[PATCH 0/2] CHERRY_PICK_HEAD

[PATCH 0/2] CHERRY_PICK_HEAD

[Jay Soffian]

Re-roll of http://thread.gmane.org/gmane.comp.version-control.git/166878

If not ready for inclusion, hopefully very close.

Jay Soffian (2):
  Introduce CHERRY_PICK_HEAD
  Teach commit about CHERRY_PICK_HEAD

 Documentation/git-cherry-pick.txt      |   19 +++++
 Documentation/git-commit.txt           |    7 +-
 Documentation/revisions.txt            |    5 +-
 branch.c                               |    1 +
 builtin/commit.c                       |  136 ++++++++++++++++++++++----------
 builtin/merge.c                        |    7 ++
 builtin/revert.c                       |   68 ++++------------
 contrib/completion/git-completion.bash |    2 +
 t/t3507-cherry-pick-conflict.sh        |   22 +++++-
 t/t7509-commit.sh                      |   29 +++++++
 wt-status.c                            |    4 +-
 wt-status.h                            |    8 ++-
 12 files changed, 204 insertions(+), 104 deletions(-)

-- 
1.7.4.1.28.gd46b3

[PATCH 1/2] Introduce CHERRY_PICK_HEAD

[Jay Soffian]

When a cherry-pick conflicts git advises to use:

 $ git commit -c <original commit id>

to preserve the original commit message and authorship. Instead, let's
record the original commit id in CHERRY_PICK_HEAD and advise to use:

  $ git commit -c CHERRY_PICK_HEAD

In the next commit, we teach git to handle the '-c CHERRY_PICK_HEAD'
part. Note that wWe record CHERRY_PICK_HEAD even in the case where there
are no conflicts so that we may use it to communicate authorship to
commit; this will then allow us to remove set_author_ident_env from
revert.c.

Contributions-by: Jonathan Nieder <jrnieder@gmail.com>
Signed-off-by: Jay Soffian <jaysoffian@gmail.com>
---
 Documentation/git-cherry-pick.txt |   19 +++++++++++++++++++
 Documentation/revisions.txt       |    5 ++++-
 branch.c                          |    1 +
 builtin/commit.c                  |    1 +
 builtin/merge.c                   |    7 +++++++
 builtin/revert.c                  |   20 ++++++++++++++++++--
 t/t3507-cherry-pick-conflict.sh   |   22 +++++++++++++++++++++-
 7 files changed, 71 insertions(+), 4 deletions(-)

diff --git a/Documentation/git-cherry-pick.txt b/Documentation/git-cherry-pick.txt
index 749d68a..5d85daa 100644
--- a/Documentation/git-cherry-pick.txt
+++ b/Documentation/git-cherry-pick.txt
@@ -16,6 +16,25 @@ Given one or more existing commits, apply the change each one
 introduces, recording a new commit for each.  This requires your
 working tree to be clean (no modifications from the HEAD commit).
 
+When it is not obvious how to apply a change, the following
+happens:
+
+1. The current branch and `HEAD` pointer stay at the last commit
+   successfully made.
+2. The `CHERRY_PICK_HEAD` ref is set to point at the commit that
+   introduced the change that is difficult to apply.
+3. Paths in which the change applied cleanly are updated both
+   in the index file and in your working tree.
+4. For conflicting paths, the index file records up to three
+   versions, as described in the "TRUE MERGE" section of
+   linkgit:git-merge[1].  The working tree files will include
+   a description of the conflict bracketed by the usual
+   conflict markers `<<<<<<<` and `>>>>>>>`.
+5. No other modifications are made.
+
+See linkgit:git-merge[1] for some hints on resolving such
+conflicts.
+
 OPTIONS
 -------
 <commit>...::
diff --git a/Documentation/revisions.txt b/Documentation/revisions.txt
index 9e92734..04fceee 100644
--- a/Documentation/revisions.txt
+++ b/Documentation/revisions.txt
@@ -25,7 +25,8 @@ blobs contained in a commit.
   first match in the following rules:
 
   . if `$GIT_DIR/<name>` exists, that is what you mean (this is usually
-    useful only for `HEAD`, `FETCH_HEAD`, `ORIG_HEAD` and `MERGE_HEAD`);
+    useful only for `HEAD`, `FETCH_HEAD`, `ORIG_HEAD`, `MERGE_HEAD`
+    and `CHERRY_PICK_HEAD`);
 
