMD);
 }
 
 /**
-- 
2.5.0.rc2.110.gb39b692

[PATCH v6 10/45] builtin-am: refuse to apply patches if index is dirty

[Paul Tan]

Since d1c5f2a (Add git-am, applymbox replacement., 2005-10-07), git-am
will refuse to apply patches if the index is dirty. Re-implement this
behavior in builtin/am.c.

Signed-off-by: Paul Tan <pyokagan@gmail.com>
---
 builtin/am.c | 45 +++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 45 insertions(+)

diff --git a/builtin/am.c b/builtin/am.c
index a2811b6..537ad62 100644
--- a/builtin/am.c
+++ b/builtin/am.c
@@ -14,6 +14,8 @@
 #include "cache-tree.h"
 #include "refs.h"
 #include "commit.h"
+#include "diff.h"
+#include "diffcore.h"
 
 /**
  * Returns 1 if the file is empty or does not exist, 0 otherwise.
@@ -565,6 +567,43 @@ static void refresh_and_write_cache(void)
 }
 
 /**
+ * Returns 1 if the index differs from HEAD, 0 otherwise. When on an unborn
+ * branch, returns 1 if there are entries in the index, 0 otherwise. If an
+ * strbuf is provided, the space-separated list of files that differ will be
+ * appended to it.
+ */
+static int index_has_changes(struct strbuf *sb)
+{
+	unsigned char head[GIT_SHA1_RAWSZ];
+	int i;
+
+	if (!get_sha1_tree("HEAD", head)) {
+		struct diff_options opt;
+
+		diff_setup(&opt);
+		DIFF_OPT_SET(&opt, EXIT_WITH_STATUS);
+		if (!sb)
+			DIFF_OPT_SET(&opt, QUICK);
+		do_diff_cache(head, &opt);
+		diffcore_std(&opt);
+		for (i = 0; sb && i < diff_queued_diff.nr; i++) {
+			if (i)
+				strbuf_addch(sb, ' ');
+			strbuf_addstr(sb, diff_queued_diff.queue[i]->two->path);
+		}
+		diff_flush(&opt);
+		return DIFF_OPT_TST(&opt, HAS_CHANGES) != 0;
+	} else {
+		for (i = 0; sb && i < active_nr; i++) {
+			if (i)
+				strbuf_addch(sb, ' ');
+			strbuf_addstr(sb, active_cache[i]->name);
+		}
+		return !!active_nr;
+	}
+}
+
+/**
  * Parses `mail` using git-mailinfo, extracting its patch and authorship info.
  * state->msg will be set to the patch message. state->author_name,
  * state->author_email and state->author_date will be set to the patch author's
@@ -726,9 +765,15 @@ static void do_commit(const struct am_state *state)
 static void am_run(struct am_state *state)
 {
 	const char *argv_gc_auto[] = {"gc", "--auto", NULL};
+	struct strbuf sb = STRBUF_INIT;
 
 	refresh_and_write_cache();
 
+	if (index_has_changes(&sb))
+		die(_("Dirty index: cannot apply patches (dirty: %s)"), sb.buf);
+
+	strbuf_release(&sb);
+
 	while (state->cur <= state->last) {
 		const char *mail = am_path(state, msgnum(state));
 
-- 
2.5.0.rc2.110.gb39b692

[PATCH v6 11/45] builtin-am: implement --resolved/--continue

[Paul Tan]

Since 0c15cc9 (git-am: --resolved., 2005-11-16), git-am supported
resuming from a failed patch application. The user will manually apply
the patch, and the run git am --resolved which will then commit the
resulting index. Re-implement this feature by introducing am_resolve().

Since it makes no sense for the user to run am --resolved when there is
no session in progress, we error out in this case.

Signed-off-by: Paul Tan <pyokagan@gmail.com>
---

Notes:
    v6
    
    * Extracted out the validation of the state directory for resuming into
      a separate validate_resume_state() function, so that it can be shared
      with the next patch.

 builtin/am.c | 72 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++-
 1 file changed, 71 insertions(+), 1 deletion(-)

diff --git a/builtin/am.c b/builtin/am.c
index 537ad62..fd26721 100644
--- a/builtin/am.c
+++ b/builtin/am.c
@@ -760,6 +760,21 @@ static void do_commit(const struct am_state *state)
 }
 
 /**
+ * Validates the am_state for resuming -- the "msg" and authorship fields must
+ * be filled up.
+ */
+static void validate_resume_state(const struct am_state *state)
+{
+	if (!state->msg)
+		die(_("cannot resume: %s does not exist."),
+			am_path(state, "final-commit"));
+
+	if (!state->author_name || !state->author_email || !state->author_date)
+		die(_("cannot resume: %s does not exist."),
+			am_path(state, "author-script"));
+}
+
+/**
  * Applies all queued mail.
  */
 static void am_run(struct am_state *state)
@@ -814,6 +829,36 @@ next:
 }
 
 /**
+ * Resume the current am session after patch application failure. The user did
+ * all the hard work, and we do not have to do any patch application. Just
+ * trust and commit what the user has in the index and working tree.
+ */
+static void am_resolve(struct am_state *state)
+{
+	validate_resume_state(state);
+
+	printf_ln(_("Applying: %.*s"), linelen(state->msg), state->msg);
+
+	if (!index_has_changes(NULL)) {
+		printf_ln(_("No changes - did you forget to use 'git add'?\n"
+			"If there is nothing left to stage, chances are that something else\n"
+			"already introduced the same changes; you might want to skip this patch."));
+		exit(128);
+	}
+
+	if (unmerged_cache()) {
+		printf_ln(_("You still have unmerged paths in your index.\n"
+			"Did you forget to use 'git add'?"));
+		exit(128);
+	}
+
+	do_commit(state);
+
+	am_next(state);
+	am_run(state);
+}
+
+/**
  * parse_options() callback that validates and sets opt->value to the
  * PATCH_FORMAT_* enum value corresponding to `arg`.
  */
@@ -828,13 +873,20 @@ static int parse_opt_patchformat(const struct option *opt, const char *arg, int
 	return 0;
 }
 
+enum resume_mode {
+	RESUME_FALSE = 0,
+	RESUME_RESOLVED
+};
+
 int cmd_am(int argc, const char **argv, const char *prefix)
 {
 	struct am_state state;
 	int patch_format = PATCH_FORMAT_UNKNOWN;
+	enum resume_mode resume = RESUME_FALSE;
 
 	const char * const usage[] = {
 		N_("git am [options] [(<mbox>|<Maildir>)...]"),
+		N_("git am [options] --continue"),
 		NULL
 	};
 
@@ -842,6 +894,12 @@ int cmd_am(int argc, const char **argv, const char *prefix)
 		OPT_CALLBACK(0, "patch-format", &patch_format, N_("format"),
 			N_("format the patch(es) are in"),
 			parse_opt_patchformat),
+		OPT_CMDMODE(0, "continue", &resume,
+			N_("continue applying patches after resolving a conflict"),
+			RESUME_RESOLVED),
+		OPT_CMDMODE('r', "resolved", &resume,
+			N_("synonyms for --continue"),
+			RESUME_RESOLVED),
 		OPT_END()
 	};
 
@@ -875,6 +933,9 @@ int cmd_am(int argc, const char **argv, const char *prefix)
 		struct argv_array paths = ARGV_ARRAY_INIT;
 		int i;
 
+		if (resume)
+			die(_("Resolve operation not in progress, we are not resuming."));
+
 		for (i = 0; i < argc; i++) {
 			if (is_absolute_path(argv[i]) || !prefix)
 				argv_array_push(&paths, argv[i]);
@@ -887,7 +948,16 @@ int cmd_am(int argc, const char **argv, const char *prefix)
 		argv_array_clear(&paths);
 	}
 
-	am_run(&state);
+	switch (resume) {
+	case RESUME_FALSE:
+		am_run(&state);
+		break;
+	case RESUME_RESOLVED:
+		am_resolve(&state);
+		break;
+	default:
+		die("BUG: invalid resume value");
+	}
 
 	am_state_release(&state);
 
-- 
2.5.0.rc2.110.gb39b692

[PATCH v6 12/45] builtin-am: don't parse mail when resuming

[Paul Tan]

Since 271440e (git-am: make it easier after fixing up an unapplicable
patch., 2005-10-25), when "git am" is run again after being paused, the
current mail message will not be re-parsed, but instead the contents of
the state directory's patch, msg and author-script files will be used
as-is instead.

Re-implement this in builtin/am.c.

Signed-off-by: Paul Tan <pyokagan@gmail.com>
---

Notes:
    v6
    
    New patch. A test for this in t4150 would be something like this:
    
    test_expect_success 'do not parse mail when resuming' '
    	rm -fr .git/rebase-apply &&
    	git reset --hard &&
    	git checkout lorem2^^ &&
    	test_must_fail git am lorem-move.patch &&
    	test_path_is_dir .git/rebase-apply &&
    	test_cmp_rev lorem2^^ HEAD &&
    	echo resolved >file &&
    	git diff >.git/rebase-apply/patch &&
    	git reset --hard &&
    	git am <&6 &&
    	test_path_is_missing .git/rebase-apply &&
    	test resolved = "$(cat file)"
    '
    
    However, it relies on stdin being a TTY so I can't add it to the
    more-am-tests patch series :-/

 builtin/am.c | 34 +++++++++++++++++++++++++---------
 1 file changed, 25 insertions(+), 9 deletions(-)

diff --git a/builtin/am.c b/builtin/am.c
index fd26721..ec579a6 100644
--- a/builtin/am.c
+++ b/builtin/am.c
@@ -776,8 +776,12 @@ static void validate_resume_state(const struct am_state *state)
 
 /**
  * Applies all queued mail.
+ *
+ * If `resume` is true, we are "resuming". The "msg" and authorship fields, as
+ * well as the state directory's "patch" file is used as-is for applying the
+ * patch and committing it.
  */
-static void am_run(struct am_state *state)
+static void am_run(struct am_state *state, int resume)
 {
 	const char *argv_gc_auto[] = {"gc", "--auto", NULL};
 	struct strbuf sb = STRBUF_INIT;
@@ -795,11 +799,16 @@ static void am_run(struct am_state *state)
 		if (!file_exists(mail))
 			goto next;
 
-		if (parse_mail(state, mail))
-			goto next; /* mail should be skipped */
+		if (resume) {
+			validate_resume_state(state);
+			resume = 0;
+		} else {
+			if (parse_mail(state, mail))
+				goto next; /* mail should be skipped */
 
-		write_author_script(state);
-		write_commit_msg(state);
+			write_author_script(state);
+			write_commit_msg(state);
+		}
 
 		printf_ln(_("Applying: %.*s"), linelen(state->msg), state->msg);
 
@@ -855,7 +864,7 @@ static void am_resolve(struct am_state *state)
 	do_commit(state);
 
 	am_next(state);
-	am_run(state);
+	am_run(state, 0);
 }
 
 /**
@@ -875,6 +884,7 @@ static int parse_opt_patchformat(const struct option *opt, const char *arg, int
 
 enum resume_mode {
 	RESUME_FALSE = 0,
+	RESUME_APPLY,
 	RESUME_RESOLVED
 };
 
@@ -927,9 +937,12 @@ int cmd_am(int argc, const char **argv, const char *prefix)
 	if (read_index_preload(&the_index, NULL) < 0)
 		die(_("failed to read the index"));
 
-	if (am_in_progress(&state))
+	if (am_in_progress(&state)) {
+		if (resume == RESUME_FALSE)
+			resume = RESUME_APPLY;
+
 		am_load(&state);
-	else {
+	} else {
 		struct argv_array paths = ARGV_ARRAY_INIT;
 		int i;
 
@@ -950,7 +963,10 @@ int cmd_am(int argc, const char **argv, const char *prefix)
 
 	switch (resume) {
 	case RESUME_FALSE:
-		am_run(&state);
+		am_run(&state, 0);
+		break;
+	case RESUME_APPLY:
+		am_run(&state, 1);
 		break;
 	case RESUME_RESOLVED:
 		am_resolve(&state);
-- 
2.5.0.rc2.110.gb39b692

[PATCH v6 13/45] builtin-am: implement --skip

[Paul Tan]

Since d1c5f2a (Add git-am, applymbox replacement., 2005-10-07), git-am
supported resuming from a failed patch application by skipping the
current patch. Re-implement this feature by introducing am_skip().

Helped-by: Stefan Beller <sbeller@google.com>
Signed-off-by: Paul Tan <pyokagan@gmail.com>
---

Notes:
    v6
    
    * Moved lock_file memory allocation to just before the
      hold_locked_index() to prevent memory leaks.

 builtin/am.c | 123 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++-
 1 file changed, 121 insertions(+), 2 deletions(-)

diff --git a/builtin/am.c b/builtin/am.c
index ec579a6..765844b 100644
--- a/builtin/am.c
+++ b/builtin/am.c
@@ -16,6 +16,8 @@
 #include "commit.h"
 #include "diff.h"
 #include "diffcore.h"
+#include "unpack-trees.h"
+#include "branch.h"
 
 /**
  * Returns 1 if the file is empty or does not exist, 0 otherwise.
@@ -868,6 +870,116 @@ static void am_resolve(struct am_state *state)
 }
 
 /**
+ * Performs a checkout fast-forward from `head` to `remote`. If `reset` is
+ * true, any unmerged entries will be discarded. Returns 0 on success, -1 on
+ * failure.
+ */
+static int fast_forward_to(struct tree *head, struct tree *remote, int reset)
+{
+	struct lock_file *lock_file;
+	struct unpack_trees_options opts;
+	struct tree_desc t[2];
+
+	if (parse_tree(head) || parse_tree(remote))
+		return -1;
+
+	lock_file = xcalloc(1, sizeof(struct lock_file));
+	hold_locked_index(lock_file, 1);
+
+	refresh_cache(REFRESH_QUIET);
+
+	memset(&opts, 0, sizeof(opts));
+	opts.head_idx = 1;
+	opts.src_index = &the_index;
+	opts.dst_index = &the_index;
+	opts.update = 1;
+	opts.merge = 1;
+	opts.reset = reset;
+	opts.fn = twoway_merge;
+	init_tree_desc(&t[0], head->buffer, head->size);
+	init_tree_desc(&t[1], remote->buffer, remote->size);
+
+	if (unpack_trees(2, t, &opts)) {
+		rollback_lock_file(lock_file);
+		return -1;
+	}
+
+	if (write_locked_index(&the_index, lock_file, COMMIT_LOCK))
+		die(_("unable to write new index file"));
+
+	return 0;
+}
+
+/**
+ * Clean the index without touching entries that are not modified between
+ * `head` and `remote`.
+ */
+static int clean_index(const unsigned char *head, const unsigned char *remote)
+{
+	struct lock_file *lock_file;
+	struct tree *head_tree, *remote_tree, *index_tree;
+	unsigned char index[GIT_SHA1_RAWSZ];
+	struct pathspec pathspec;
+
+	head_tree = parse_tree_indirect(head);
+	if (!head_tree)
+		return error(_("Could not parse object '%s'."), sha1_to_hex(head));
+
+	remote_tree = parse_tree_indirect(remote);
+	if (!remote_tree)
+		return error(_("Could not parse object '%s'."), sha1_to_hex(remote));
+
+	read_cache_unmerged();
+
+	if (fast_forward_to(head_tree, head_tree, 1))
+		return -1;
+
+	if (write_cache_as_tree(index, 0, NULL))
+		return -1;
+
+	index_tree = parse_tree_indirect(index);
+	if (!index_tree)
+		return error(_("Could not parse object '%s'."), sha1_to_hex(index));
+
+	if (fast_forward_to(index_tree, remote_tree, 0))
+		return -1;
+
+	memset(&pathspec, 0, sizeof(pathspec));
+
+	lock_file = xcalloc(1, sizeof(struct lock_file));
+	hold_locked_index(lock_file, 1);
+
+	if (read_tree(remote_tree, 0, &pathspec)) {
+		rollback_lock_file(lock_file);
+		return -1;
+	}
+
+	if (write_locked_index(&the_index, lock_file, COMMIT_LOCK))
+		die(_("unable to write new index file"));
+
+	remove_branch_state();
+
+	return 0;
+}
+
+/**
+ * Resume the current am session by skipping the current patch.
+ */
+static void am_skip(struct am_state *state)
+{
+	unsigned char head[GIT_SHA1_RAWSZ];
+
+	if (get_sha1("HEAD", head))
+		hashcpy(head, EMPTY_TREE_SHA1_BIN);
+
+	if (clean_index(head, head))
+		die(_("failed to clean index"));
+
+	am_next(state);
+	am_run(state, 0);
+}
+
+/**
  * parse_options() callback that validates and sets opt->value to the
  * PATCH_FORMAT_* enum value corresponding to `arg`.
  */
@@ -885,7 +997,8 @@ static int parse_opt_patchformat(const struct option *opt, const char *arg, int
 enum resume_mode {
 	RESUME_FALSE = 0,
 	RESUME_APPLY,
-	RESUME_RESOLVED
+	RESUME_RESOLVED,
+	RESUME_SKIP
 };
 
 int cmd_am(int argc, const char **argv, const char *prefix)
@@ -896,7 +1009,7 @@ int cmd_am(int argc, const char **argv, const char *prefix)
 
 	const char * const usage[] = {
 		N_("git am [options] [(<mbox>|<Maildir>)...]"),
-		N_("git am [options] --continue"),
+		N_("git am [options] (--continue | --skip)"),
 		NULL
 	};
 
@@ -910,6 +1023,9 @@ int cmd_am(int argc, const char **argv, const char *prefix)
 		OPT_CMDMODE('r', "resolved", &resume,
 			N_("synonyms for --continue"),
 			RESUME_RESOLVED),
+		OPT_CMDMODE(0, "skip", &resume,
+			N_("skip the current patch"),
+			RESUME_SKIP),
 		OPT_END()
 	};
 
@@ -971,6 +1087,9 @@ int cmd_am(int argc, const char **argv, const char *prefix)
 	case RESUME_RESOLVED:
 		am_resolve(&state);
 		break;
+	case RESUME_SKIP:
+		am_skip(&state);
+		break;
 	default:
 		die("BUG: invalid resume value");
 	}
-- 
2.5.0.rc2.110.gb39b692

[PATCH v6 14/45] builtin-am: implement --abort

[Paul Tan]

Since 3e5057a (git am --abort, 2008-07-16), git-am supported the --abort
option that will rewind HEAD back to the original commit. Re-implement
this through am_abort().

Since 7b3b7e3 (am --abort: keep unrelated commits since the last failure
and warn, 2010-12-21), to prevent commits made since the last failure
from being lost, git-am will not rewind HEAD back to the original
commit if HEAD moved since the last failure. Re-implement this through
safe_to_abort().