   . otherwise, `refs/<name>` if exists;
 
@@ -46,6 +47,8 @@ you can change the tip of the branch back to the state before you ran
 them easily.
 MERGE_HEAD records the commit(s) you are merging into your branch
 when you run 'git merge'.
+CHERRY_PICK_HEAD records the commit you are cherry-picking
+when you run 'git cherry-pick'.
 +
 Note that any of the `refs/*` cases above may come either from
 the `$GIT_DIR/refs` directory or from the `$GIT_DIR/packed-refs` file.
diff --git a/branch.c b/branch.c
index 93dc866..dc23e95 100644
--- a/branch.c
+++ b/branch.c
@@ -217,6 +217,7 @@ void create_branch(const char *head,
 
 void remove_branch_state(void)
 {
+	unlink(git_path("CHERRY_PICK_HEAD"));
 	unlink(git_path("MERGE_HEAD"));
 	unlink(git_path("MERGE_RR"));
 	unlink(git_path("MERGE_MSG"));
diff --git a/builtin/commit.c b/builtin/commit.c
index 03cff5a..0def540 100644
--- a/builtin/commit.c
+++ b/builtin/commit.c
@@ -1424,6 +1424,7 @@ int cmd_commit(int argc, const char **argv, const char *prefix)
 		die("cannot update HEAD ref");
 	}
 
+	unlink(git_path("CHERRY_PICK_HEAD"));
 	unlink(git_path("MERGE_HEAD"));
 	unlink(git_path("MERGE_MSG"));
 	unlink(git_path("MERGE_MODE"));
diff --git a/builtin/merge.c b/builtin/merge.c
index 9403747..454dad2 100644
--- a/builtin/merge.c
+++ b/builtin/merge.c
@@ -971,6 +971,13 @@ int cmd_merge(int argc, const char **argv, const char *prefix)
 		else
 			die("You have not concluded your merge (MERGE_HEAD exists).");
 	}
+	if (file_exists(git_path("CHERRY_PICK_HEAD"))) {
+		if (advice_resolve_conflict)
+			die("You have not concluded your cherry-pick (CHERRY_PICK_HEAD exists).\n"
+			    "Please, commit your changes before you can merge.");
+		else
+			die("You have not concluded your cherry-pick (CHERRY_PICK_HEAD exists).");
+	}
 	resolve_undo_clear();
 
 	if (verbosity < 0)
diff --git a/builtin/revert.c b/builtin/revert.c
index dc1b702..cced2e4 100644
--- a/builtin/revert.c
+++ b/builtin/revert.c
@@ -248,6 +248,22 @@ static void set_author_ident_env(const char *message)
 			sha1_to_hex(commit->object.sha1));
 }
 
+static void write_cherry_pick_head(void)
+{
+	int fd;
+	struct strbuf buf = STRBUF_INIT;
+
+	strbuf_addf(&buf, "%s\n", sha1_to_hex(commit->object.sha1));
+
+	fd = open(git_path("CHERRY_PICK_HEAD"), O_WRONLY | O_CREAT, 0666);
+	if (fd < 0)
+		die_errno("Could not open '%s' for writing",
+			  git_path("CHERRY_PICK_HEAD"));
+	if (write_in_full(fd, buf.buf, buf.len) != buf.len || close(fd))
+		die_errno("Could not write to '%s'", git_path("CHERRY_PICK_HEAD"));
+	strbuf_release(&buf);
+}
+
 static void advise(const char *advice, ...)
 {
 	va_list params;
@@ -270,8 +286,7 @@ static void print_advice(void)
 	advise("with 'git add <paths>' or 'git rm <paths>'");
 
 	if (action == CHERRY_PICK)
-		advise("and commit the result with 'git commit -c %s'",
-		       find_unique_abbrev(commit->object.sha1, DEFAULT_ABBREV));
+		advise("and commit the result with 'git commit -c CHERRY_PICK_HEAD'");
 }
 
 static void write_message(struct strbuf *msgbuf, const char *filename)
@@ -504,6 +519,7 @@ static int do_pick_commit(void)
 			strbuf_addstr(&msgbuf, sha1_to_hex(commit->object.sha1));
 			strbuf_addstr(&msgbuf, ")\n");
 		}
+		write_cherry_pick_head();
 	}
 
 	if (!strategy || !strcmp(strategy, "recursive") || action == REVERT) {
diff --git a/t/t3507-cherry-pick-conflict.sh b/t/t3507-cherry-pick-conflict.sh
index 607bf25..fd569c8 100755
--- a/t/t3507-cherry-pick-conflict.sh
+++ b/t/t3507-cherry-pick-conflict.sh
@@ -11,6 +11,12 @@ test_description='test cherry-pick and revert with conflicts
 
 . ./test-lib.sh
 
+test_cmp_rev () {
+	git rev-parse --verify "$1" >expect.rev &&
+	git rev-parse --verify "$2" >actual.rev &&
+	test_cmp expect.rev actual.rev
+}
+
 test_expect_success setup '
 
 	echo unrelated >unrelated &&
@@ -51,13 +57,27 @@ test_expect_success 'advice from failed cherry-pick' "
 	error: could not apply \$picked... picked
 	hint: after resolving the conflicts, mark the corrected paths
 	hint: with 'git add <paths>' or 'git rm <paths>'
-	hint: and commit the result with 'git commit -c \$picked'
+	hint: and commit the result with 'git commit -c CHERRY_PICK_HEAD'
 	EOF
 	test_must_fail git cherry-pick picked 2>actual &&
 
 	test_cmp expected actual
 "
 
+test_expect_success 'failed cherry-pick sets CHERRY_PICK_HEAD' '
+
+	git checkout -f initial^0 &&
+	git read-tree -u --reset HEAD &&
+	git clean -d -f -f -q -x &&
+
+	git update-index --refresh &&
+	git diff-index --exit-code HEAD &&
+
+	test_must_fail git cherry-pick picked &&
+
+	test_cmp_rev picked CHERRY_PICK_HEAD
+'
+
 test_expect_success 'failed cherry-pick produces dirty index' '
 
 	git checkout -f initial^0 &&
-- 
1.7.4.1.28.gd46b3

[PATCH 2/2] Teach commit about CHERRY_PICK_HEAD

[Jay Soffian]

Previously the user was advised to use commit -c CHERRY_PICK_HEAD after
a conflicting cherry-pick. While this would preserve the original
commit's authorship, it would sadly discard cherry-pick's carefully
crafted MERGE_MSG (which contains the list of conflicts as well as the
original commit-id in the case of cherry-pick -x).

On the other hand, if a bare 'commit' were performed, it would preserve
the MERGE_MSG while resetting the authorship.

In other words, there was no way to simultaneously take the authorship
from CHERRY_PICK_HEAD and the commit message from MERGE_MSG.

This change fixes that situation. A bare 'commit' will now take the
authorship from CHERRY_PICK_HEAD and the commit message from MERGE_MSG.
If the user wishes to reset authorship, that must now be done explicitly
via --reset-author.

A side-benefit of passing commit authorship along this way is that we
can eliminate redundant authorship parsing code from revert.c.

A couple minor points:

* While we're at it, we update git-completion.bash to be
  CHERRY_PICK_HEAD aware.

* We remove a unused import from revert.c

Signed-off-by: Jay Soffian <jaysoffian@gmail.com>
---
 Documentation/git-commit.txt           |    7 +-
 builtin/commit.c                       |  137 +++++++++++++++++++++----------
 builtin/revert.c                       |   56 +-------------
 contrib/completion/git-completion.bash |    2 +
 t/t3507-cherry-pick-conflict.sh        |    2 +-
 t/t7509-commit.sh                      |   29 +++++++
 wt-status.c                            |    4 +-
 wt-status.h                            |    8 ++-
 8 files changed, 139 insertions(+), 106 deletions(-)

diff --git a/Documentation/git-commit.txt b/Documentation/git-commit.txt
index b586c0f..fd6a1f7 100644
--- a/Documentation/git-commit.txt
+++ b/Documentation/git-commit.txt
@@ -84,9 +84,10 @@ OPTIONS
 	linkgit:git-rebase[1] for details.
 