Signed-off-by: Paul Tan <pyokagan@gmail.com>
---
 builtin/am.c | 102 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++--
 1 file changed, 99 insertions(+), 3 deletions(-)

diff --git a/builtin/am.c b/builtin/am.c
index 765844b..8a054ee 100644
--- a/builtin/am.c
+++ b/builtin/am.c
@@ -490,6 +490,8 @@ static int split_mail(struct am_state *state, enum patch_format patch_format,
 static void am_setup(struct am_state *state, enum patch_format patch_format,
 			const char **paths)
 {
+	unsigned char curr_head[GIT_SHA1_RAWSZ];
+
 	if (!patch_format)
 		patch_format = detect_patch_format(paths);
 
@@ -506,6 +508,14 @@ static void am_setup(struct am_state *state, enum patch_format patch_format,
 		die(_("Failed to split patches."));
 	}
 
+	if (!get_sha1("HEAD", curr_head)) {
+		write_file(am_path(state, "abort-safety"), 1, "%s", sha1_to_hex(curr_head));
+		update_ref("am", "ORIG_HEAD", curr_head, NULL, 0, UPDATE_REFS_DIE_ON_ERR);
+	} else {
+		write_file(am_path(state, "abort-safety"), 1, "%s", "");
+		delete_ref("ORIG_HEAD", NULL, 0);
+	}
+
 	/*
 	 * NOTE: Since the "next" and "last" files determine if an am_state
 	 * session is in progress, they should be written last.
@@ -522,6 +532,8 @@ static void am_setup(struct am_state *state, enum patch_format patch_format,
  */
 static void am_next(struct am_state *state)
 {
+	unsigned char head[GIT_SHA1_RAWSZ];
+
 	free(state->author_name);
 	state->author_name = NULL;
 
@@ -538,6 +550,11 @@ static void am_next(struct am_state *state)
 	unlink(am_path(state, "author-script"));
 	unlink(am_path(state, "final-commit"));
 
+	if (!get_sha1("HEAD", head))
+		write_file(am_path(state, "abort-safety"), 1, "%s", sha1_to_hex(head));
+	else
+		write_file(am_path(state, "abort-safety"), 1, "%s", "");
+
 	state->cur++;
 	write_file(am_path(state, "next"), 1, "%d", state->cur);
 }
@@ -788,10 +805,14 @@ static void am_run(struct am_state *state, int resume)
 	const char *argv_gc_auto[] = {"gc", "--auto", NULL};
 	struct strbuf sb = STRBUF_INIT;
 
+	unlink(am_path(state, "dirtyindex"));
+
 	refresh_and_write_cache();
 
-	if (index_has_changes(&sb))
+	if (index_has_changes(&sb)) {
+		write_file(am_path(state, "dirtyindex"), 1, "t");
 		die(_("Dirty index: cannot apply patches (dirty: %s)"), sb.buf);
+	}
 
 	strbuf_release(&sb);
 
@@ -980,6 +1001,74 @@ static void am_skip(struct am_state *state)
 }
 
 /**
+ * Returns true if it is safe to reset HEAD to the ORIG_HEAD, false otherwise.
+ *
+ * It is not safe to reset HEAD when:
+ * 1. git-am previously failed because the index was dirty.
+ * 2. HEAD has moved since git-am previously failed.
+ */
+static int safe_to_abort(const struct am_state *state)
+{
+	struct strbuf sb = STRBUF_INIT;
+	unsigned char abort_safety[GIT_SHA1_RAWSZ], head[GIT_SHA1_RAWSZ];
+
+	if (file_exists(am_path(state, "dirtyindex")))
+		return 0;
+
+	if (read_state_file(&sb, state, "abort-safety", 1) > 0) {
+		if (get_sha1_hex(sb.buf, abort_safety))
+			die(_("could not parse %s"), am_path(state, "abort_safety"));
+	} else
+		hashclr(abort_safety);
+
+	if (get_sha1("HEAD", head))
+		hashclr(head);
+
+	if (!hashcmp(head, abort_safety))
+		return 1;
+
+	error(_("You seem to have moved HEAD since the last 'am' failure.\n"
+		"Not rewinding to ORIG_HEAD"));
+
+	return 0;
+}
+
+/**
+ * Aborts the current am session if it is safe to do so.
+ */
+static void am_abort(struct am_state *state)
+{
+	unsigned char curr_head[GIT_SHA1_RAWSZ], orig_head[GIT_SHA1_RAWSZ];
+	int has_curr_head, has_orig_head;
+	const char *curr_branch;
+
+	if (!safe_to_abort(state)) {
+		am_destroy(state);
+		return;
+	}
+
+	curr_branch = resolve_refdup("HEAD", 0, curr_head, NULL);
+	has_curr_head = !is_null_sha1(curr_head);
+	if (!has_curr_head)
+		hashcpy(curr_head, EMPTY_TREE_SHA1_BIN);
+
+	has_orig_head = !get_sha1("ORIG_HEAD", orig_head);
+	if (!has_orig_head)
+		hashcpy(orig_head, EMPTY_TREE_SHA1_BIN);
+
+	clean_index(curr_head, orig_head);
+
+	if (has_orig_head)
+		update_ref("am --abort", "HEAD", orig_head,
+				has_curr_head ? curr_head : NULL, 0,
+				UPDATE_REFS_DIE_ON_ERR);
+	else if (curr_branch)
+		delete_ref(curr_branch, NULL, REF_NODEREF);
+
+	am_destroy(state);
+}
+
+/**
  * parse_options() callback that validates and sets opt->value to the
  * PATCH_FORMAT_* enum value corresponding to `arg`.
  */
@@ -998,7 +1087,8 @@ enum resume_mode {
 	RESUME_FALSE = 0,
 	RESUME_APPLY,
 	RESUME_RESOLVED,
-	RESUME_SKIP
+	RESUME_SKIP,
+	RESUME_ABORT
 };
 
 int cmd_am(int argc, const char **argv, const char *prefix)
@@ -1009,7 +1099,7 @@ int cmd_am(int argc, const char **argv, const char *prefix)
 
 	const char * const usage[] = {
 		N_("git am [options] [(<mbox>|<Maildir>)...]"),
-		N_("git am [options] (--continue | --skip)"),
+		N_("git am [options] (--continue | --skip | --abort)"),
 		NULL
 	};
 
@@ -1026,6 +1116,9 @@ int cmd_am(int argc, const char **argv, const char *prefix)
 		OPT_CMDMODE(0, "skip", &resume,
 			N_("skip the current patch"),
 			RESUME_SKIP),
+		OPT_CMDMODE(0, "abort", &resume,
+			N_("restore the original branch and abort the patching operation."),
+			RESUME_ABORT),
 		OPT_END()
 	};
 
@@ -1090,6 +1183,9 @@ int cmd_am(int argc, const char **argv, const char *prefix)
 	case RESUME_SKIP:
 		am_skip(&state);
 		break;
+	case RESUME_ABORT:
+		am_abort(&state);
+		break;
 	default:
 		die("BUG: invalid resume value");
 	}
-- 
2.5.0.rc2.110.gb39b692

[PATCH v6 15/45] builtin-am: reject patches when there's a session in progress

[Paul Tan]

Since d1c5f2a (Add git-am, applymbox replacement., 2005-10-07), git-am
would error out if the user gave it mbox(s) on the command-line, but
there was a session in progress.

Since c95b138 (Fix git-am safety checks, 2006-09-15), git-am would
detect if the user attempted to feed it a mbox via stdin, by checking if
stdin is not a tty and there is no resume command given.

Re-implement the above two safety checks.

Signed-off-by: Paul Tan <pyokagan@gmail.com>
---
 builtin/am.c | 15 +++++++++++++++
 1 file changed, 15 insertions(+)

diff --git a/builtin/am.c b/builtin/am.c
index 8a054ee..fa522f5 100644
--- a/builtin/am.c
+++ b/builtin/am.c
@@ -1147,6 +1147,21 @@ int cmd_am(int argc, const char **argv, const char *prefix)
 		die(_("failed to read the index"));
 
 	if (am_in_progress(&state)) {
+		/*
+		 * Catch user error to feed us patches when there is a session
+		 * in progress:
+		 *
+		 * 1. mbox path(s) are provided on the command-line.
+		 * 2. stdin is not a tty: the user is trying to feed us a patch
+		 *    from standard input. This is somewhat unreliable -- stdin
+		 *    could be /dev/null for example and the caller did not
+		 *    intend to feed us a patch but wanted to continue
+		 *    unattended.
+		 */
+		if (argc || (resume == RESUME_FALSE && !isatty(0)))
+			die(_("previous rebase directory %s still exists but mbox given."),
+				state.dir);
+
 		if (resume == RESUME_FALSE)
 			resume = RESUME_APPLY;
 
-- 
2.5.0.rc2.110.gb39b692

[PATCH v6 16/45] builtin-am: implement -q/--quiet

[Paul Tan]

Since 0e987a1 (am, rebase: teach quiet option, 2009-06-16), git-am
supported the --quiet option, and when told to be quiet, would only
speak on failure. Re-implement this by introducing the say() function,
which works like fprintf_ln(), but would only write to the stream when
state->quiet is false.

Signed-off-by: Paul Tan <pyokagan@gmail.com>
---
 builtin/am.c | 31 ++++++++++++++++++++++++++++---
 1 file changed, 28 insertions(+), 3 deletions(-)

diff --git a/builtin/am.c b/builtin/am.c
index fa522f5..e0b86d1 100644
--- a/builtin/am.c
+++ b/builtin/am.c
@@ -80,6 +80,9 @@ struct am_state {
 
 	/* number of digits in patch filename */
 	int prec;
+
+	/* various operating modes and command line options */
+	int quiet;
 };
 
 /**
@@ -117,6 +120,22 @@ static inline const char *am_path(const struct am_state *state, const char *path
 }
 
 /**
+ * If state->quiet is false, calls fprintf(fp, fmt, ...), and appends a newline
+ * at the end.
+ */
+static void say(const struct am_state *state, FILE *fp, const char *fmt, ...)
+{
+	va_list ap;
+
+	va_start(ap, fmt);
+	if (!state->quiet) {
+		vfprintf(fp, fmt, ap);
+		putc('\n', fp);
+	}
+	va_end(ap);
+}
+
+/**
  * Returns 1 if there is an am session in progress, 0 otherwise.
  */
 static int am_in_progress(const struct am_state *state)
@@ -330,6 +349,9 @@ static void am_load(struct am_state *state)
 
 	read_commit_msg(state);
 
+	read_state_file(&sb, state, "quiet", 1);
+	state->quiet = !strcmp(sb.buf, "t");
+
 	strbuf_release(&sb);
 }
 
@@ -508,6 +530,8 @@ static void am_setup(struct am_state *state, enum patch_format patch_format,
 		die(_("Failed to split patches."));
 	}
 
+	write_file(am_path(state, "quiet"), 1, state->quiet ? "t" : "f");
+
 	if (!get_sha1("HEAD", curr_head)) {
 		write_file(am_path(state, "abort-safety"), 1, "%s", sha1_to_hex(curr_head));
 		update_ref("am", "ORIG_HEAD", curr_head, NULL, 0, UPDATE_REFS_DIE_ON_ERR);
@@ -756,7 +780,7 @@ static void do_commit(const struct am_state *state)
 		commit_list_insert(lookup_commit(parent), &parents);
 	} else {
 		ptr = NULL;
-		fprintf_ln(stderr, _("applying to an empty history"));
+		say(state, stderr, _("applying to an empty history"));
 	}
 
 	author = fmt_ident(state->author_name, state->author_email,
@@ -833,7 +857,7 @@ static void am_run(struct am_state *state, int resume)
 			write_commit_msg(state);
 		}
 
-		printf_ln(_("Applying: %.*s"), linelen(state->msg), state->msg);
+		say(state, stdout, _("Applying: %.*s"), linelen(state->msg), state->msg);
 
 		if (run_apply(state) < 0) {
 			int advice_amworkdir = 1;
@@ -869,7 +893,7 @@ static void am_resolve(struct am_state *state)
 {
 	validate_resume_state(state);
 
-	printf_ln(_("Applying: %.*s"), linelen(state->msg), state->msg);
+	say(state, stdout, _("Applying: %.*s"), linelen(state->msg), state->msg);
 
 	if (!index_has_changes(NULL)) {
 		printf_ln(_("No changes - did you forget to use 'git add'?\n"
@@ -1104,6 +1128,7 @@ int cmd_am(int argc, const char **argv, const char *prefix)
 	};
 
 	struct option options[] = {
+		OPT__QUIET(&state.quiet, N_("be quiet")),
 		OPT_CALLBACK(0, "patch-format", &patch_format, N_("format"),
 			N_("format the patch(es) are in"),
 			parse_opt_patchformat),
-- 
2.5.0.rc2.110.gb39b692

[PATCH v6 17/45] builtin-am: exit with user friendly message on failure

[Paul Tan]

Since ced9456 (Give the user a hint for how to continue in the case that
git-am fails because it requires user intervention, 2006-05-02), git-am
prints additional information on how the user can re-invoke git-am to
resume patch application after resolving the failure. Re-implement this
through the die_user_resolve() function.

Since cc12005 (Make git rebase interactive help match documentation.,
2006-05-13), git-am supports the --resolvemsg option which is used by
git-rebase to override the message printed out when git-am fails.
Re-implement this option.

Signed-off-by: Paul Tan <pyokagan@gmail.com>
---
 builtin/am.c | 30 ++++++++++++++++++++++++++----
 1 file changed, 26 insertions(+), 4 deletions(-)

diff --git a/builtin/am.c b/builtin/am.c
index e0b86d1..fb428f9 100644
--- a/builtin/am.c
+++ b/builtin/am.c
@@ -83,6 +83,7 @@ struct am_state {
 
 	/* various operating modes and command line options */
 	int quiet;
+	const char *resolvemsg;
 };
 
 /**
@@ -647,6 +648,25 @@ static int index_has_changes(struct strbuf *sb)
 }
 
 /**
+ * Dies with a user-friendly message on how to proceed after resolving the
+ * problem. This message can be overridden with state->resolvemsg.
+ */
+static void NORETURN die_user_resolve(const struct am_state *state)
+{
+	if (state->resolvemsg) {
+		printf_ln("%s", state->resolvemsg);
+	} else {
+		const char *cmdline = "git am";
+
+		printf_ln(_("When you have resolved this problem, run \"%s --continue\"."), cmdline);
+		printf_ln(_("If you prefer to skip this patch, run \"%s --skip\" instead."), cmdline);
+		printf_ln(_("To restore the original branch and stop patching, run \"%s --abort\"."), cmdline);
+	}
+
+	exit(128);
+}
+
+/**
  * Parses `mail` using git-mailinfo, extracting its patch and authorship info.
  * state->msg will be set to the patch message. state->author_name,
  * state->author_email and state->author_date will be set to the patch author's
@@ -706,7 +726,7 @@ static int parse_mail(struct am_state *state, const char *mail)
 
 	if (is_empty_file(am_path(state, "patch"))) {
 		printf_ln(_("Patch is empty. Was it split wrong?"));
-		exit(128);
+		die_user_resolve(state);
 	}
 
 	strbuf_addstr(&msg, "\n\n");
@@ -871,7 +891,7 @@ static void am_run(struct am_state *state, int resume)
 				printf_ln(_("The copy of the patch that failed is found in: %s"),
 						am_path(state, "patch"));
 
-			exit(128);
+			die_user_resolve(state);
 		}
 
 		do_commit(state);
@@ -899,13 +919,13 @@ static void am_resolve(struct am_state *state)
 		printf_ln(_("No changes - did you forget to use 'git add'?\n"
 			"If there is nothing left to stage, chances are that something else\n"
 			"already introduced the same changes; you might want to skip this patch."));
-		exit(128);
+		die_user_resolve(state);
 	}
 
 	if (unmerged_cache()) {
 		printf_ln(_("You still have unmerged paths in your index.\n"
 			"Did you forget to use 'git add'?"));
-		exit(128);
+		die_user_resolve(state);
 	}
 
 	do_commit(state);
@@ -1132,6 +1152,8 @@ int cmd_am(int argc, const char **argv, const char *prefix)
 		OPT_CALLBACK(0, "patch-format", &patch_format, N_("format"),
 			N_("format the patch(es) are in"),
 			parse_opt_patchformat),
+		OPT_STRING(0, "resolvemsg", &state.resolvemsg, NULL,
+			N_("override error message when patch failure occurs")),
 		OPT_CMDMODE(0, "continue", &resume,
 			N_("continue applying patches after resolving a conflict"),
 			RESUME_RESOLVED),
-- 
2.5.0.rc2.110.gb39b692

[PATCH v6 18/45] builtin-am: implement -s/--signoff

[Paul Tan]

Since d1c5f2a (Add git-am, applymbox replacement., 2005-10-07), git-am
supported the --signoff option which will append a signoff at the end of
the commit messsage. Re-implement this feature in parse_mail() by
calling append_signoff() if the option is set.

Signed-off-by: Paul Tan <pyokagan@gmail.com>
---
 builtin/am.c | 12 ++++++++++++
 1 file changed, 12 insertions(+)

diff --git a/builtin/am.c b/builtin/am.c
index fb428f9..7c0f604 100644
--- a/builtin/am.c
+++ b/builtin/am.c
@@ -18,6 +18,7 @@
 #include "diffcore.h"
 #include "unpack-trees.h"
 #include "branch.h"
+#include "sequencer.h"
 
 /**
  * Returns 1 if the file is empty or does not exist, 0 otherwise.
@@ -83,6 +84,7 @@ struct am_state {
 
 	/* various operating modes and command line options */
 	int quiet;
+	int append_signoff;
 	const char *resolvemsg;
 };
 
@@ -353,6 +355,9 @@ static void am_load(struct am_state *state)
 	read_state_file(&sb, state, "quiet", 1);
 	state->quiet = !strcmp(sb.buf, "t");
 
+	read_state_file(&sb, state, "sign", 1);
+	state->append_signoff = !strcmp(sb.buf, "t");
+
 	strbuf_release(&sb);
 }
 
@@ -533,6 +538,8 @@ static void am_setup(struct am_state *state, enum patch_format patch_format,
 
 	write_file(am_path(state, "quiet"), 1, state->quiet ? "t" : "f");
 
+	write_file(am_path(state, "sign"), 1, state->append_signoff ? "t" : "f");
+
 	if (!get_sha1("HEAD", curr_head)) {
 		write_file(am_path(state, "abort-safety"), 1, "%s", sha1_to_hex(curr_head));
 		update_ref("am", "ORIG_HEAD", curr_head, NULL, 0, UPDATE_REFS_DIE_ON_ERR);
@@ -734,6 +741,9 @@ static int parse_mail(struct am_state *state, const char *mail)
 		die_errno(_("could not read '%s'"), am_path(state, "msg"));
 	stripspace(&msg, 0);
 
+	if (state->append_signoff)
+		append_signoff(&msg, 0, 0);
+
 	assert(!state->author_name);
 	state->author_name = strbuf_detach(&author_name, NULL);
 
@@ -1149,6 +1159,8 @@ int cmd_am(int argc, const char **argv, const char *prefix)
 
 	struct option options[] = {
 		OPT__QUIET(&state.quiet, N_("be quiet")),
+		OPT_BOOL('s', "signoff", &state.append_signoff,
+			N_("add a Signed-off-by line to the commit message")),
 		OPT_CALLBACK(0, "patch-format", &patch_format, N_("format"),
 			N_("format the patch(es) are in"),
 			parse_opt_patchformat),
-- 
2.5.0.rc2.110.gb39b692

[PATCH v6 19/45] cache-tree: introduce write_index_as_tree()

[Paul Tan]

A caller may wish to write a temporary index as a tree. However,
write_cache_as_tree() assumes that the index was read from, and will
write to, the default index file path. Introduce write_index_as_tree()
which removes this limitation by allowing the caller to specify its own
index_state and index file path.

Signed-off-by: Paul Tan <pyokagan@gmail.com>
---
 cache-tree.c | 29 +++++++++++++++++------------
 cache-tree.h |  1 +
 2 files changed, 18 insertions(+), 12 deletions(-)

diff --git a/cache-tree.c b/cache-tree.c
index 32772b9..feace8b 100644
--- a/cache-tree.c
+++ b/cache-tree.c
@@ -592,7 +592,7 @@ static struct cache_tree *cache_tree_find(struct cache_tree *it, const char *pat
 	return it;
 }
 
-int write_cache_as_tree(unsigned char *sha1, int flags, const char *prefix)
+int write_index_as_tree(unsigned char *sha1, struct index_state *index_state, const char *index_path, int flags, const char *prefix)
 {
 	int entries, was_valid, newfd;
 	struct lock_file *lock_file;
@@ -603,23 +603,23 @@ int write_cache_as_tree(unsigned char *sha1, int flags, const char *prefix)
 	 */
 	lock_file = xcalloc(1, sizeof(struct lock_file));
 
-	newfd = hold_locked_index(lock_file, 1);
+	newfd = hold_lock_file_for_update(lock_file, index_path, LOCK_DIE_ON_ERROR);
 
-	entries = read_cache();
+	entries = read_index_from(index_state, index_path);
 	if (entries < 0)
 		return WRITE_TREE_UNREADABLE_INDEX;
 	if (flags & WRITE_TREE_IGNORE_CACHE_TREE)
-		cache_tree_free(&(active_cache_tree));
+		cache_tree_free(&index_state->cache_tree);
 
-	if (!active_cache_tree)
-		active_cache_tree = cache_tree();
+	if (!index_state->cache_tree)
+		index_state->cache_tree = cache_tree();
 
-	was_valid = cache_tree_fully_valid(active_cache_tree);
+	was_valid = cache_tree_fully_valid(index_state->cache_tree);
 	if (!was_valid) {
-		if (cache_tree_update(&the_index, flags) < 0)
+		if (cache_tree_update(index_state, flags) < 0)
 			return WRITE_TREE_UNMERGED_INDEX;
 		if (0 <= newfd) {
-			if (!write_locked_index(&the_index, lock_file, COMMIT_LOCK))
+			if (!write_locked_index(index_state, lock_file, COMMIT_LOCK))
 				newfd = -1;
 		}
 		/* Not being able to write is fine -- we are only interested
@@ -631,14 +631,14 @@ int write_cache_as_tree(unsigned char *sha1, int flags, const char *prefix)
 	}
 
 	if (prefix) {
-		struct cache_tree *subtree =
-			cache_tree_find(active_cache_tree, prefix);
+		struct cache_tree *subtree;
+		subtree = cache_tree_find(index_state->cache_tree, prefix);
 		if (!subtree)
 			return WRITE_TREE_PREFIX_ERROR;
 		hashcpy(sha1, subtree->sha1);
 	}
 	else
-		hashcpy(sha1, active_cache_tree->sha1);
+		hashcpy(sha1, index_state->cache_tree->sha1);
 
 	if (0 <= newfd)
 		rollback_lock_file(lock_file);
@@ -646,6 +646,11 @@ int write_cache_as_tree(unsigned char *sha1, int flags, const char *prefix)
 	return 0;
 }
 
+int write_cache_as_tree(unsigned char *sha1, int flags, const char *prefix)
+{
+	return write_index_as_tree(sha1, &the_index, get_index_file(), flags, prefix);
+}
+
 static void prime_cache_tree_rec(struct cache_tree *it, struct tree *tree)
 {
 	struct tree_desc desc;
diff --git a/cache-tree.h b/cache-tree.h
index aa7b3e4..41c5746 100644
--- a/cache-tree.h
+++ b/cache-tree.h
@@ -46,6 +46,7 @@ int update_main_cache_tree(int);
 #define WRITE_TREE_UNMERGED_INDEX (-2)
 #define WRITE_TREE_PREFIX_ERROR (-3)
 
+int write_index_as_tree(unsigned char *sha1, struct index_state *index_state, const char *index_path, int flags, const char *prefix);
 int write_cache_as_tree(unsigned char *sha1, int flags, const char *prefix);
 void prime_cache_tree(struct index_state *, struct tree *);
 
-- 
2.5.0.rc2.110.gb39b692

[PATCH v6 20/45] builtin-am: implement --3way, am.threeWay

[Paul Tan]

Since d1c5f2a (Add git-am, applymbox replacement., 2005-10-07),
git-am.sh supported the --3way option, and if set, would attempt to do a
3-way merge if the initial patch application fails.

Since d96a275 (git-am: add am.threeWay config variable, 2015-06-04), the
setting am.threeWay configures if the --3way option is set by default.

Since 5d86861 (am -3: list the paths that needed 3-way fallback,
2012-03-28), in a 3-way merge git-am.sh would list the paths that needed
3-way fallback, so that the user can review them more carefully to spot
mismerges.

Re-implement the above in builtin/am.c.

Signed-off-by: Paul Tan <pyokagan@gmail.com>
---
 builtin/am.c | 156 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++--
 1 file changed, 152 insertions(+), 4 deletions(-)

diff --git a/builtin/am.c b/builtin/am.c
index 7c0f604..7237fff 100644
--- a/builtin/am.c
+++ b/builtin/am.c
@@ -19,6 +19,8 @@
 #include "unpack-trees.h"
 #include "branch.h"
 #include "sequencer.h"
+#include "revision.h"
+#include "merge-recursive.h"
 
 /**
  * Returns 1 if the file is empty or does not exist, 0 otherwise.
@@ -83,6 +85,7 @@ struct am_state {
 	int prec;
 
 	/* various operating modes and command line options */
+	int threeway;
 	int quiet;
 	int append_signoff;
 	const char *resolvemsg;
@@ -100,6 +103,8 @@ static void am_state_init(struct am_state *state, const char *dir)
 	state->dir = xstrdup(dir);
 
 	state->prec = 4;
+
+	git_config_get_bool("am.threeway", &state->threeway);
 }
 
 /**
@@ -352,6 +357,9 @@ static void am_load(struct am_state *state)
 
 	read_commit_msg(state);
 
+	read_state_file(&sb, state, "threeway", 1);
+	state->threeway = !strcmp(sb.buf, "t");
+
 	read_state_file(&sb, state, "quiet", 1);
 	state->quiet = !strcmp(sb.buf, "t");
 
@@ -536,6 +544,8 @@ static void am_setup(struct am_state *state, enum patch_format patch_format,
 		die(_("Failed to split patches."));
 	}
 
+	write_file(am_path(state, "threeway"), 1, state->threeway ? "t" : "f");
+
 	write_file(am_path(state, "quiet"), 1, state->quiet ? "t" : "f");
 
 	write_file(am_path(state, "sign"), 1, state->append_signoff ? "t" : "f");
@@ -766,16 +776,34 @@ finish:
 }
 
 /**
- * Applies current patch with git-apply. Returns 0 on success, -1 otherwise.
+ * Applies current patch with git-apply. Returns 0 on success, -1 otherwise. If
+ * `index_file` is not NULL, the patch will be applied to that index.
  */
-static int run_apply(const struct am_state *state)
+static int run_apply(const struct am_state *state, const char *index_file)
 {
 	struct child_process cp = CHILD_PROCESS_INIT;
 
 	cp.git_cmd = 1;
 
+	if (index_file)
+		argv_array_pushf(&cp.env_array, "GIT_INDEX_FILE=%s", index_file);
+
+	/*
+	 * If we are allowed to fall back on 3-way merge, don't give false
+	 * errors during the initial attempt.
+	 */
+	if (state->threeway && !index_file) {
+		cp.no_stdout = 1;
+		cp.no_stderr = 1;
+	}
+
 	argv_array_push(&cp.args, "apply");
-	argv_array_push(&cp.args, "--index");
+
+	if (index_file)
+		argv_array_push(&cp.args, "--cached");
+	else
+		argv_array_push(&cp.args, "--index");
+
 	argv_array_push(&cp.args, am_path(state, "patch"));
 
 	if (run_command(&cp))
@@ -783,8 +811,106 @@ static int run_apply(const struct am_state *state)
 
 	/* Reload index as git-apply will have modified it. */
 	discard_cache();
+	read_cache_from(index_file ? index_file : get_index_file());
+
+	return 0;
+}
+
+/**
+ * Builds an index that contains just the blobs needed for a 3way merge.
+ */
+static int build_fake_ancestor(const struct am_state *state, const char *index_file)
+{
+	struct child_process cp = CHILD_PROCESS_INIT;
+
+	cp.git_cmd = 1;
+	argv_array_push(&cp.args, "apply");
+	argv_array_pushf(&cp.args, "--build-fake-ancestor=%s", index_file);
+	argv_array_push(&cp.args, am_path(state, "patch"));
+
+	if (run_command(&cp))
+		return -1;
+
+	return 0;
+}
+
+/**
+ * Attempt a threeway merge, using index_path as the temporary index.
+ */
+static int fall_back_threeway(const struct am_state *state, const char *index_path)
+{
+	unsigned char orig_tree[GIT_SHA1_RAWSZ], his_tree[GIT_SHA1_RAWSZ],
+		      our_tree[GIT_SHA1_RAWSZ];
+	const unsigned char *bases[1] = {orig_tree};
+	struct merge_options o;
+	struct commit *result;
+	char *his_tree_name;
+
+	if (get_sha1("HEAD", our_tree) < 0)
+		hashcpy(our_tree, EMPTY_TREE_SHA1_BIN);
+
+	if (build_fake_ancestor(state, index_path))
+		return error("could not build fake ancestor");
+
+	discard_cache();
+	read_cache_from(index_path);
+
+	if (write_index_as_tree(orig_tree, &the_index, index_path, 0, NULL))
+		return error(_("Repository lacks necessary blobs to fall back on 3-way merge."));
+
+	say(state, stdout, _("Using index info to reconstruct a base tree..."));
+
+	if (!state->quiet) {
+		/*
+		 * List paths that needed 3-way fallback, so that the user can
+		 * review them with extra care to spot mismerges.
+		 */
+		struct rev_info rev_info;
+		const char *diff_filter_str = "--diff-filter=AM";
+
+		init_revisions(&rev_info, NULL);
+		rev_info.diffopt.output_format = DIFF_FORMAT_NAME_STATUS;
+		diff_opt_parse(&rev_info.diffopt, &diff_filter_str, 1);
+		add_pending_sha1(&rev_info, "HEAD", our_tree, 0);
+		diff_setup_done(&rev_info.diffopt);
+		run_diff_index(&rev_info, 1);
+	}
+
+	if (run_apply(state, index_path))
+		return error(_("Did you hand edit your patch?\n"
+				"It does not apply to blobs recorded in its index."));
+
+	if (write_index_as_tree(his_tree, &the_index, index_path, 0, NULL))
+		return error("could not write tree");
+
+	say(state, stdout, _("Falling back to patching base and 3-way merge..."));
+
+	discard_cache();
 	read_cache();
 
+	/*
+	 * This is not so wrong. Depending on which base we picked, orig_tree
+	 * may be wildly different from ours, but his_tree has the same set of
+	 * wildly different changes in parts the patch did not touch, so
+	 * recursive ends up canceling them, saying that we reverted all those
+	 * changes.
+	 */
+
+	init_merge_options(&o);
+
+	o.branch1 = "HEAD";
+	his_tree_name = xstrfmt("%.*s", linelen(state->msg), state->msg);
+	o.branch2 = his_tree_name;
+
+	if (state->quiet)
+		o.verbosity = 0;
+
+	if (merge_recursive_generic(&o, our_tree, his_tree, 1, bases, &result)) {
+		free(his_tree_name);
+		return error(_("Failed to merge in the changes."));
+	}
+
+	free(his_tree_name);
 	return 0;
 }
 
@@ -872,6 +998,7 @@ static void am_run(struct am_state *state, int resume)
 
 	while (state->cur <= state->last) {
 		const char *mail = am_path(state, msgnum(state));
+		int apply_status;
 
 		if (!file_exists(mail))
 			goto next;
@@ -889,7 +1016,26 @@ static void am_run(struct am_state *state, int resume)
 
 		say(state, stdout, _("Applying: %.*s"), linelen(state->msg), state->msg);
 
-		if (run_apply(state) < 0) {
+		apply_status = run_apply(state, NULL);
+
+		if (apply_status && state->threeway) {
+			struct strbuf sb = STRBUF_INIT;
+
+			strbuf_addstr(&sb, am_path(state, "patch-merge-index"));
+			apply_status = fall_back_threeway(state, sb.buf);
+			strbuf_release(&sb);
+
+			/*
+			 * Applying the patch to an earlier tree and merging
+			 * the result may have produced the same tree as ours.
+			 */
+			if (!apply_status && !index_has_changes(NULL)) {
+				say(state, stdout, _("No changes -- Patch already applied."));
+				goto next;
+			}
+		}
+
+		if (apply_status) {
 			int advice_amworkdir = 1;
 
 			printf_ln(_("Patch failed at %s %.*s"), msgnum(state),
@@ -1158,6 +1304,8 @@ int cmd_am(int argc, const char **argv, const char *prefix)
 	};
 
 	struct option options[] = {
+		OPT_BOOL('3', "3way", &state.threeway,
+			N_("allow fall back on 3way merging if needed")),
 		OPT__QUIET(&state.quiet, N_("be quiet")),
 		OPT_BOOL('s', "signoff", &state.append_signoff,
 			N_("add a Signed-off-by line to the commit message")),
-- 
2.5.0.rc2.110.gb39b692

[PATCH v6 21/45] builtin-am: implement --rebasing mode

[Paul Tan]

Since 3041c32 (am: --rebasing, 2008-03-04), git-am.sh supported the
--rebasing option, which is used internally by git-rebase to tell git-am
that it is being used for its purpose. It would create the empty file
$state_dir/rebasing to help "completion" scripts tell if the ongoing
operation is am or rebase.

As of 0fbb95d (am: don't call mailinfo if $rebasing, 2012-06-26),
--rebasing also implies --3way as well.

Since a1549e1 (am: return control to caller, for housekeeping,
2013-05-12), git-am.sh would only clean up the state directory when it
is not --rebasing, instead deferring cleanup to git-rebase.sh.

Re-implement the above in builtin/am.c.

Signed-off-by: Paul Tan <pyokagan@gmail.com>
---
 builtin/am.c | 30 ++++++++++++++++++++++++++----
 1 file changed, 26 insertions(+), 4 deletions(-)

diff --git a/builtin/am.c b/builtin/am.c
index 7237fff..3107aba 100644
--- a/builtin/am.c
+++ b/builtin/am.c
@@ -89,6 +89,7 @@ struct am_state {
 	int quiet;
 	int append_signoff;
 	const char *resolvemsg;
+	int rebasing;
 };
 
 /**
@@ -366,6 +367,8 @@ static void am_load(struct am_state *state)
 	read_state_file(&sb, state, "sign", 1);
 	state->append_signoff = !strcmp(sb.buf, "t");
 
+	state->rebasing = !!file_exists(am_path(state, "rebasing"));
+
 	strbuf_release(&sb);
 }
 
@@ -544,18 +547,29 @@ static void am_setup(struct am_state *state, enum patch_format patch_format,
 		die(_("Failed to split patches."));
 	}
 
+	if (state->rebasing)
+		state->threeway = 1;
+
 	write_file(am_path(state, "threeway"), 1, state->threeway ? "t" : "f");
 
 	write_file(am_path(state, "quiet"), 1, state->quiet ? "t" : "f");
 
 	write_file(am_path(state, "sign"), 1, state->append_signoff ? "t" : "f");
 
+	if (state->rebasing)
+		write_file(am_path(state, "rebasing"), 1, "%s", "");
+	else
+		write_file(am_path(state, "applying"), 1, "%s", "");
+
 	if (!get_sha1("HEAD", curr_head)) {
 		write_file(am_path(state, "abort-safety"), 1, "%s", sha1_to_hex(curr_head));
-		update_ref("am", "ORIG_HEAD", curr_head, NULL, 0, UPDATE_REFS_DIE_ON_ERR);
+		if (!state->rebasing)
+			update_ref("am", "ORIG_HEAD", curr_head, NULL, 0,
+					UPDATE_REFS_DIE_ON_ERR);
 	} else {
 		write_file(am_path(state, "abort-safety"), 1, "%s", "");
-		delete_ref("ORIG_HEAD", NULL, 0);
+		if (!state->rebasing)
+			delete_ref("ORIG_HEAD", NULL, 0);
 	}
 
 	/*
@@ -1056,8 +1070,14 @@ next:
 		am_next(state);
 	}
 
-	am_destroy(state);
-	run_command_v_opt(argv_gc_auto, RUN_GIT_CMD);
+	/*
+	 * In rebasing mode, it's up to the caller to take care of
+	 * housekeeping.
+	 */
+	if (!state->rebasing) {
+		am_destroy(state);
+		run_command_v_opt(argv_gc_auto, RUN_GIT_CMD);
+	}
 }
 
 /**
@@ -1326,6 +1346,8 @@ int cmd_am(int argc, const char **argv, const char *prefix)
 		OPT_CMDMODE(0, "abort", &resume,
 			N_("restore the original branch and abort the patching operation."),
 			RESUME_ABORT),
+		OPT_HIDDEN_BOOL(0, "rebasing", &state.rebasing,
+			N_("(internal use for git-rebase)")),
 		OPT_END()
 	};
 
-- 
2.5.0.rc2.110.gb39b692

[PATCH v6 22/45] builtin-am: bypass git-mailinfo when --rebasing

[Paul Tan]

Since 5e835ca (rebase: do not munge commit log message, 2008-04-16),
git am --rebasing no longer gets the commit log message from the patch,
but reads it directly from the commit identified by the "From " header
line.

Since 43c2325 (am: use get_author_ident_from_commit instead of mailinfo
when rebasing, 2010-06-16), git am --rebasing also gets the author name,
email and date directly from the commit.

Since 0fbb95d (am: don't call mailinfo if $rebasing, 2012-06-26), git am
--rebasing does not use git-mailinfo to get the patch body, but rather
generates it directly from the commit itself.

The above 3 commits introduced a separate parse_mail() code path in
git-am.sh's --rebasing mode that bypasses git-mailinfo. Re-implement
this code path in builtin/am.c as parse_mail_rebase().