 --reset-author::
-	When used with -C/-c/--amend options, declare that the
-	authorship of the resulting commit now belongs of the committer.
-	This also renews the author timestamp.
+	When used with -C/-c/--amend options, or when committing after a
+	a conflicting cherry-pick, declare that the authorship of the
+	resulting commit now belongs of the committer. This also renews
+	the author timestamp.
 
 --short::
 	When doing a dry-run, give the output in the short-format. See
diff --git a/builtin/commit.c b/builtin/commit.c
index 0def540..9d8ad8e 100644
--- a/builtin/commit.c
+++ b/builtin/commit.c
@@ -56,8 +56,10 @@ static const char empty_amend_advice[] =
 
 static unsigned char head_sha1[20];
 
-static char *use_message_buffer;
+static const char *use_message_buffer;
 static const char commit_editmsg[] = "COMMIT_EDITMSG";
+static const char cherry_pick_head[] = "CHERRY_PICK_HEAD";
+static const char merge_head[] = "MERGE_HEAD";
 static struct lock_file index_lock; /* real index */
 static struct lock_file false_lock; /* used only for partial commits */
 static enum {
@@ -68,6 +70,7 @@ static enum {
 
 static const char *logfile, *force_author;
 static const char *template_file;
+static const char *author_message, *author_message_buffer;
 static char *edit_message, *use_message;
 static char *fixup_message, *squash_message;
 static int all, edit_flag, also, interactive, only, amend, signoff;
@@ -88,7 +91,8 @@ static enum {
 } cleanup_mode;
 static char *cleanup_arg;
 
-static int use_editor = 1, initial_commit, in_merge, include_status = 1;
+static enum commit_whence whence;
+static int use_editor = 1, initial_commit, include_status = 1;
 static int show_ignored_in_status;
 static const char *only_include_assumed;
 static struct strbuf message;
@@ -163,6 +167,36 @@ static struct option builtin_commit_options[] = {
 	OPT_END()
 };
 
+static void determine_whence(struct wt_status *s)
+{
+	if (file_exists(git_path(merge_head)))
+		whence = FROM_MERGE;
+	else if (file_exists(git_path(cherry_pick_head)))
+		whence = FROM_CHERRY_PICK;
+	else
+		whence = FROM_COMMIT;
+	if (s)
+		s->whence = whence;
+}
+
+static const char *whence_s(void)
+{
+	char *s = "";
+
+	switch (whence) {
+	case FROM_COMMIT:
+		break;
+	case FROM_MERGE:
+		s = "merge";
+		break;
+	case FROM_CHERRY_PICK:
+		s = "cherry-pick";
+		break;
+	}
+
+	return s;
+}
+
 static void rollback_index_files(void)
 {
 	switch (commit_style) {
@@ -378,8 +412,8 @@ static char *prepare_index(int argc, const char **argv, const char *prefix, int
 	 */
 	commit_style = COMMIT_PARTIAL;
 
-	if (in_merge)
-		die("cannot do a partial commit during a merge.");
+	if (whence != FROM_COMMIT)
+		die("cannot do a partial commit during a %s.", whence_s());
 
 	memset(&partial, 0, sizeof(partial));
 	partial.strdup_strings = 1;
@@ -469,18 +503,18 @@ static void determine_author_info(struct strbuf *author_ident)
 	email = getenv("GIT_AUTHOR_EMAIL");
 	date = getenv("GIT_AUTHOR_DATE");
 
-	if (use_message && !renew_authorship) {
+	if (author_message) {
 		const char *a, *lb, *rb, *eol;
 