Signed-off-by: Paul Tan <pyokagan@gmail.com>
---
 builtin/am.c | 134 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++-
 1 file changed, 133 insertions(+), 1 deletion(-)

diff --git a/builtin/am.c b/builtin/am.c
index 3107aba..01f01bf 100644
--- a/builtin/am.c
+++ b/builtin/am.c
@@ -21,6 +21,8 @@
 #include "sequencer.h"
 #include "revision.h"
 #include "merge-recursive.h"
+#include "revision.h"
+#include "log-tree.h"
 
 /**
  * Returns 1 if the file is empty or does not exist, 0 otherwise.
@@ -790,6 +792,129 @@ finish:
 }
 
 /**
+ * Sets commit_id to the commit hash where the mail was generated from.
+ * Returns 0 on success, -1 on failure.
+ */
+static int get_mail_commit_sha1(unsigned char *commit_id, const char *mail)
+{
+	struct strbuf sb = STRBUF_INIT;
+	FILE *fp = xfopen(mail, "r");
+	const char *x;
+
+	if (strbuf_getline(&sb, fp, '\n'))
+		return -1;
+
+	if (!skip_prefix(sb.buf, "From ", &x))
+		return -1;
+
+	if (get_sha1_hex(x, commit_id) < 0)
+		return -1;
+
+	strbuf_release(&sb);
+	fclose(fp);
+	return 0;
+}
+
+/**
+ * Sets state->msg, state->author_name, state->author_email, state->author_date
+ * to the commit's respective info.
+ */
+static void get_commit_info(struct am_state *state, struct commit *commit)
+{
+	const char *buffer, *ident_line, *author_date, *msg;
+	size_t ident_len;
+	struct ident_split ident_split;
+	struct strbuf sb = STRBUF_INIT;
+
+	buffer = logmsg_reencode(commit, NULL, get_commit_output_encoding());
+
+	ident_line = find_commit_header(buffer, "author", &ident_len);
+
+	if (split_ident_line(&ident_split, ident_line, ident_len) < 0) {
+		strbuf_add(&sb, ident_line, ident_len);
+		die(_("invalid ident line: %s"), sb.buf);
+	}
+
+	assert(!state->author_name);
+	if (ident_split.name_begin) {
+		strbuf_add(&sb, ident_split.name_begin,
+			ident_split.name_end - ident_split.name_begin);
+		state->author_name = strbuf_detach(&sb, NULL);
+	} else
+		state->author_name = xstrdup("");
+
+	assert(!state->author_email);
+	if (ident_split.mail_begin) {
+		strbuf_add(&sb, ident_split.mail_begin,
+			ident_split.mail_end - ident_split.mail_begin);
+		state->author_email = strbuf_detach(&sb, NULL);
+	} else
+		state->author_email = xstrdup("");
+
+	author_date = show_ident_date(&ident_split, DATE_NORMAL);
+	strbuf_addstr(&sb, author_date);
+	assert(!state->author_date);
+	state->author_date = strbuf_detach(&sb, NULL);
+
+	assert(!state->msg);
+	msg = strstr(buffer, "\n\n");
+	if (!msg)
+		die(_("unable to parse commit %s"), sha1_to_hex(commit->object.sha1));
+	state->msg = xstrdup(msg + 2);
+	state->msg_len = strlen(state->msg);
+}
+
+/**
+ * Writes `commit` as a patch to the state directory's "patch" file.
+ */
+static void write_commit_patch(const struct am_state *state, struct commit *commit)
+{
+	struct rev_info rev_info;
+	FILE *fp;
+
+	fp = xfopen(am_path(state, "patch"), "w");
+	init_revisions(&rev_info, NULL);
+	rev_info.diff = 1;
+	rev_info.abbrev = 0;
+	rev_info.disable_stdin = 1;
+	rev_info.show_root_diff = 1;
+	rev_info.diffopt.output_format = DIFF_FORMAT_PATCH;
+	rev_info.no_commit_id = 1;
+	DIFF_OPT_SET(&rev_info.diffopt, BINARY);
+	DIFF_OPT_SET(&rev_info.diffopt, FULL_INDEX);
+	rev_info.diffopt.use_color = 0;
+	rev_info.diffopt.file = fp;
+	rev_info.diffopt.close_file = 1;
+	add_pending_object(&rev_info, &commit->object, "");
+	diff_setup_done(&rev_info.diffopt);
+	log_tree_commit(&rev_info, commit);
+}
+
+/**
+ * Like parse_mail(), but parses the mail by looking up its commit ID
+ * directly. This is used in --rebasing mode to bypass git-mailinfo's munging
+ * of patches.
+ *
+ * Will always return 0 as the patch should never be skipped.
+ */
+static int parse_mail_rebase(struct am_state *state, const char *mail)
+{
+	struct commit *commit;
+	unsigned char commit_sha1[GIT_SHA1_RAWSZ];
+
+	if (get_mail_commit_sha1(commit_sha1, mail) < 0)
+		die(_("could not parse %s"), mail);
+
+	commit = lookup_commit_or_die(commit_sha1, mail);
+
+	get_commit_info(state, commit);
+
+	write_commit_patch(state, commit);
+
+	return 0;
+}
+
+/**
  * Applies current patch with git-apply. Returns 0 on success, -1 otherwise. If
  * `index_file` is not NULL, the patch will be applied to that index.
  */
@@ -1021,7 +1146,14 @@ static void am_run(struct am_state *state, int resume)
 			validate_resume_state(state);
 			resume = 0;
 		} else {
-			if (parse_mail(state, mail))
+			int skip;
+
+			if (state->rebasing)
+				skip = parse_mail_rebase(state, mail);
+			else
+				skip = parse_mail(state, mail);
+
+			if (skip)
 				goto next; /* mail should be skipped */
 
 			write_author_script(state);
-- 
2.5.0.rc2.110.gb39b692

[PATCH v6 23/45] builtin-am: handle stray state directory

[Paul Tan]

Should git-am terminate unexpectedly between the point where the state
directory is created, but the "next" and "last" files are not written
yet, a stray state directory will be left behind.

As such, since b141f3c (am: handle stray $dotest directory, 2013-06-15),
git-am.sh explicitly recognizes such a stray directory, and allows the
user to remove it with am --abort.

Re-implement this feature in builtin/am.c.

Signed-off-by: Paul Tan <pyokagan@gmail.com>
---
 builtin/am.c | 17 +++++++++++++++++
 1 file changed, 17 insertions(+)

diff --git a/builtin/am.c b/builtin/am.c
index 01f01bf..398debf 100644
--- a/builtin/am.c
+++ b/builtin/am.c
@@ -1531,6 +1531,23 @@ int cmd_am(int argc, const char **argv, const char *prefix)
 		struct argv_array paths = ARGV_ARRAY_INIT;
 		int i;
 
+		/*
+		 * Handle stray state directory in the independent-run case. In
+		 * the --rebasing case, it is up to the caller to take care of
+		 * stray directories.
+		 */
+		if (file_exists(state.dir) && !state.rebasing) {
+			if (resume == RESUME_ABORT) {
+				am_destroy(&state);
+				am_state_release(&state);
+				return 0;
+			}
+
+			die(_("Stray %s directory found.\n"
+				"Use \"git am --abort\" to remove it."),
+				state.dir);
+		}
+
 		if (resume)
 			die(_("Resolve operation not in progress, we are not resuming."));
 
-- 
2.5.0.rc2.110.gb39b692

[PATCH v6 24/45] builtin-am: implement -u/--utf8

[Paul Tan]

Since d1c5f2a (Add git-am, applymbox replacement., 2005-10-07),
git-am.sh supported the -u,--utf8 option. If set, the -u option will be
passed to git-mailinfo to re-code the commit log message and authorship
in the charset specified by i18n.commitencoding. If unset, the -n option
will be passed to git-mailinfo, which disables the re-encoding.

Since d84029b (--utf8 is now default for 'git-am', 2007-01-08), --utf8
is specified by default in git-am.sh.

Re-implement the above in builtin/am.c.

Signed-off-by: Paul Tan <pyokagan@gmail.com>
---
 builtin/am.c | 11 +++++++++++
 1 file changed, 11 insertions(+)

diff --git a/builtin/am.c b/builtin/am.c
index 398debf..a64a859 100644
--- a/builtin/am.c
+++ b/builtin/am.c
@@ -90,6 +90,7 @@ struct am_state {
 	int threeway;
 	int quiet;
 	int append_signoff;
+	int utf8;
 	const char *resolvemsg;
 	int rebasing;
 };
@@ -108,6 +109,8 @@ static void am_state_init(struct am_state *state, const char *dir)
 	state->prec = 4;
 
 	git_config_get_bool("am.threeway", &state->threeway);
+
+	state->utf8 = 1;
 }
 
 /**
@@ -369,6 +372,9 @@ static void am_load(struct am_state *state)
 	read_state_file(&sb, state, "sign", 1);
 	state->append_signoff = !strcmp(sb.buf, "t");
 
+	read_state_file(&sb, state, "utf8", 1);
+	state->utf8 = !strcmp(sb.buf, "t");
+
 	state->rebasing = !!file_exists(am_path(state, "rebasing"));
 
 	strbuf_release(&sb);
@@ -558,6 +564,8 @@ static void am_setup(struct am_state *state, enum patch_format patch_format,
 
 	write_file(am_path(state, "sign"), 1, state->append_signoff ? "t" : "f");
 
+	write_file(am_path(state, "utf8"), 1, state->utf8 ? "t" : "f");
+
 	if (state->rebasing)
 		write_file(am_path(state, "rebasing"), 1, "%s", "");
 	else
@@ -724,6 +732,7 @@ static int parse_mail(struct am_state *state, const char *mail)
 	cp.out = xopen(am_path(state, "info"), O_WRONLY | O_CREAT, 0777);
 
 	argv_array_push(&cp.args, "mailinfo");
+	argv_array_push(&cp.args, state->utf8 ? "-u" : "-n");
 	argv_array_push(&cp.args, am_path(state, "msg"));
 	argv_array_push(&cp.args, am_path(state, "patch"));
 
@@ -1461,6 +1470,8 @@ int cmd_am(int argc, const char **argv, const char *prefix)
 		OPT__QUIET(&state.quiet, N_("be quiet")),
 		OPT_BOOL('s', "signoff", &state.append_signoff,
 			N_("add a Signed-off-by line to the commit message")),
+		OPT_BOOL('u', "utf8", &state.utf8,
+			N_("recode into utf8 (default)")),
 		OPT_CALLBACK(0, "patch-format", &patch_format, N_("format"),
 			N_("format the patch(es) are in"),
 			parse_opt_patchformat),
-- 
2.5.0.rc2.110.gb39b692

[PATCH v6 25/45] builtin-am: implement -k/--keep, --keep-non-patch

[Paul Tan]

Since d1c5f2a (Add git-am, applymbox replacement., 2005-10-07),
git-am.sh supported the -k/--keep option to pass the -k option to
git-mailsplit.

Since f7e5ea1 (am: learn passing -b to mailinfo, 2012-01-16), git-am.sh
supported the --keep-non-patch option to pass the -b option to
git-mailsplit.

Re-implement these two options in builtin/am.c.

Signed-off-by: Paul Tan <pyokagan@gmail.com>
---
 builtin/am.c | 50 ++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 50 insertions(+)

diff --git a/builtin/am.c b/builtin/am.c
index a64a859..af08a22 100644
--- a/builtin/am.c
+++ b/builtin/am.c
@@ -68,6 +68,12 @@ enum patch_format {
 	PATCH_FORMAT_MBOX
 };
 
+enum keep_type {
+	KEEP_FALSE = 0,
+	KEEP_TRUE,      /* pass -k flag to git-mailinfo */
+	KEEP_NON_PATCH  /* pass -b flag to git-mailinfo */
+};
+
 struct am_state {
 	/* state directory path */
 	char *dir;
@@ -91,6 +97,7 @@ struct am_state {
 	int quiet;
 	int append_signoff;
 	int utf8;
+	int keep; /* enum keep_type */
 	const char *resolvemsg;
 	int rebasing;
 };
@@ -375,6 +382,14 @@ static void am_load(struct am_state *state)
 	read_state_file(&sb, state, "utf8", 1);
 	state->utf8 = !strcmp(sb.buf, "t");
 
+	read_state_file(&sb, state, "keep", 1);
+	if (!strcmp(sb.buf, "t"))
+		state->keep = KEEP_TRUE;
+	else if (!strcmp(sb.buf, "b"))
+		state->keep = KEEP_NON_PATCH;
+	else
+		state->keep = KEEP_FALSE;
+
 	state->rebasing = !!file_exists(am_path(state, "rebasing"));
 
 	strbuf_release(&sb);
@@ -538,6 +553,7 @@ static void am_setup(struct am_state *state, enum patch_format patch_format,
 			const char **paths)
 {
 	unsigned char curr_head[GIT_SHA1_RAWSZ];
+	const char *str;
 
 	if (!patch_format)
 		patch_format = detect_patch_format(paths);
@@ -566,6 +582,22 @@ static void am_setup(struct am_state *state, enum patch_format patch_format,
 
 	write_file(am_path(state, "utf8"), 1, state->utf8 ? "t" : "f");
 
+	switch (state->keep) {
+	case KEEP_FALSE:
+		str = "f";
+		break;
+	case KEEP_TRUE:
+		str = "t";
+		break;
+	case KEEP_NON_PATCH:
+		str = "b";
+		break;
+	default:
+		die("BUG: invalid value for state->keep");
+	}
+
+	write_file(am_path(state, "keep"), 1, "%s", str);
+
 	if (state->rebasing)
 		write_file(am_path(state, "rebasing"), 1, "%s", "");
 	else
@@ -733,6 +765,20 @@ static int parse_mail(struct am_state *state, const char *mail)
 
 	argv_array_push(&cp.args, "mailinfo");
 	argv_array_push(&cp.args, state->utf8 ? "-u" : "-n");
+
+	switch (state->keep) {
+	case KEEP_FALSE:
+		break;
+	case KEEP_TRUE:
+		argv_array_push(&cp.args, "-k");
+		break;
+	case KEEP_NON_PATCH:
+		argv_array_push(&cp.args, "-b");
+		break;
+	default:
+		die("BUG: invalid value for state->keep");
+	}
+
 	argv_array_push(&cp.args, am_path(state, "msg"));
 	argv_array_push(&cp.args, am_path(state, "patch"));
 
@@ -1472,6 +1518,10 @@ int cmd_am(int argc, const char **argv, const char *prefix)
 			N_("add a Signed-off-by line to the commit message")),
 		OPT_BOOL('u', "utf8", &state.utf8,
 			N_("recode into utf8 (default)")),
+		OPT_SET_INT('k', "keep", &state.keep,
+			N_("pass -k flag to git-mailinfo"), KEEP_TRUE),
+		OPT_SET_INT(0, "keep-non-patch", &state.keep,
+			N_("pass -b flag to git-mailinfo"), KEEP_NON_PATCH),
 		OPT_CALLBACK(0, "patch-format", &patch_format, N_("format"),
 			N_("format the patch(es) are in"),
 			parse_opt_patchformat),
-- 
2.5.0.rc2.110.gb39b692

[PATCH v6 26/45] builtin-am: implement --[no-]message-id, am.messageid

[Paul Tan]

Since a078f73 (git-am: add --message-id/--no-message-id, 2014-11-25),
git-am.sh supported the --[no-]message-id options, and the
"am.messageid" setting which specifies the default option.

--[no-]message-id tells git-am whether or not the -m option should be
passed to git-mailinfo.

Re-implement this option in builtin/am.c.

Signed-off-by: Paul Tan <pyokagan@gmail.com>
---
 builtin/am.c | 13 +++++++++++++
 1 file changed, 13 insertions(+)

diff --git a/builtin/am.c b/builtin/am.c
index af08a22..e41a104 100644
--- a/builtin/am.c
+++ b/builtin/am.c
@@ -98,6 +98,7 @@ struct am_state {
 	int append_signoff;
 	int utf8;
 	int keep; /* enum keep_type */
+	int message_id;
 	const char *resolvemsg;
 	int rebasing;
 };
@@ -118,6 +119,8 @@ static void am_state_init(struct am_state *state, const char *dir)
 	git_config_get_bool("am.threeway", &state->threeway);
 
 	state->utf8 = 1;
+
+	git_config_get_bool("am.messageid", &state->message_id);
 }
 
 /**
@@ -390,6 +393,9 @@ static void am_load(struct am_state *state)
 	else
 		state->keep = KEEP_FALSE;
 
+	read_state_file(&sb, state, "messageid", 1);
+	state->message_id = !strcmp(sb.buf, "t");
+
 	state->rebasing = !!file_exists(am_path(state, "rebasing"));
 
 	strbuf_release(&sb);
@@ -598,6 +604,8 @@ static void am_setup(struct am_state *state, enum patch_format patch_format,
 
 	write_file(am_path(state, "keep"), 1, "%s", str);
 
+	write_file(am_path(state, "messageid"), 1, state->message_id ? "t" : "f");
+
 	if (state->rebasing)
 		write_file(am_path(state, "rebasing"), 1, "%s", "");
 	else
@@ -779,6 +787,9 @@ static int parse_mail(struct am_state *state, const char *mail)
 		die("BUG: invalid value for state->keep");
 	}
 
+	if (state->message_id)
+		argv_array_push(&cp.args, "-m");
+
 	argv_array_push(&cp.args, am_path(state, "msg"));
 	argv_array_push(&cp.args, am_path(state, "patch"));
 
@@ -1522,6 +1533,8 @@ int cmd_am(int argc, const char **argv, const char *prefix)
 			N_("pass -k flag to git-mailinfo"), KEEP_TRUE),
 		OPT_SET_INT(0, "keep-non-patch", &state.keep,
 			N_("pass -b flag to git-mailinfo"), KEEP_NON_PATCH),
+		OPT_BOOL('m', "message-id", &state.message_id,
+			N_("pass -m flag to git-mailinfo")),
 		OPT_CALLBACK(0, "patch-format", &patch_format, N_("format"),
 			N_("format the patch(es) are in"),
 			parse_opt_patchformat),
-- 
2.5.0.rc2.110.gb39b692

[PATCH v6 27/45] builtin-am: support --keep-cr, am.keepcr

[Paul Tan]

Since ad2c928 (git-am: Add command line parameter `--keep-cr` passing it
to git-mailsplit, 2010-02-27), git-am.sh supported the --keep-cr option
and would pass it to git-mailsplit.

Since e80d4cb (git-am: Add am.keepcr and --no-keep-cr to override it,
2010-02-27), git-am.sh supported the am.keepcr config setting, which
controls whether --keep-cr is on by default.

Re-implement the above in builtin/am.c.

Signed-off-by: Paul Tan <pyokagan@gmail.com>
---
 builtin/am.c | 29 +++++++++++++++++++++++------
 1 file changed, 23 insertions(+), 6 deletions(-)

diff --git a/builtin/am.c b/builtin/am.c
index e41a104..80f091e 100644
--- a/builtin/am.c
+++ b/builtin/am.c
@@ -504,7 +504,7 @@ done:
  * Splits out individual email patches from `paths`, where each path is either
  * a mbox file or a Maildir. Returns 0 on success, -1 on failure.
  */
-static int split_mail_mbox(struct am_state *state, const char **paths)
+static int split_mail_mbox(struct am_state *state, const char **paths, int keep_cr)
 {
 	struct child_process cp = CHILD_PROCESS_INIT;
 	struct strbuf last = STRBUF_INIT;
@@ -514,6 +514,8 @@ static int split_mail_mbox(struct am_state *state, const char **paths)
 	argv_array_pushf(&cp.args, "-d%d", state->prec);
 	argv_array_pushf(&cp.args, "-o%s", state->dir);
 	argv_array_push(&cp.args, "-b");
+	if (keep_cr)
+		argv_array_push(&cp.args, "--keep-cr");
 	argv_array_push(&cp.args, "--");
 	argv_array_pushv(&cp.args, paths);
 
@@ -538,14 +540,22 @@ static int split_mail_mbox(struct am_state *state, const char **paths)
  * state->cur will be set to the index of the first mail, and state->last will
  * be set to the index of the last mail.
  *
+ * Set keep_cr to 0 to convert all lines ending with \r\n to end with \n, 1
+ * to disable this behavior, -1 to use the default configured setting.
+ *
  * Returns 0 on success, -1 on failure.
  */
 static int split_mail(struct am_state *state, enum patch_format patch_format,
-			const char **paths)
+			const char **paths, int keep_cr)
 {
+	if (keep_cr < 0) {
+		keep_cr = 0;
+		git_config_get_bool("am.keepcr", &keep_cr);
+	}
+
 	switch (patch_format) {
 	case PATCH_FORMAT_MBOX:
-		return split_mail_mbox(state, paths);
+		return split_mail_mbox(state, paths, keep_cr);
 	default:
 		die("BUG: invalid patch_format");
 	}
@@ -556,7 +566,7 @@ static int split_mail(struct am_state *state, enum patch_format patch_format,
  * Setup a new am session for applying patches
  */
 static void am_setup(struct am_state *state, enum patch_format patch_format,
-			const char **paths)
+			const char **paths, int keep_cr)
 {
 	unsigned char curr_head[GIT_SHA1_RAWSZ];
 	const char *str;
@@ -572,7 +582,7 @@ static void am_setup(struct am_state *state, enum patch_format patch_format,
 	if (mkdir(state->dir, 0777) < 0 && errno != EEXIST)
 		die_errno(_("failed to create directory '%s'"), state->dir);
 
-	if (split_mail(state, patch_format, paths) < 0) {
+	if (split_mail(state, patch_format, paths, keep_cr) < 0) {
 		am_destroy(state);
 		die(_("Failed to split patches."));
 	}
@@ -1512,6 +1522,7 @@ enum resume_mode {
 int cmd_am(int argc, const char **argv, const char *prefix)
 {
 	struct am_state state;
+	int keep_cr = -1;
 	int patch_format = PATCH_FORMAT_UNKNOWN;
 	enum resume_mode resume = RESUME_FALSE;
 
@@ -1535,6 +1546,12 @@ int cmd_am(int argc, const char **argv, const char *prefix)
 			N_("pass -b flag to git-mailinfo"), KEEP_NON_PATCH),
 		OPT_BOOL('m', "message-id", &state.message_id,
 			N_("pass -m flag to git-mailinfo")),
+		{ OPTION_SET_INT, 0, "keep-cr", &keep_cr, NULL,
+		  N_("pass --keep-cr flag to git-mailsplit for mbox format"),
+		  PARSE_OPT_NOARG | PARSE_OPT_NONEG, NULL, 1},
+		{ OPTION_SET_INT, 0, "no-keep-cr", &keep_cr, NULL,
+		  N_("do not pass --keep-cr flag to git-mailsplit independent of am.keepcr"),
+		  PARSE_OPT_NOARG | PARSE_OPT_NONEG, NULL, 0},
 		OPT_CALLBACK(0, "patch-format", &patch_format, N_("format"),
 			N_("format the patch(es) are in"),
 			parse_opt_patchformat),
@@ -1632,7 +1649,7 @@ int cmd_am(int argc, const char **argv, const char *prefix)
 				argv_array_push(&paths, mkpath("%s/%s", prefix, argv[i]));
 		}
 
-		am_setup(&state, patch_format, paths.argv);
+		am_setup(&state, patch_format, paths.argv, keep_cr);
 
 		argv_array_clear(&paths);
 	}
-- 
2.5.0.rc2.110.gb39b692

[PATCH v6 28/45] builtin-am: implement --[no-]scissors

[Paul Tan]

Since 017678b (am/mailinfo: Disable scissors processing by default,
2009-08-26), git-am supported the --[no-]scissors option, passing it to
git-mailinfo.

Re-implement support for this option in builtin/am.c.

Since the default setting of --scissors in git-mailinfo can be
configured with mailinfo.scissors (and perhaps through other settings in
the future), to be safe we make an explicit distinction between
SCISSORS_UNSET, SCISSORS_TRUE and SCISSORS_FALSE.

Signed-off-by: Paul Tan <pyokagan@gmail.com>
---
 builtin/am.c | 48 ++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 48 insertions(+)

diff --git a/builtin/am.c b/builtin/am.c
index 80f091e..1f79750 100644
--- a/builtin/am.c
+++ b/builtin/am.c
@@ -74,6 +74,12 @@ enum keep_type {
 	KEEP_NON_PATCH  /* pass -b flag to git-mailinfo */
 };
 
+enum scissors_type {
+	SCISSORS_UNSET = -1,
+	SCISSORS_FALSE = 0,  /* pass --no-scissors to git-mailinfo */
+	SCISSORS_TRUE        /* pass --scissors to git-mailinfo */
+};
+
 struct am_state {
 	/* state directory path */
 	char *dir;
@@ -99,6 +105,7 @@ struct am_state {
 	int utf8;
 	int keep; /* enum keep_type */
 	int message_id;
+	int scissors; /* enum scissors_type */
 	const char *resolvemsg;
 	int rebasing;
 };
@@ -121,6 +128,8 @@ static void am_state_init(struct am_state *state, const char *dir)
 	state->utf8 = 1;
 
 	git_config_get_bool("am.messageid", &state->message_id);
+
+	state->scissors = SCISSORS_UNSET;
 }
 
 /**
@@ -396,6 +405,14 @@ static void am_load(struct am_state *state)
 	read_state_file(&sb, state, "messageid", 1);
 	state->message_id = !strcmp(sb.buf, "t");
 
+	read_state_file(&sb, state, "scissors", 1);
+	if (!strcmp(sb.buf, "t"))
+		state->scissors = SCISSORS_TRUE;
+	else if (!strcmp(sb.buf, "f"))
+		state->scissors = SCISSORS_FALSE;
+	else
+		state->scissors = SCISSORS_UNSET;
+
 	state->rebasing = !!file_exists(am_path(state, "rebasing"));
 
 	strbuf_release(&sb);
@@ -616,6 +633,22 @@ static void am_setup(struct am_state *state, enum patch_format patch_format,
 
 	write_file(am_path(state, "messageid"), 1, state->message_id ? "t" : "f");
 
+	switch (state->scissors) {
+	case SCISSORS_UNSET:
+		str = "";
+		break;
+	case SCISSORS_FALSE:
+		str = "f";
+		break;
+	case SCISSORS_TRUE:
+		str = "t";
+		break;
+	default:
+		die("BUG: invalid value for state->scissors");
+	}
+
+	write_file(am_path(state, "scissors"), 1, "%s", str);
+
 	if (state->rebasing)
 		write_file(am_path(state, "rebasing"), 1, "%s", "");
 	else
@@ -800,6 +833,19 @@ static int parse_mail(struct am_state *state, const char *mail)
 	if (state->message_id)
 		argv_array_push(&cp.args, "-m");
 
+	switch (state->scissors) {
+	case SCISSORS_UNSET:
+		break;
+	case SCISSORS_FALSE:
+		argv_array_push(&cp.args, "--no-scissors");
+		break;
+	case SCISSORS_TRUE:
+		argv_array_push(&cp.args, "--scissors");
+		break;
+	default:
+		die("BUG: invalid value for state->scissors");
+	}
+
 	argv_array_push(&cp.args, am_path(state, "msg"));
 	argv_array_push(&cp.args, am_path(state, "patch"));
 
@@ -1552,6 +1598,8 @@ int cmd_am(int argc, const char **argv, const char *prefix)
 		{ OPTION_SET_INT, 0, "no-keep-cr", &keep_cr, NULL,
 		  N_("do not pass --keep-cr flag to git-mailsplit independent of am.keepcr"),
 		  PARSE_OPT_NOARG | PARSE_OPT_NONEG, NULL, 0},
+		OPT_BOOL('c', "scissors", &state.scissors,
+			N_("strip everything before a scissors line")),
 		OPT_CALLBACK(0, "patch-format", &patch_format, N_("format"),
 			N_("format the patch(es) are in"),
 			parse_opt_patchformat),
-- 
2.5.0.rc2.110.gb39b692

[PATCH v6 29/45] builtin-am: pass git-apply's options to git-apply

[Paul Tan]

git-am.sh recognizes some of git-apply's options, and would pass them to
git-apply:

* --whitespace, since 8c31cb8 (git-am: --whitespace=x option.,
  2006-02-28)

* -C, since 67dad68 (add -C[NUM] to git-am, 2007-02-08)

* -p, since 2092a1f (Teach git-am to pass -p option down to git-apply,
  2007-02-11)

* --directory, since b47dfe9 (git-am: add --directory=<dir> option,
  2009-01-11)

* --reject, since b80da42 (git-am: implement --reject option passed to
  git-apply, 2009-01-23)

* --ignore-space-change, --ignore-whitespace, since 86c91f9 (git apply:
  option to ignore whitespace differences, 2009-08-04)

* --exclude, since 77e9e49 (am: pass exclude down to apply, 2011-08-03)

* --include, since 58725ef (am: support --include option, 2012-03-28)

* --reject, since b80da42 (git-am: implement --reject option passed to
  git-apply, 2009-01-23)

Re-implement support for these options in builtin/am.c.

Signed-off-by: Paul Tan <pyokagan@gmail.com>
---
 builtin/am.c | 45 +++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 45 insertions(+)

diff --git a/builtin/am.c b/builtin/am.c
index 1f79750..9ff0736 100644
--- a/builtin/am.c
+++ b/builtin/am.c
@@ -106,6 +106,7 @@ struct am_state {
 	int keep; /* enum keep_type */
 	int message_id;
 	int scissors; /* enum scissors_type */
+	struct argv_array git_apply_opts;
 	const char *resolvemsg;
 	int rebasing;
 };
@@ -130,6 +131,8 @@ static void am_state_init(struct am_state *state, const char *dir)
 	git_config_get_bool("am.messageid", &state->message_id);
 
 	state->scissors = SCISSORS_UNSET;
+
+	argv_array_init(&state->git_apply_opts);
 }
 
 /**
@@ -142,6 +145,7 @@ static void am_state_release(struct am_state *state)
 	free(state->author_email);
 	free(state->author_date);
 	free(state->msg);
+	argv_array_clear(&state->git_apply_opts);
 }
 
 /**
@@ -413,6 +417,11 @@ static void am_load(struct am_state *state)
 	else
 		state->scissors = SCISSORS_UNSET;
 
+	read_state_file(&sb, state, "apply-opt", 1);
+	argv_array_clear(&state->git_apply_opts);
+	if (sq_dequote_to_argv_array(sb.buf, &state->git_apply_opts) < 0)
+		die(_("could not parse %s"), am_path(state, "apply-opt"));
+
 	state->rebasing = !!file_exists(am_path(state, "rebasing"));
 
 	strbuf_release(&sb);
@@ -587,6 +596,7 @@ static void am_setup(struct am_state *state, enum patch_format patch_format,
 {
 	unsigned char curr_head[GIT_SHA1_RAWSZ];
 	const char *str;
+	struct strbuf sb = STRBUF_INIT;
 
 	if (!patch_format)
 		patch_format = detect_patch_format(paths);
@@ -649,6 +659,9 @@ static void am_setup(struct am_state *state, enum patch_format patch_format,
 
 	write_file(am_path(state, "scissors"), 1, "%s", str);
 
+	sq_quote_argv(&sb, state->git_apply_opts.argv, 0);
+	write_file(am_path(state, "apply-opt"), 1, "%s", sb.buf);
+
 	if (state->rebasing)
 		write_file(am_path(state, "rebasing"), 1, "%s", "");
 	else
@@ -673,6 +686,8 @@ static void am_setup(struct am_state *state, enum patch_format patch_format,
 	write_file(am_path(state, "next"), 1, "%d", state->cur);
 
 	write_file(am_path(state, "last"), 1, "%d", state->last);
+
+	strbuf_release(&sb);
 }
 
 /**
@@ -1060,6 +1075,8 @@ static int run_apply(const struct am_state *state, const char *index_file)
 
 	argv_array_push(&cp.args, "apply");
 
+	argv_array_pushv(&cp.args, state->git_apply_opts.argv);
+
 	if (index_file)
 		argv_array_push(&cp.args, "--cached");
 	else
@@ -1086,6 +1103,7 @@ static int build_fake_ancestor(const struct am_state *state, const char *index_f
 
 	cp.git_cmd = 1;
 	argv_array_push(&cp.args, "apply");
+	argv_array_pushv(&cp.args, state->git_apply_opts.argv);
 	argv_array_pushf(&cp.args, "--build-fake-ancestor=%s", index_file);
 	argv_array_push(&cp.args, am_path(state, "patch"));
 
@@ -1600,9 +1618,36 @@ int cmd_am(int argc, const char **argv, const char *prefix)
 		  PARSE_OPT_NOARG | PARSE_OPT_NONEG, NULL, 0},
 		OPT_BOOL('c', "scissors", &state.scissors,
 			N_("strip everything before a scissors line")),
+		OPT_PASSTHRU_ARGV(0, "whitespace", &state.git_apply_opts, N_("action"),
+			N_("pass it through git-apply"),
+			0),
+		OPT_PASSTHRU_ARGV(0, "ignore-space-change", &state.git_apply_opts, NULL,
+			N_("pass it through git-apply"),
+			PARSE_OPT_NOARG),
+		OPT_PASSTHRU_ARGV(0, "ignore-whitespace", &state.git_apply_opts, NULL,
+			N_("pass it through git-apply"),
+			PARSE_OPT_NOARG),
+		OPT_PASSTHRU_ARGV(0, "directory", &state.git_apply_opts, N_("root"),
+			N_("pass it through git-apply"),
+			0),
+		OPT_PASSTHRU_ARGV(0, "exclude", &state.git_apply_opts, N_("path"),
+			N_("pass it through git-apply"),
+			0),
+		OPT_PASSTHRU_ARGV(0, "include", &state.git_apply_opts, N_("path"),
+			N_("pass it through git-apply"),
+			0),
+		OPT_PASSTHRU_ARGV('C', NULL, &state.git_apply_opts, N_("n"),
+			N_("pass it through git-apply"),
+			0),
+		OPT_PASSTHRU_ARGV('p', NULL, &state.git_apply_opts, N_("num"),
+			N_("pass it through git-apply"),
+			0),
 		OPT_CALLBACK(0, "patch-format", &patch_format, N_("format"),
 			N_("format the patch(es) are in"),
 			parse_opt_patchformat),
+		OPT_PASSTHRU_ARGV(0, "reject", &state.git_apply_opts, NULL,
+			N_("pass it through git-apply"),
+			PARSE_OPT_NOARG),
 		OPT_STRING(0, "resolvemsg", &state.resolvemsg, NULL,
 			N_("override error message when patch failure occurs")),
 		OPT_CMDMODE(0, "continue", &resume,
-- 
2.5.0.rc2.110.gb39b692

[PATCH v6 30/45] builtin-am: implement --ignore-date

[Paul Tan]

Since a79ec62 (git-am: Add --ignore-date option, 2009-01-24), git-am.sh
supported the --ignore-date option, and would use the current timestamp
instead of the one provided in the patch if the option was set.

Re-implement this option in builtin/am.c.

Signed-off-by: Paul Tan <pyokagan@gmail.com>
---
 builtin/am.c | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/builtin/am.c b/builtin/am.c
index 9ff0736..7f068e2 100644
--- a/builtin/am.c
+++ b/builtin/am.c
@@ -108,6 +108,7 @@ struct am_state {
 	int scissors; /* enum scissors_type */
 	struct argv_array git_apply_opts;
 	const char *resolvemsg;
+	int ignore_date;
 	int rebasing;
 };
 
@@ -1219,7 +1220,8 @@ static void do_commit(const struct am_state *state)
 	}
 
 	author = fmt_ident(state->author_name, state->author_email,
-			state->author_date, IDENT_STRICT);
+			state->ignore_date ? NULL : state->author_date,
+			IDENT_STRICT);
 
 	if (commit_tree(state->msg, state->msg_len, tree, parents, commit,
 				author, NULL))
@@ -1662,6 +1664,8 @@ int cmd_am(int argc, const char **argv, const char *prefix)
 		OPT_CMDMODE(0, "abort", &resume,
 			N_("restore the original branch and abort the patching operation."),
 			RESUME_ABORT),
+		OPT_BOOL(0, "ignore-date", &state.ignore_date,
+			N_("use current timestamp for author date")),
 		OPT_HIDDEN_BOOL(0, "rebasing", &state.rebasing,
 			N_("(internal use for git-rebase)")),
 		OPT_END()
-- 
2.5.0.rc2.110.gb39b692

[PATCH v6 31/45] builtin-am: implement --committer-date-is-author-date

[Paul Tan]

Since 3f01ad6 (am: Add --committer-date-is-author-date option,
2009-01-22), git-am.sh implemented the --committer-date-is-author-date
option, which tells git-am to use the timestamp recorded in the email
message as both author and committer date.

Re-implement this option in builtin/am.c.

Signed-off-by: Paul Tan <pyokagan@gmail.com>
---
 builtin/am.c | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/builtin/am.c b/builtin/am.c
index 7f068e2..1080df6 100644
--- a/builtin/am.c
+++ b/builtin/am.c
@@ -108,6 +108,7 @@ struct am_state {
 	int scissors; /* enum scissors_type */
 	struct argv_array git_apply_opts;
 	const char *resolvemsg;
+	int committer_date_is_author_date;
 	int ignore_date;
 	int rebasing;
 };
@@ -1223,6 +1224,10 @@ static void do_commit(const struct am_state *state)
 			state->ignore_date ? NULL : state->author_date,
 			IDENT_STRICT);
 
+	if (state->committer_date_is_author_date)
+		setenv("GIT_COMMITTER_DATE",
+			state->ignore_date ? "" : state->author_date, 1);
+
 	if (commit_tree(state->msg, state->msg_len, tree, parents, commit,
 				author, NULL))
 		die(_("failed to write commit object"));
@@ -1664,6 +1669,9 @@ int cmd_am(int argc, const char **argv, const char *prefix)
 		OPT_CMDMODE(0, "abort", &resume,
 			N_("restore the original branch and abort the patching operation."),
 			RESUME_ABORT),
+		OPT_BOOL(0, "committer-date-is-author-date",
+			&state.committer_date_is_author_date,
+			N_("lie about committer date")),
 		OPT_BOOL(0, "ignore-date", &state.ignore_date,
 			N_("use current timestamp for author date")),
 		OPT_HIDDEN_BOOL(0, "rebasing", &state.rebasing,
-- 
2.5.0.rc2.110.gb39b692

[PATCH v6 32/45] builtin-am: implement -S/--gpg-sign, commit.gpgsign

[Paul Tan]

Since 3b4e395 (am: add the --gpg-sign option, 2014-02-01), git-am.sh
supported the --gpg-sign option, and would pass it to git-commit-tree,
thus GPG-signing the commit object.

Re-implement this option in builtin/am.c.

git-commit-tree would also sign the commit by default if the
commit.gpgsign setting is true. Since we do not run commit-tree, we
re-implement this behavior by handling the commit.gpgsign setting
ourselves.

Helped-by: Stefan Beller <sbeller@google.com>
Signed-off-by: Paul Tan <pyokagan@gmail.com>
---
 builtin/am.c | 11 ++++++++++-
 1 file changed, 10 insertions(+), 1 deletion(-)

diff --git a/builtin/am.c b/builtin/am.c
index 1080df6..3612bb3 100644
--- a/builtin/am.c
+++ b/builtin/am.c
@@ -110,6 +110,7 @@ struct am_state {
 	const char *resolvemsg;
 	int committer_date_is_author_date;
 	int ignore_date;
+	const char *sign_commit;
 	int rebasing;
 };
 
@@ -119,6 +120,8 @@ struct am_state {
  */
 static void am_state_init(struct am_state *state, const char *dir)
 {
+	int gpgsign;
+
 	memset(state, 0, sizeof(*state));
 
 	assert(dir);
@@ -135,6 +138,9 @@ static void am_state_init(struct am_state *state, const char *dir)
 	state->scissors = SCISSORS_UNSET;
 
 	argv_array_init(&state->git_apply_opts);
+
+	if (!git_config_get_bool("commit.gpgsign", &gpgsign))
+		state->sign_commit = gpgsign ? "" : NULL;
 }
 
 /**
@@ -1229,7 +1235,7 @@ static void do_commit(const struct am_state *state)
 			state->ignore_date ? "" : state->author_date, 1);
 
 	if (commit_tree(state->msg, state->msg_len, tree, parents, commit,
-				author, NULL))
+				author, state->sign_commit))
 		die(_("failed to write commit object"));
 
 	reflog_msg = getenv("GIT_REFLOG_ACTION");
@@ -1674,6 +1680,9 @@ int cmd_am(int argc, const char **argv, const char *prefix)
 			N_("lie about committer date")),
 		OPT_BOOL(0, "ignore-date", &state.ignore_date,
 			N_("use current timestamp for author date")),
+		{ OPTION_STRING, 'S', "gpg-sign", &state.sign_commit, N_("key-id"),
+		  N_("GPG-sign commits"),
+		  PARSE_OPT_OPTARG, NULL, (intptr_t) "" },
 		OPT_HIDDEN_BOOL(0, "rebasing", &state.rebasing,
 			N_("(internal use for git-rebase)")),
 		OPT_END()
-- 
2.5.0.rc2.110.gb39b692

[PATCH v6 33/45] builtin-am: invoke post-rewrite hook

[Paul Tan]

Since 96e1948 (rebase: invoke post-rewrite hook, 2010-03-12), git-am.sh
will invoke the post-rewrite hook after it successfully finishes
applying all the queued patches.

To do this, when parsing a mail to extract its patch and metadata, in
--rebasing mode git-am.sh will also store the original commit ID in the
$state_dir/original-commit file. Once it applies and commits the patch,
the original commit ID, and the new commit ID, will be appended to the
$state_dir/rewritten file.

Once all of the queued mail have been processed, git-am.sh will then
invoke the post-rewrite hook with the contents of the
$state_dir/rewritten file.

Re-implement this in builtin/am.c.

Signed-off-by: Paul Tan <pyokagan@gmail.com>
---
 builtin/am.c | 55 +++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 55 insertions(+)

diff --git a/builtin/am.c b/builtin/am.c
index 3612bb3..e99e1ec 100644
--- a/builtin/am.c
+++ b/builtin/am.c
@@ -95,6 +95,9 @@ struct am_state {
 	char *msg;
 	size_t msg_len;
 
+	/* when --rebasing, records the original commit the patch came from */
+	unsigned char orig_commit[GIT_SHA1_RAWSZ];
+
 	/* number of digits in patch filename */
 	int prec;
 
@@ -394,6 +397,11 @@ static void am_load(struct am_state *state)
 
 	read_commit_msg(state);
 
+	if (read_state_file(&sb, state, "original-commit", 1) < 0)
+		hashclr(state->orig_commit);
+	else if (get_sha1_hex(sb.buf, state->orig_commit) < 0)
+		die(_("could not parse %s"), am_path(state, "original-commit"));
+
 	read_state_file(&sb, state, "threeway", 1);
 	state->threeway = !strcmp(sb.buf, "t");
 
@@ -449,6 +457,30 @@ static void am_destroy(const struct am_state *state)
 }
 
 /**
+ * Runs post-rewrite hook. Returns it exit code.
+ */
+static int run_post_rewrite_hook(const struct am_state *state)
+{
+	struct child_process cp = CHILD_PROCESS_INIT;
+	const char *hook = find_hook("post-rewrite");
+	int ret;
+
+	if (!hook)
+		return 0;
+
+	argv_array_push(&cp.args, hook);
+	argv_array_push(&cp.args, "rebase");
+
+	cp.in = xopen(am_path(state, "rewritten"), O_RDONLY);
+	cp.stdout_to_stderr = 1;
+
+	ret = run_command(&cp);
+
+	close(cp.in);
+	return ret;
+}
+
+/**
  * Determines if the file looks like a piece of RFC2822 mail by grabbing all
  * non-indented lines and checking if they look like they begin with valid
  * header field names.
@@ -722,6 +754,9 @@ static void am_next(struct am_state *state)
 	unlink(am_path(state, "author-script"));
 	unlink(am_path(state, "final-commit"));
 
+	hashclr(state->orig_commit);
+	unlink(am_path(state, "original-commit"));
+
 	if (!get_sha1("HEAD", head))
 		write_file(am_path(state, "abort-safety"), 1, "%s", sha1_to_hex(head));
 	else
@@ -1040,6 +1075,8 @@ static void write_commit_patch(const struct am_state *state, struct commit *comm
  * directly. This is used in --rebasing mode to bypass git-mailinfo's munging
  * of patches.
  *
+ * state->orig_commit will be set to the original commit ID.
+ *
  * Will always return 0 as the patch should never be skipped.
  */
 static int parse_mail_rebase(struct am_state *state, const char *mail)
@@ -1056,6 +1093,10 @@ static int parse_mail_rebase(struct am_state *state, const char *mail)
 
 	write_commit_patch(state, commit);
 
+	hashcpy(state->orig_commit, commit_sha1);
+	write_file(am_path(state, "original-commit"), 1, "%s",
+			sha1_to_hex(commit_sha1));
+
 	return 0;
 }
 
@@ -1247,6 +1288,15 @@ static void do_commit(const struct am_state *state)
 
 	update_ref(sb.buf, "HEAD", commit, ptr, 0, UPDATE_REFS_DIE_ON_ERR);
 
+	if (state->rebasing) {
+		FILE *fp = xfopen(am_path(state, "rewritten"), "a");
+
+		assert(!is_null_sha1(state->orig_commit));
+		fprintf(fp, "%s ", sha1_to_hex(state->orig_commit));
+		fprintf(fp, "%s\n", sha1_to_hex(commit));
+		fclose(fp);
+	}
+
 	strbuf_release(&sb);
 }
 
@@ -1355,6 +1405,11 @@ next:
 		am_next(state);
 	}
 
+	if (!is_empty_file(am_path(state, "rewritten"))) {
+		assert(state->rebasing);
+		run_post_rewrite_hook(state);
+	}
+
 	/*
 	 * In rebasing mode, it's up to the caller to take care of
 	 * housekeeping.
-- 
2.5.0.rc2.110.gb39b692

[PATCH v6 34/45] builtin-am: support automatic notes copying

[Paul Tan]

Since eb2151b (rebase: support automatic notes copying, 2010-03-12),
git-am.sh supported automatic notes copying in --rebasing mode by
invoking "git notes copy" once it has finished applying all the patches.

Re-implement this feature in builtin/am.c.

Signed-off-by: Paul Tan <pyokagan@gmail.com>
---
 builtin/am.c | 60 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 60 insertions(+)

diff --git a/builtin/am.c b/builtin/am.c
index e99e1ec..64b467f 100644
--- a/builtin/am.c
+++ b/builtin/am.c
@@ -23,6 +23,7 @@
 #include "merge-recursive.h"
 #include "revision.h"
 #include "log-tree.h"
+#include "notes-utils.h"
 
 /**
  * Returns 1 if the file is empty or does not exist, 0 otherwise.
@@ -481,6 +482,64 @@ static int run_post_rewrite_hook(const struct am_state *state)
 }
 
 /**
+ * Reads the state directory's "rewritten" file, and copies notes from the old
+ * commits listed in the file to their rewritten commits.
+ *
+ * Returns 0 on success, -1 on failure.
+ */
+static int copy_notes_for_rebase(const struct am_state *state)
+{
+	struct notes_rewrite_cfg *c;
+	struct strbuf sb = STRBUF_INIT;
+	const char *invalid_line = _("Malformed input line: '%s'.");
+	const char *msg = "Notes added by 'git rebase'";
+	FILE *fp;
+	int ret = 0;
+
+	assert(state->rebasing);
+
+	c = init_copy_notes_for_rewrite("rebase");
+	if (!c)
+		return 0;
+
+	fp = xfopen(am_path(state, "rewritten"), "r");
+
+	while (!strbuf_getline(&sb, fp, '\n')) {
+		unsigned char from_obj[GIT_SHA1_RAWSZ], to_obj[GIT_SHA1_RAWSZ];
+
+		if (sb.len != GIT_SHA1_HEXSZ * 2 + 1) {
+			ret = error(invalid_line, sb.buf);
+			goto finish;
+		}
+
+		if (get_sha1_hex(sb.buf, from_obj)) {
+			ret = error(invalid_line, sb.buf);
+			goto finish;
+		}
+
+		if (sb.buf[GIT_SHA1_HEXSZ] != ' ') {
+			ret = error(invalid_line, sb.buf);
+			goto finish;
+		}
+
+		if (get_sha1_hex(sb.buf + GIT_SHA1_HEXSZ + 1, to_obj)) {
+			ret = error(invalid_line, sb.buf);
+			goto finish;
+		}
+
+		if (copy_note_for_rewrite(c, from_obj, to_obj))
+			ret = error(_("Failed to copy notes from '%s' to '%s'"),
+					sha1_to_hex(from_obj), sha1_to_hex(to_obj));
+	}
+
+finish:
+	finish_copy_notes_for_rewrite(c, msg);
+	fclose(fp);
+	strbuf_release(&sb);
+	return ret;
+}
+
+/**
  * Determines if the file looks like a piece of RFC2822 mail by grabbing all
  * non-indented lines and checking if they look like they begin with valid
  * header field names.
@@ -1407,6 +1466,7 @@ next:
 
 	if (!is_empty_file(am_path(state, "rewritten"))) {
 		assert(state->rebasing);
+		copy_notes_for_rebase(state);
 		run_post_rewrite_hook(state);
 	}
 
-- 
2.5.0.rc2.110.gb39b692

[PATCH v6 35/45] builtin-am: invoke applypatch-msg hook

[Paul Tan]

Since d1c5f2a (Add git-am, applymbox replacement., 2005-10-07),
git-am.sh will invoke the applypatch-msg hooks just after extracting the
patch message. If the applypatch-msg hook exits with a non-zero status,
git-am.sh abort before even applying the patch to the index.

Re-implement this in builtin/am.c.

Signed-off-by: Paul Tan <pyokagan@gmail.com>
---
 builtin/am.c | 24 ++++++++++++++++++++++++
 1 file changed, 24 insertions(+)

diff --git a/builtin/am.c b/builtin/am.c
index 64b467f..764e955 100644
--- a/builtin/am.c
+++ b/builtin/am.c
@@ -458,6 +458,27 @@ static void am_destroy(const struct am_state *state)
 }
 
 /**
+ * Runs applypatch-msg hook. Returns its exit code.
+ */
+static int run_applypatch_msg_hook(struct am_state *state)
+{
+	int ret;
+
+	assert(state->msg);
+	ret = run_hook_le(NULL, "applypatch-msg", am_path(state, "final-commit"), NULL);
+
+	if (!ret) {
+		free(state->msg);
+		state->msg = NULL;
+		if (read_commit_msg(state) < 0)
+			die(_("'%s' was deleted by the applypatch-msg hook"),
+				am_path(state, "final-commit"));
+	}
+
+	return ret;
+}
+
+/**
  * Runs post-rewrite hook. Returns it exit code.
  */
 static int run_post_rewrite_hook(const struct am_state *state)
@@ -1422,6 +1443,9 @@ static void am_run(struct am_state *state, int resume)
 			write_commit_msg(state);
 		}
 
+		if (run_applypatch_msg_hook(state))
+			exit(1);
+
 		say(state, stdout, _("Applying: %.*s"), linelen(state->msg), state->msg);
 
 		apply_status = run_apply(state, NULL);
-- 
2.5.0.rc2.110.gb39b692

[PATCH v6 36/45] builtin-am: invoke pre-applypatch hook

[Paul Tan]

Since d1c5f2a (Add git-am, applymbox replacement., 2005-10-07),
git-am.sg will invoke the pre-applypatch hook after applying the patch
to the index, but before a commit is made. Should the hook exit with a
non-zero status, git am will exit.

Re-implement this in builtin/am.c.

Signed-off-by: Paul Tan <pyokagan@gmail.com>
---
 builtin/am.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/builtin/am.c b/builtin/am.c
index 764e955..fdba3b0 100644
--- a/builtin/am.c
+++ b/builtin/am.c
@@ -1336,6 +1336,9 @@ static void do_commit(const struct am_state *state)
 	const char *reflog_msg, *author;
 	struct strbuf sb = STRBUF_INIT;
 
+	if (run_hook_le(NULL, "pre-applypatch", NULL))
+		exit(1);
+
 	if (write_cache_as_tree(tree, 0, NULL))
 		die(_("git write-tree failed to write a tree"));
 
-- 
2.5.0.rc2.110.gb39b692

[PATCH v6 37/45] builtin-am: invoke post-applypatch hook

[Paul Tan]

Since d1c5f2a (Add git-am, applymbox replacement., 2005-10-07),
git-am.sh will invoke the post-applypatch hook after the patch is
applied and a commit is made. The exit code of the hook is ignored.

Re-implement this in builtin/am.c.

Signed-off-by: Paul Tan <pyokagan@gmail.com>
---
 builtin/am.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/builtin/am.c b/builtin/am.c
index fdba3b0..638b6d3 100644
--- a/builtin/am.c
+++ b/builtin/am.c
@@ -1380,6 +1380,8 @@ static void do_commit(const struct am_state *state)
 		fclose(fp);
 	}
 
+	run_hook_le(NULL, "post-applypatch", NULL);
+
 	strbuf_release(&sb);
 }
 
-- 
2.5.0.rc2.110.gb39b692

[PATCH v6 38/45] builtin-am: rerere support

[Paul Tan]

git-am.sh will call git-rerere at the following events:

* "git rerere" when a three-way merge fails to record the conflicted
  automerge results. Since 8389b52 (git-rerere: reuse recorded resolve.,
  2006-01-28)

  * Since cb6020b (Teach --[no-]rerere-autoupdate option to merge,
    revert and friends, 2009-12-04), git-am.sh supports the
    --[no-]rerere-autoupdate option as well, and would pass it to
    git-rerere.

* "git rerere" when --resolved, to record the hand resolution. Since
  f131dd4 (rerere: record (or avoid misrecording) resolved, skipped or
  aborted rebase/am, 2006-12-08)

* "git rerere clear" when --skip-ing. Since f131dd4 (rerere: record (or
  avoid misrecording) resolved, skipped or aborted rebase/am,
  2006-12-08)

* "git rerere clear" when --abort-ing. Since 3e5057a (git am --abort,
  2008-07-16)

Re-implement the above in builtin/am.c.

Signed-off-by: Paul Tan <pyokagan@gmail.com>
---
 builtin/am.c | 25 +++++++++++++++++++++++++
 1 file changed, 25 insertions(+)

diff --git a/builtin/am.c b/builtin/am.c
index 638b6d3..89613e0 100644
--- a/builtin/am.c
+++ b/builtin/am.c
@@ -24,6 +24,7 @@
 #include "revision.h"
 #include "log-tree.h"
 #include "notes-utils.h"
+#include "rerere.h"
 
 /**
  * Returns 1 if the file is empty or does not exist, 0 otherwise.
@@ -114,6 +115,7 @@ struct am_state {
 	const char *resolvemsg;
 	int committer_date_is_author_date;
 	int ignore_date;
+	int allow_rerere_autoupdate;
 	const char *sign_commit;
 	int rebasing;
 };
@@ -1314,6 +1316,7 @@ static int fall_back_threeway(const struct am_state *state, const char *index_pa
 		o.verbosity = 0;
 
 	if (merge_recursive_generic(&o, our_tree, his_tree, 1, bases, &result)) {
+		rerere(state->allow_rerere_autoupdate);
 		free(his_tree_name);
 		return error(_("Failed to merge in the changes."));
 	}
@@ -1533,6 +1536,8 @@ static void am_resolve(struct am_state *state)
 		die_user_resolve(state);
 	}
 
+	rerere(0);
+
 	do_commit(state);
 
 	am_next(state);
@@ -1633,12 +1638,29 @@ static int clean_index(const unsigned char *head, const unsigned char *remote)
 }
 
 /**
+ * Resets rerere's merge resolution metadata.
+ */
+static void am_rerere_clear(void)
+{
+	struct string_list merge_rr = STRING_LIST_INIT_DUP;
+	int fd = setup_rerere(&merge_rr, 0);
+
+	if (fd < 0)
+		return;
+
+	rerere_clear(&merge_rr);
+	string_list_clear(&merge_rr, 1);
+}
+
+/**
  * Resume the current am session by skipping the current patch.
  */
 static void am_skip(struct am_state *state)
 {
 	unsigned char head[GIT_SHA1_RAWSZ];
 
+	am_rerere_clear();
+
 	if (get_sha1("HEAD", head))
 		hashcpy(head, EMPTY_TREE_SHA1_BIN);
 
@@ -1696,6 +1718,8 @@ static void am_abort(struct am_state *state)
 		return;
 	}
 
+	am_rerere_clear();
+
 	curr_branch = resolve_refdup("HEAD", 0, curr_head, NULL);
 	has_curr_head = !is_null_sha1(curr_head);
 	if (!has_curr_head)
@@ -1824,6 +1848,7 @@ int cmd_am(int argc, const char **argv, const char *prefix)
 			N_("lie about committer date")),
 		OPT_BOOL(0, "ignore-date", &state.ignore_date,
 			N_("use current timestamp for author date")),
+		OPT_RERERE_AUTOUPDATE(&state.allow_rerere_autoupdate),
 		{ OPTION_STRING, 'S', "gpg-sign", &state.sign_commit, N_("key-id"),
 		  N_("GPG-sign commits"),
 		  PARSE_OPT_OPTARG, NULL, (intptr_t) "" },
-- 
2.5.0.rc2.110.gb39b692

[PATCH v6 39/45] builtin-am: support and auto-detect StGit patches

[Paul Tan]

Since c574e68 (git-am foreign patch support: StGIT support, 2009-05-27),
git-am.sh supported converting StGit patches into RFC2822 mail patches
that can be parsed with git-mailinfo.

Implement this by introducing two functions in builtin/am.c:
stgit_patch_to_mail() and split_mail_conv().

stgit_patch_to_mail() is a callback function for split_mail_conv(), and
contains the logic for converting an StGit patch into an RFC2822 mail
patch.

split_mail_conv() implements the logic to go through each file in the
`paths` list, reading from stdin where specified, and calls the callback
function to write the converted patch to the corresponding output file
in the state directory. This interface should be generic enough to
support other foreign patch formats in the future.

Since 15ced75 (git-am foreign patch support: autodetect some patch
formats, 2009-05-27), git-am.sh is able to auto-detect StGit patches.
Re-implement this in builtin/am.c.

Helped-by: Eric Sunshine <sunshine@sunshineco.com>
Signed-off-by: Paul Tan <pyokagan@gmail.com>
---
 builtin/am.c | 132 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++-
 1 file changed, 131 insertions(+), 1 deletion(-)

diff --git a/builtin/am.c b/builtin/am.c
index 89613e0..101bca3 100644
--- a/builtin/am.c
+++ b/builtin/am.c
@@ -65,9 +65,22 @@ static int linelen(const char *msg)
 	return strchrnul(msg, '\n') - msg;
 }
 
+/**
+ * Returns true if `str` consists of only whitespace, false otherwise.
+ */
+static int str_isspace(const char *str)
+{
+	for (; *str; str++)
+		if (!isspace(*str))
+			return 0;
+
+	return 1;
+}
+
 enum patch_format {
 	PATCH_FORMAT_UNKNOWN = 0,
-	PATCH_FORMAT_MBOX
+	PATCH_FORMAT_MBOX,
+	PATCH_FORMAT_STGIT
 };
 
 enum keep_type {
@@ -612,6 +625,8 @@ static int detect_patch_format(const char **paths)
 {
 	enum patch_format ret = PATCH_FORMAT_UNKNOWN;
 	struct strbuf l1 = STRBUF_INIT;
+	struct strbuf l2 = STRBUF_INIT;
+	struct strbuf l3 = STRBUF_INIT;
 	FILE *fp;
 
 	/*
@@ -637,6 +652,23 @@ static int detect_patch_format(const char **paths)
 		goto done;
 	}
 
+	strbuf_reset(&l2);
+	strbuf_getline_crlf(&l2, fp);
+	strbuf_reset(&l3);
+	strbuf_getline_crlf(&l3, fp);
+
+	/*
+	 * If the second line is empty and the third is a From, Author or Date
+	 * entry, this is likely an StGit patch.
+	 */
+	if (l1.len && !l2.len &&
+		(starts_with(l3.buf, "From:") ||
+		 starts_with(l3.buf, "Author:") ||
+		 starts_with(l3.buf, "Date:"))) {
+		ret = PATCH_FORMAT_STGIT;
+		goto done;
+	}
+
 	if (l1.len && is_mail(fp)) {
 		ret = PATCH_FORMAT_MBOX;
 		goto done;
@@ -677,6 +709,100 @@ static int split_mail_mbox(struct am_state *state, const char **paths, int keep_
 }
 
 /**
+ * Callback signature for split_mail_conv(). The foreign patch should be
+ * read from `in`, and the converted patch (in RFC2822 mail format) should be
+ * written to `out`. Return 0 on success, or -1 on failure.
+ */
+typedef int (*mail_conv_fn)(FILE *out, FILE *in, int keep_cr);
+
+/**
+ * Calls `fn` for each file in `paths` to convert the foreign patch to the
+ * RFC2822 mail format suitable for parsing with git-mailinfo.
+ *
+ * Returns 0 on success, -1 on failure.
+ */
+static int split_mail_conv(mail_conv_fn fn, struct am_state *state,
+			const char **paths, int keep_cr)
+{
+	static const char *stdin_only[] = {"-", NULL};
+	int i;
+
+	if (!*paths)
+		paths = stdin_only;
+
+	for (i = 0; *paths; paths++, i++) {
+		FILE *in, *out;
+		const char *mail;
+		int ret;
+
+		if (!strcmp(*paths, "-"))
+			in = stdin;
+		else
+			in = fopen(*paths, "r");
+
+		if (!in)
+			return error(_("could not open '%s' for reading: %s"),
+					*paths, strerror(errno));
+
+		mail = mkpath("%s/%0*d", state->dir, state->prec, i + 1);
+
+		out = fopen(mail, "w");
+		if (!out)
+			return error(_("could not open '%s' for writing: %s"),
+					mail, strerror(errno));
+
+		ret = fn(out, in, keep_cr);
+
+		fclose(out);
+		fclose(in);
+
+		if (ret)
+			return error(_("could not parse patch '%s'"), *paths);
+	}
+
+	state->cur = 1;
+	state->last = i;
+	return 0;
+}
+
+/**
+ * A split_mail_conv() callback that converts an StGit patch to an RFC2822
+ * message suitable for parsing with git-mailinfo.
+ */
+static int stgit_patch_to_mail(FILE *out, FILE *in, int keep_cr)
+{
+	struct strbuf sb = STRBUF_INIT;
+	int subject_printed = 0;
+
+	while (!strbuf_getline(&sb, in, '\n')) {
+		const char *str;
+
+		if (str_isspace(sb.buf))
+			continue;
+		else if (skip_prefix(sb.buf, "Author:", &str))
+			fprintf(out, "From:%s\n", str);
+		else if (starts_with(sb.buf, "From") || starts_with(sb.buf, "Date"))
+			fprintf(out, "%s\n", sb.buf);
+		else if (!subject_printed) {
+			fprintf(out, "Subject: %s\n", sb.buf);
+			subject_printed = 1;
+		} else {
+			fprintf(out, "\n%s\n", sb.buf);
+			break;
+		}
+	}
+
+	strbuf_reset(&sb);
+	while (strbuf_fread(&sb, 8192, in) > 0) {
+		fwrite(sb.buf, 1, sb.len, out);
+		strbuf_reset(&sb);
+	}
+
+	strbuf_release(&sb);
+	return 0;
+}
+
+/**
  * Splits a list of files/directories into individual email patches. Each path
  * in `paths` must be a file/directory that is formatted according to
  * `patch_format`.
@@ -704,6 +830,8 @@ static int split_mail(struct am_state *state, enum patch_format patch_format,
 	switch (patch_format) {
 	case PATCH_FORMAT_MBOX:
 		return split_mail_mbox(state, paths, keep_cr);
+	case PATCH_FORMAT_STGIT:
+		return split_mail_conv(stgit_patch_to_mail, state, paths, keep_cr);
 	default:
 		die("BUG: invalid patch_format");
 	}
@@ -1751,6 +1879,8 @@ static int parse_opt_patchformat(const struct option *opt, const char *arg, int
 
 	if (!strcmp(arg, "mbox"))
 		*opt_value = PATCH_FORMAT_MBOX;
+	else if (!strcmp(arg, "stgit"))
+		*opt_value = PATCH_FORMAT_STGIT;
 	else
 		return error(_("Invalid value for --patch-format: %s"), arg);
 	return 0;
-- 
2.5.0.rc2.110.gb39b692

[PATCH v6 40/45] builtin-am: support and auto-detect StGit series files

[Paul Tan]

Since c574e68 (git-am foreign patch support: StGIT support, 2009-05-27),
git-am.sh is able to read a single StGit series file and, for each StGit
patch listed in the file, convert the StGit patch into a RFC2822 mail
patch suitable for parsing with git-mailinfo, and queue them in the
state directory for applying.

Since 15ced75 (git-am foreign patch support: autodetect some patch
formats, 2009-05-27), git-am.sh is able to auto-detect StGit series
files by checking to see if the file starts with the string:

	# This series applies on GIT commit

Re-implement the above in builtin/am.c.

Signed-off-by: Paul Tan <pyokagan@gmail.com>
---
 builtin/am.c | 59 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++-
 1 file changed, 58 insertions(+), 1 deletion(-)

diff --git a/builtin/am.c b/builtin/am.c
index 101bca3..01f8a53 100644
--- a/builtin/am.c
+++ b/builtin/am.c
@@ -80,7 +80,8 @@ static int str_isspace(const char *str)
 enum patch_format {
 	PATCH_FORMAT_UNKNOWN = 0,
 	PATCH_FORMAT_MBOX,
-	PATCH_FORMAT_STGIT
+	PATCH_FORMAT_STGIT,
+	PATCH_FORMAT_STGIT_SERIES
 };
 
 enum keep_type {
@@ -652,6 +653,11 @@ static int detect_patch_format(const char **paths)
 		goto done;
 	}
 
+	if (starts_with(l1.buf, "# This series applies on GIT commit")) {
+		ret = PATCH_FORMAT_STGIT_SERIES;
+		goto done;
+	}
+
 	strbuf_reset(&l2);
 	strbuf_getline_crlf(&l2, fp);
 	strbuf_reset(&l3);
@@ -803,6 +809,53 @@ static int stgit_patch_to_mail(FILE *out, FILE *in, int keep_cr)
 }
 
 /**
+ * This function only supports a single StGit series file in `paths`.
+ *
+ * Given an StGit series file, converts the StGit patches in the series into
+ * RFC2822 messages suitable for parsing with git-mailinfo, and queues them in
+ * the state directory.
+ *
+ * Returns 0 on success, -1 on failure.
+ */
+static int split_mail_stgit_series(struct am_state *state, const char **paths,
+					int keep_cr)
+{
+	const char *series_dir;
+	char *series_dir_buf;
+	FILE *fp;
+	struct argv_array patches = ARGV_ARRAY_INIT;
+	struct strbuf sb = STRBUF_INIT;
+	int ret;
+
+	if (!paths[0] || paths[1])
+		return error(_("Only one StGIT patch series can be applied at once"));
+
+	series_dir_buf = xstrdup(*paths);
+	series_dir = dirname(series_dir_buf);
+
+	fp = fopen(*paths, "r");
+	if (!fp)
+		return error(_("could not open '%s' for reading: %s"), *paths,
+				strerror(errno));
+
+	while (!strbuf_getline(&sb, fp, '\n')) {
+		if (*sb.buf == '#')
+			continue; /* skip comment lines */
+
+		argv_array_push(&patches, mkpath("%s/%s", series_dir, sb.buf));
+	}
+
+	fclose(fp);
+	strbuf_release(&sb);
+	free(series_dir_buf);
+
+	ret = split_mail_conv(stgit_patch_to_mail, state, patches.argv, keep_cr);
+
+	argv_array_clear(&patches);
+	return ret;
+}
+
+/**
  * Splits a list of files/directories into individual email patches. Each path
  * in `paths` must be a file/directory that is formatted according to
  * `patch_format`.
@@ -832,6 +885,8 @@ static int split_mail(struct am_state *state, enum patch_format patch_format,
 		return split_mail_mbox(state, paths, keep_cr);
 	case PATCH_FORMAT_STGIT:
 		return split_mail_conv(stgit_patch_to_mail, state, paths, keep_cr);
+	case PATCH_FORMAT_STGIT_SERIES:
+		return split_mail_stgit_series(state, paths, keep_cr);
 	default:
 		die("BUG: invalid patch_format");
 	}
@@ -1881,6 +1936,8 @@ static int parse_opt_patchformat(const struct option *opt, const char *arg, int
 		*opt_value = PATCH_FORMAT_MBOX;
 	else if (!strcmp(arg, "stgit"))
 		*opt_value = PATCH_FORMAT_STGIT;
+	else if (!strcmp(arg, "stgit-series"))
+		*opt_value = PATCH_FORMAT_STGIT_SERIES;
 	else
 		return error(_("Invalid value for --patch-format: %s"), arg);
 	return 0;
-- 
2.5.0.rc2.110.gb39b692

[PATCH v6 41/45] builtin-am: support and auto-detect mercurial patches

[Paul Tan]

Since 0cfd112 (am: preliminary support for hg patches, 2011-08-29),
git-am.sh could convert mercurial patches to an RFC2822 mail patch
suitable for parsing with git-mailinfo, and queue them in the state
directory for application.

Since 15ced75 (git-am foreign patch support: autodetect some patch
formats, 2009-05-27), git-am.sh was able to auto-detect mercurial
patches by checking if the file begins with the line:

	# HG changeset patch

Re-implement the above in builtin/am.c.

Helped-by: Stefan Beller <sbeller@google.com>
Signed-off-by: Paul Tan <pyokagan@gmail.com>
---
 builtin/am.c | 74 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++-
 1 file changed, 73 insertions(+), 1 deletion(-)

diff --git a/builtin/am.c b/builtin/am.c
index 01f8a53..8fe616e 100644
--- a/builtin/am.c
+++ b/builtin/am.c
@@ -81,7 +81,8 @@ enum patch_format {
 	PATCH_FORMAT_UNKNOWN = 0,
 	PATCH_FORMAT_MBOX,
 	PATCH_FORMAT_STGIT,
-	PATCH_FORMAT_STGIT_SERIES
+	PATCH_FORMAT_STGIT_SERIES,
+	PATCH_FORMAT_HG
 };
 
 enum keep_type {
@@ -658,6 +659,11 @@ static int detect_patch_format(const char **paths)
 		goto done;
 	}
 
+	if (!strcmp(l1.buf, "# HG changeset patch")) {
+		ret = PATCH_FORMAT_HG;
+		goto done;
+	}
+
 	strbuf_reset(&l2);
 	strbuf_getline_crlf(&l2, fp);
 	strbuf_reset(&l3);
@@ -856,6 +862,68 @@ static int split_mail_stgit_series(struct am_state *state, const char **paths,
 }
 
 /**
+ * A split_patches_conv() callback that converts a mercurial patch to a RFC2822
+ * message suitable for parsing with git-mailinfo.
+ */
+static int hg_patch_to_mail(FILE *out, FILE *in, int keep_cr)
+{
+	struct strbuf sb = STRBUF_INIT;
+
+	while (!strbuf_getline(&sb, in, '\n')) {
+		const char *str;
+
+		if (skip_prefix(sb.buf, "# User ", &str))
+			fprintf(out, "From: %s\n", str);
+		else if (skip_prefix(sb.buf, "# Date ", &str)) {
+			unsigned long timestamp;
+			long tz, tz2;
+			char *end;
+
+			errno = 0;
+			timestamp = strtoul(str, &end, 10);
+			if (errno)
+				return error(_("invalid timestamp"));
+
+			if (!skip_prefix(end, " ", &str))
+				return error(_("invalid Date line"));
+
+			errno = 0;
+			tz = strtol(str, &end, 10);
+			if (errno)
+				return error(_("invalid timezone offset"));
+
+			if (*end)
+				return error(_("invalid Date line"));
+
+			/*
+			 * mercurial's timezone is in seconds west of UTC,
+			 * however git's timezone is in hours + minutes east of
+			 * UTC. Convert it.
+			 */
+			tz2 = labs(tz) / 3600 * 100 + labs(tz) % 3600 / 60;
+			if (tz > 0)
+				tz2 = -tz2;
+
+			fprintf(out, "Date: %s\n", show_date(timestamp, tz2, DATE_RFC2822));
+		} else if (starts_with(sb.buf, "# ")) {
+			continue;
+		} else {
+			fprintf(out, "\n%s\n", sb.buf);
+			break;
+		}
+	}
+
+	strbuf_reset(&sb);
+	while (strbuf_fread(&sb, 8192, in) > 0) {
+		fwrite(sb.buf, 1, sb.len, out);
+		strbuf_reset(&sb);
+	}
+
+	strbuf_release(&sb);
+	return 0;
+}
+
+/**
  * Splits a list of files/directories into individual email patches. Each path
  * in `paths` must be a file/directory that is formatted according to
  * `patch_format`.
@@ -887,6 +955,8 @@ static int split_mail(struct am_state *state, enum patch_format patch_format,
 		return split_mail_conv(stgit_patch_to_mail, state, paths, keep_cr);
 	case PATCH_FORMAT_STGIT_SERIES:
 		return split_mail_stgit_series(state, paths, keep_cr);
+	case PATCH_FORMAT_HG:
+		return split_mail_conv(hg_patch_to_mail, state, paths, keep_cr);
 	default:
 		die("BUG: invalid patch_format");
 	}
@@ -1938,6 +2008,8 @@ static int parse_opt_patchformat(const struct option *opt, const char *arg, int
 		*opt_value = PATCH_FORMAT_STGIT;
 	else if (!strcmp(arg, "stgit-series"))
 		*opt_value = PATCH_FORMAT_STGIT_SERIES;
+	else if (!strcmp(arg, "hg"))
+		*opt_value = PATCH_FORMAT_HG;
 	else
 		return error(_("Invalid value for --patch-format: %s"), arg);
 	return 0;
-- 
2.5.0.rc2.110.gb39b692

[PATCH v6 42/45] builtin-am: implement -i/--interactive

[Paul Tan]

Since d1c5f2a (Add git-am, applymbox replacement., 2005-10-07),
git-am.sh supported the --interactive mode. After parsing the patch mail
and extracting the patch, commit message and authorship info, an
interactive session will begin that allows the user to choose between:

* applying the patch

* applying the patch and all subsequent patches (by disabling
  interactive mode in subsequent patches)

* skipping the patch

* editing the commit message

Since f89ad67 (Add [v]iew patch in git-am interactive., 2005-10-25),
git-am.sh --interactive also supported viewing the patch to be applied.

When --resolved-ing in --interactive mode, we need to take care to
update the patch with the contents of the index, such that the correct
patch will be displayed when the patch is viewed in interactive mode.

Re-implement the above in builtin/am.c

Signed-off-by: Paul Tan <pyokagan@gmail.com>
---

Notes:
    Can't be tested because even with test_terminal isatty(0) still returns
    false.

 builtin/am.c | 105 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++-
 1 file changed, 104 insertions(+), 1 deletion(-)

diff --git a/builtin/am.c b/builtin/am.c
index 8fe616e..39ea3c7 100644
--- a/builtin/am.c
+++ b/builtin/am.c
@@ -25,6 +25,7 @@
 #include "log-tree.h"
 #include "notes-utils.h"
 #include "rerere.h"
+#include "prompt.h"
 
 /**
  * Returns 1 if the file is empty or does not exist, 0 otherwise.
@@ -119,6 +120,7 @@ struct am_state {
 	int prec;
 
 	/* various operating modes and command line options */
+	int interactive;
 	int threeway;
 	int quiet;
 	int append_signoff;
@@ -1173,7 +1175,7 @@ static void NORETURN die_user_resolve(const struct am_state *state)
 	if (state->resolvemsg) {
 		printf_ln("%s", state->resolvemsg);
 	} else {
-		const char *cmdline = "git am";
+		const char *cmdline = state->interactive ? "git am -i" : "git am";
 
 		printf_ln(_("When you have resolved this problem, run \"%s --continue\"."), cmdline);
 		printf_ln(_("If you prefer to skip this patch, run \"%s --skip\" instead."), cmdline);
@@ -1406,6 +1408,36 @@ static void write_commit_patch(const struct am_state *state, struct commit *comm
 }
 
 /**
+ * Writes the diff of the index against HEAD as a patch to the state
+ * directory's "patch" file.
+ */
+static void write_index_patch(const struct am_state *state)
+{
+	struct tree *tree;
+	unsigned char head[GIT_SHA1_RAWSZ];
+	struct rev_info rev_info;
+	FILE *fp;
+
+	if (!get_sha1_tree("HEAD", head))
+		tree = lookup_tree(head);
+	else
+		tree = lookup_tree(EMPTY_TREE_SHA1_BIN);
+
+	fp = xfopen(am_path(state, "patch"), "w");
+	init_revisions(&rev_info, NULL);
+	rev_info.diff = 1;
+	rev_info.disable_stdin = 1;
+	rev_info.no_commit_id = 1;
+	rev_info.diffopt.output_format = DIFF_FORMAT_PATCH;
+	rev_info.diffopt.use_color = 0;
+	rev_info.diffopt.file = fp;
+	rev_info.diffopt.close_file = 1;
+	add_pending_object(&rev_info, &tree->object, "");
+	diff_setup_done(&rev_info.diffopt);
+	run_diff_index(&rev_info, 1);
+}
+
+/**
  * Like parse_mail(), but parses the mail by looking up its commit ID
  * directly. This is used in --rebasing mode to bypass git-mailinfo's munging
  * of patches.
@@ -1657,6 +1689,65 @@ static void validate_resume_state(const struct am_state *state)
 }
 
 /**
+ * Interactively prompt the user on whether the current patch should be
+ * applied.
+ *
+ * Returns 0 if the user chooses to apply the patch, 1 if the user chooses to
+ * skip it.
+ */
+static int do_interactive(struct am_state *state)
+{
+	assert(state->msg);
+
+	if (!isatty(0))
+		die(_("cannot be interactive without stdin connected to a terminal."));
+
+	for (;;) {
+		const char *reply;
+
+		puts(_("Commit Body is:"));
+		puts("--------------------------");
+		printf("%s", state->msg);
+		puts("--------------------------");
+
+		/*
+		 * TRANSLATORS: Make sure to include [y], [n], [e], [v] and [a]
+		 * in your translation. The program will only accept English
+		 * input at this point.
+		 */
+		reply = git_prompt(_("Apply? [y]es/[n]o/[e]dit/[v]iew patch/[a]ccept all: "), PROMPT_ECHO);
+
+		if (!reply) {
+			continue;
+		} else if (*reply == 'y' || *reply == 'Y') {
+			return 0;
+		} else if (*reply == 'a' || *reply == 'A') {
+			state->interactive = 0;
+			return 0;
+		} else if (*reply == 'n' || *reply == 'N') {
+			return 1;
+		} else if (*reply == 'e' || *reply == 'E') {
+			struct strbuf msg = STRBUF_INIT;
+
+			if (!launch_editor(am_path(state, "final-commit"), &msg, NULL)) {
+				free(state->msg);
+				state->msg = strbuf_detach(&msg, &state->msg_len);
+			}
+			strbuf_release(&msg);
+		} else if (*reply == 'v' || *reply == 'V') {
+			const char *pager = git_pager(1);
+			struct child_process cp = CHILD_PROCESS_INIT;
+
+			if (!pager)
+				pager = "cat";
+			argv_array_push(&cp.args, pager);
+			argv_array_push(&cp.args, am_path(state, "patch"));
+			run_command(&cp);
+		}
+	}
+}
+
+/**
  * Applies all queued mail.
  *
  * If `resume` is true, we are "resuming". The "msg" and authorship fields, as
@@ -1704,6 +1795,9 @@ static void am_run(struct am_state *state, int resume)
 			write_commit_msg(state);
 		}
 
+		if (state->interactive && do_interactive(state))
+			goto next;
+
 		if (run_applypatch_msg_hook(state))
 			exit(1);
 
@@ -1789,10 +1883,17 @@ static void am_resolve(struct am_state *state)
 		die_user_resolve(state);
 	}
 
+	if (state->interactive) {
+		write_index_patch(state);
+		if (do_interactive(state))
+			goto next;
+	}
+
 	rerere(0);
 
 	do_commit(state);
 
+next:
 	am_next(state);
 	am_run(state, 0);
 }
@@ -2037,6 +2138,8 @@ int cmd_am(int argc, const char **argv, const char *prefix)
 	};
 
 	struct option options[] = {
+		OPT_BOOL('i', "interactive", &state.interactive,
+			N_("run interactively")),
 		OPT_BOOL('3', "3way", &state.threeway,
 			N_("allow fall back on 3way merging if needed")),
 		OPT__QUIET(&state.quiet, N_("be quiet")),
-- 
2.5.0.rc2.110.gb39b692

[PATCH v6 43/45] builtin-am: implement legacy -b/--binary option

[Paul Tan]

The -b/--binary option was initially implemented in 087b674 (git-am:
--binary; document --resume and --binary., 2005-11-16). The option will
pass the --binary flag to git-apply to allow it to apply binary patches.

However, in 2b6eef9 (Make apply --binary a no-op., 2006-09-06), --binary
was been made a no-op in git-apply. Following that, since cb3a160
(git-am: ignore --binary option, 2008-08-09), the --binary option in
git-am is ignored as well.

In 6c15a1c (am: officially deprecate -b/--binary option, 2012-03-13),
the --binary option was tweaked to its present behavior: when set, the
message:

	The -b/--binary option has been a no-op for long time, and it
	will be removed. Please do not use it anymore.

will be printed.

Re-implement this in builtin/am.c.

Signed-off-by: Paul Tan <pyokagan@gmail.com>
---
 builtin/am.c | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/builtin/am.c b/builtin/am.c
index 39ea3c7..6a2b887 100644
--- a/builtin/am.c
+++ b/builtin/am.c
@@ -2127,6 +2127,7 @@ enum resume_mode {
 int cmd_am(int argc, const char **argv, const char *prefix)
 {
 	struct am_state state;
+	int binary = -1;
 	int keep_cr = -1;
 	int patch_format = PATCH_FORMAT_UNKNOWN;
 	enum resume_mode resume = RESUME_FALSE;
@@ -2140,6 +2141,8 @@ int cmd_am(int argc, const char **argv, const char *prefix)
 	struct option options[] = {
 		OPT_BOOL('i', "interactive", &state.interactive,
 			N_("run interactively")),
+		OPT_HIDDEN_BOOL('b', "binary", &binary,
+			N_("(historical option -- no-op")),
 		OPT_BOOL('3', "3way", &state.threeway,
 			N_("allow fall back on 3way merging if needed")),
 		OPT__QUIET(&state.quiet, N_("be quiet")),
@@ -2240,6 +2243,10 @@ int cmd_am(int argc, const char **argv, const char *prefix)
 
 	argc = parse_options(argc, argv, prefix, options, usage, 0);
 
+	if (binary >= 0)
+		fprintf_ln(stderr, _("The -b/--binary option has been a no-op for long time, and\n"
+				"it will be removed. Please do not use it anymore."));
+
 	if (read_index_preload(&the_index, NULL) < 0)
 		die(_("failed to read the index"));
 
-- 
2.5.0.rc2.110.gb39b692

[PATCH v6 44/45] builtin-am: check for valid committer ident

[Paul Tan]

When commit_tree() is called, if the user does not have an explicit
committer ident configured, it will attempt to construct a default
committer ident based on the user's and system's info (e.g. gecos field,
hostname etc.) However, if a default committer ident is unable to be
constructed, commit_tree() will die(), but at this point of git-am's
execution, there will already be changes made to the index and work
tree.

This can be confusing to new users, and as such since d64e6b0 (Keep
Porcelainish from failing by broken ident after making changes.,
2006-02-18) git-am.sh will check to see if the committer ident has been
configured, or a default one can be constructed, before even starting to
apply patches.

Re-implement this in builtin/am.c.

Signed-off-by: Paul Tan <pyokagan@gmail.com>
---
 builtin/am.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/builtin/am.c b/builtin/am.c
index 6a2b887..1fe2c65 100644
--- a/builtin/am.c
+++ b/builtin/am.c
@@ -2247,6 +2247,9 @@ int cmd_am(int argc, const char **argv, const char *prefix)
 		fprintf_ln(stderr, _("The -b/--binary option has been a no-op for long time, and\n"
 				"it will be removed. Please do not use it anymore."));
 
+	/* Ensure a valid committer ident can be constructed */
+	git_committer_info(IDENT_STRICT);
+
 	if (read_index_preload(&the_index, NULL) < 0)
 		die(_("failed to read the index"));
 
-- 
2.5.0.rc2.110.gb39b692

[PATCH v6 45/45] builtin-am: remove redirection to git-am.sh

[Paul Tan]

At the beginning of the rewrite of git-am.sh to C, in order to not break
existing test scripts that depended on a functional git-am, a
redirection to git-am.sh was introduced that would activate if the
environment variable _GIT_USE_BUILTIN_AM was not defined.

Now that all of git-am.sh's functionality has been re-implemented in
builtin/am.c, remove this redirection, and retire git-am.sh into
contrib/examples/.

Signed-off-by: Paul Tan <pyokagan@gmail.com>
---
 Makefile                                |  1 -
 builtin/am.c                            | 15 ---------------
 git-am.sh => contrib/examples/git-am.sh |  0
 git.c                                   |  7 +------
 4 files changed, 1 insertion(+), 22 deletions(-)
 rename git-am.sh => contrib/examples/git-am.sh (100%)

diff --git a/Makefile b/Makefile
index f88642a..ec51f03 100644
--- a/Makefile
+++ b/Makefile
@@ -467,7 +467,6 @@ TEST_PROGRAMS_NEED_X =
 # interactive shell sessions without exporting it.
 unexport CDPATH
 
-SCRIPT_SH += git-am.sh
 SCRIPT_SH += git-bisect.sh
 SCRIPT_SH += git-difftool--helper.sh
 SCRIPT_SH += git-filter-branch.sh
diff --git a/builtin/am.c b/builtin/am.c
index 1fe2c65..1116304 100644
--- a/builtin/am.c
+++ b/builtin/am.c
@@ -2222,21 +2222,6 @@ int cmd_am(int argc, const char **argv, const char *prefix)
 		OPT_END()
 	};
 
-	/*
-	 * NEEDSWORK: Once all the features of git-am.sh have been
-	 * re-implemented in builtin/am.c, this preamble can be removed.
-	 */
-	if (!getenv("_GIT_USE_BUILTIN_AM")) {
-		const char *path = mkpath("%s/git-am", git_exec_path());
-
-		if (sane_execvp(path, (char **)argv) < 0)
-			die_errno("could not exec %s", path);
-	} else {
-		prefix = setup_git_directory();
-		trace_repo_setup(prefix);
-		setup_work_tree();
-	}
-
 	git_config(git_default_config, NULL);
 
 	am_state_init(&state, git_path("rebase-apply"));
diff --git a/git-am.sh b/contrib/examples/git-am.sh
similarity index 100%
rename from git-am.sh
rename to contrib/examples/git-am.sh
diff --git a/git.c b/git.c
index 38d9ad5..5feba41 100644
--- a/git.c
+++ b/git.c
@@ -370,12 +370,7 @@ static int run_builtin(struct cmd_struct *p, int argc, const char **argv)
 
 static struct cmd_struct commands[] = {
 	{ "add", cmd_add, RUN_SETUP | NEED_WORK_TREE },
-	/*
-	 * NEEDSWORK: Once the redirection to git-am.sh in builtin/am.c has
-	 * been removed, this entry should be changed to
-	 * RUN_SETUP | NEED_WORK_TREE
-	 */
-	{ "am", cmd_am },
+	{ "am", cmd_am, RUN_SETUP | NEED_WORK_TREE },
 	{ "annotate", cmd_annotate, RUN_SETUP },
 	{ "apply", cmd_apply, RUN_SETUP_GENTLY },
 	{ "archive", cmd_archive },
-- 
2.5.0.rc2.110.gb39b692

Re: [PATCH v6 14/45] builtin-am: implement --abort

[Stefan Beller]

On Sun, Jul 19, 2015 at 9:10 AM, Paul Tan <pyokagan@gmail.com> wrote:
> Since 3e5057a (git am --abort, 2008-07-16), git-am supported the --abort
> option that will rewind HEAD back to the original commit. Re-implement
> this through am_abort().
>
> Since 7b3b7e3 (am --abort: keep unrelated commits since the last failure
> and warn, 2010-12-21), to prevent commits made since the last failure
> from being lost, git-am will not rewind HEAD back to the original
> commit if HEAD moved since the last failure. Re-implement this through
> safe_to_abort().
>
> Signed-off-by: Paul Tan <pyokagan@gmail.com>
> ---
>  builtin/am.c | 102 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++--
>  1 file changed, 99 insertions(+), 3 deletions(-)
>
> diff --git a/builtin/am.c b/builtin/am.c
> index 765844b..8a054ee 100644
> --- a/builtin/am.c
> +++ b/builtin/am.c
> @@ -490,6 +490,8 @@ static int split_mail(struct am_state *state, enum patch_format patch_format,
>  static void am_setup(struct am_state *state, enum patch_format patch_format,
>                         const char **paths)
>  {
> +       unsigned char curr_head[GIT_SHA1_RAWSZ];
> +
>         if (!patch_format)
>                 patch_format = detect_patch_format(paths);
>
> @@ -506,6 +508,14 @@ static void am_setup(struct am_state *state, enum patch_format patch_format,
>                 die(_("Failed to split patches."));
>         }
>
> +       if (!get_sha1("HEAD", curr_head)) {
> +               write_file(am_path(state, "abort-safety"), 1, "%s", sha1_to_hex(curr_head));
> +               update_ref("am", "ORIG_HEAD", curr_head, NULL, 0, UPDATE_REFS_DIE_ON_ERR);
> +       } else {
> +               write_file(am_path(state, "abort-safety"), 1, "%s", "");
> +               delete_ref("ORIG_HEAD", NULL, 0);
> +       }
> +
>         /*
>          * NOTE: Since the "next" and "last" files determine if an am_state
>          * session is in progress, they should be written last.
> @@ -522,6 +532,8 @@ static void am_setup(struct am_state *state, enum patch_format patch_format,
>   */
>  static void am_next(struct am_state *state)
>  {
> +       unsigned char head[GIT_SHA1_RAWSZ];
> +
>         free(state->author_name);
>         state->author_name = NULL;
>
> @@ -538,6 +550,11 @@ static void am_next(struct am_state *state)
>         unlink(am_path(state, "author-script"));
>         unlink(am_path(state, "final-commit"));
>
> +       if (!get_sha1("HEAD", head))
> +               write_file(am_path(state, "abort-safety"), 1, "%s", sha1_to_hex(head));
> +       else
> +               write_file(am_path(state, "abort-safety"), 1, "%s", "");
> +
>         state->cur++;
>         write_file(am_path(state, "next"), 1, "%d", state->cur);
>  }
> @@ -788,10 +805,14 @@ static void am_run(struct am_state *state, int resume)
>         const char *argv_gc_auto[] = {"gc", "--auto", NULL};
>         struct strbuf sb = STRBUF_INIT;
>
> +       unlink(am_path(state, "dirtyindex"));
> +
>         refresh_and_write_cache();
>
> -       if (index_has_changes(&sb))
> +       if (index_has_changes(&sb)) {
> +               write_file(am_path(state, "dirtyindex"), 1, "t");
>                 die(_("Dirty index: cannot apply patches (dirty: %s)"), sb.buf);
> +       }
>
>         strbuf_release(&sb);
>
> @@ -980,6 +1001,74 @@ static void am_skip(struct am_state *state)
>  }
>
>  /**
> + * Returns true if it is safe to reset HEAD to the ORIG_HEAD, false otherwise.
> + *
> + * It is not safe to reset HEAD when:
> + * 1. git-am previously failed because the index was dirty.
> + * 2. HEAD has moved since git-am previously failed.
> + */
> +static int safe_to_abort(const struct am_state *state)
> +{
> +       struct strbuf sb = STRBUF_INIT;
> +       unsigned char abort_safety[GIT_SHA1_RAWSZ], head[GIT_SHA1_RAWSZ];
> +
> +       if (file_exists(am_path(state, "dirtyindex")))
> +               return 0;
> +
> +       if (read_state_file(&sb, state, "abort-safety", 1) > 0) {
> +               if (get_sha1_hex(sb.buf, abort_safety))
> +                       die(_("could not parse %s"), am_path(state, "abort_safety"));
> +       } else
> +               hashclr(abort_safety);
> +
> +       if (get_sha1("HEAD", head))
> +               hashclr(head);
> +
> +       if (!hashcmp(head, abort_safety))
> +               return 1;
> +
> +       error(_("You seem to have moved HEAD since the last 'am' failure.\n"
> +               "Not rewinding to ORIG_HEAD"));
> +
> +       return 0;
> +}
> +
> +/**
> + * Aborts the current am session if it is safe to do so.
> + */
> +static void am_abort(struct am_state *state)
> +{
> +       unsigned char curr_head[GIT_SHA1_RAWSZ], orig_head[GIT_SHA1_RAWSZ];
> +       int has_curr_head, has_orig_head;
> +       const char *curr_branch;
> +
> +       if (!safe_to_abort(state)) {
> +               am_destroy(state);
> +               return;
> +       }
> +
> +       curr_branch = resolve_refdup("HEAD", 0, curr_head, NULL);
> +       has_curr_head = !is_null_sha1(curr_head);
> +       if (!has_curr_head)
> +               hashcpy(curr_head, EMPTY_TREE_SHA1_BIN);
> +
> +       has_orig_head = !get_sha1("ORIG_HEAD", orig_head);
> +       if (!has_orig_head)
> +               hashcpy(orig_head, EMPTY_TREE_SHA1_BIN);
> +
> +       clean_index(curr_head, orig_head);
> +
> +       if (has_orig_head)
> +               update_ref("am --abort", "HEAD", orig_head,
> +                               has_curr_head ? curr_head : NULL, 0,
> +                               UPDATE_REFS_DIE_ON_ERR);
> +       else if (curr_branch)
> +               delete_ref(curr_branch, NULL, REF_NODEREF);
> +
> +       am_destroy(state);

free(curr_branch) here?

> +}
> +
> +/**
>   * parse_options() callback that validates and sets opt->value to the
>   * PATCH_FORMAT_* enum value corresponding to `arg`.
>   */
> @@ -998,7 +1087,8 @@ enum resume_mode {
>         RESUME_FALSE = 0,
>         RESUME_APPLY,
>         RESUME_RESOLVED,
> -       RESUME_SKIP
> +       RESUME_SKIP,
> +       RESUME_ABORT
>  };
>
>  int cmd_am(int argc, const char **argv, const char *prefix)
> @@ -1009,7 +1099,7 @@ int cmd_am(int argc, const char **argv, const char *prefix)
>
>         const char * const usage[] = {
>                 N_("git am [options] [(<mbox>|<Maildir>)...]"),
> -               N_("git am [options] (--continue | --skip)"),
> +               N_("git am [options] (--continue | --skip | --abort)"),
>                 NULL
>         };
>
> @@ -1026,6 +1116,9 @@ int cmd_am(int argc, const char **argv, const char *prefix)
>                 OPT_CMDMODE(0, "skip", &resume,
>                         N_("skip the current patch"),
>                         RESUME_SKIP),
> +               OPT_CMDMODE(0, "abort", &resume,
> +                       N_("restore the original branch and abort the patching operation."),
> +                       RESUME_ABORT),
>                 OPT_END()
>         };
>
> @@ -1090,6 +1183,9 @@ int cmd_am(int argc, const char **argv, const char *prefix)
>         case RESUME_SKIP:
>                 am_skip(&state);
>                 break;
> +       case RESUME_ABORT:
> +               am_abort(&state);
> +               break;
>         default:
>                 die("BUG: invalid resume value");
>         }
> --
> 2.5.0.rc2.110.gb39b692
>