-		a = strstr(use_message_buffer, "\nauthor ");
+		a = strstr(author_message_buffer, "\nauthor ");
 		if (!a)
-			die("invalid commit: %s", use_message);
+			die("invalid commit: %s", author_message);
 
 		lb = strchrnul(a + strlen("\nauthor "), '<');
 		rb = strchrnul(lb, '>');
 		eol = strchrnul(rb, '\n');
 		if (!*lb || !*rb || !*eol)
-			die("invalid commit: %s", use_message);
+			die("invalid commit: %s", author_message);
 
 		if (lb == a + strlen("\nauthor "))
 			/* \nauthor <foo@example.com> */
@@ -644,7 +678,7 @@ static int prepare_to_commit(const char *index_file, const char *prefix,
 	 * This final case does not modify the template message,
 	 * it just sets the argument to the prepare-commit-msg hook.
 	 */
-	else if (in_merge)
+	else if (whence == FROM_MERGE)
 		hook_arg1 = "merge";
 
 	if (squash_message) {
@@ -694,16 +728,18 @@ static int prepare_to_commit(const char *index_file, const char *prefix,
 	strbuf_addstr(&committer_ident, git_committer_info(0));
 	if (use_editor && include_status) {
 		char *ai_tmp, *ci_tmp;
-		if (in_merge)
+		if (whence != FROM_COMMIT)
 			fprintf(fp,
 				"#\n"
-				"# It looks like you may be committing a MERGE.\n"
+				"# It looks like you may be committing a %s.\n"
 				"# If this is not correct, please remove the file\n"
 				"#	%s\n"
 				"# and try again.\n"
 				"#\n",
-				git_path("MERGE_HEAD"));
-
+				whence_s(),
+				git_path(whence == FROM_MERGE
+					 ? merge_head
+					 : cherry_pick_head));
 		fprintf(fp,
 			"\n"
 			"# Please enter the commit message for your changes.");
@@ -766,7 +802,7 @@ static int prepare_to_commit(const char *index_file, const char *prefix,
 
 	fclose(fp);
 
-	if (!commitable && !in_merge && !allow_empty &&
+	if (!commitable && whence != FROM_MERGE && !allow_empty &&
 	    !(amend && is_a_merge(head_sha1))) {
 		run_status(stdout, index_file, prefix, 0, s);
 		if (amend)
@@ -898,6 +934,27 @@ static void handle_untracked_files_arg(struct wt_status *s)
 		die("Invalid untracked files mode '%s'", untracked_files_arg);
 }
 
+static const char *read_commit_message(const char *name) {
+	const char *out_enc, *out;
+	struct commit *commit;
+
+	commit = lookup_commit_reference_by_name(name);
+	if (!commit)
+		die("could not lookup commit %s", name);
+	out_enc = get_commit_output_encoding();
+	out = logmsg_reencode(commit, out_enc);
+
+	/*
+	 * If we failed to reencode the buffer, just copy it
+	 * byte for byte so the user can try to fix it up.
+	 * This also handles the case where input and output
+	 * encodings are identical.
+	 */
+	if (out == NULL)
+		out = xstrdup(commit->buffer);
+	return out;
+}
+
 static int parse_and_validate_options(int argc, const char *argv[],
 				      const char * const usage[],
 				      const char *prefix,
@@ -927,8 +984,8 @@ static int parse_and_validate_options(int argc, const char *argv[],
 	/* Sanity check options */
 	if (amend && initial_commit)
 		die("You have nothing to amend.");
-	if (amend && in_merge)
-		die("You are in the middle of a merge -- cannot amend.");
+	if (amend && whence != FROM_COMMIT)
+		die("You are in the middle of a %s -- cannot amend.", whence_s());
 	if (fixup_message && squash_message)
 		die("Options --squash and --fixup cannot be used together");
 	if (use_message)
@@ -947,26 +1004,18 @@ static int parse_and_validate_options(int argc, const char *argv[],
 		use_message = edit_message;
 	if (amend && !use_message && !fixup_message)
 		use_message = "HEAD";
-	if (!use_message && renew_authorship)
+	if (!use_message && whence != FROM_CHERRY_PICK && renew_authorship)
 		die("--reset-author can be used only with -C, -c or --amend.");
 	if (use_message) {
-		const char *out_enc;
-		struct commit *commit;
-
-		commit = lookup_commit_reference_by_name(use_message);
-		if (!commit)
-			die("could not lookup commit %s", use_message);
-		out_enc = get_commit_output_encoding();
-		use_message_buffer = logmsg_reencode(commit, out_enc);
-
-		/*
-		 * If we failed to reencode the buffer, just copy it
-		 * byte for byte so the user can try to fix it up.
-		 * This also handles the case where input and output
-		 * encodings are identical.
-		 */
-		if (use_message_buffer == NULL)
-			use_message_buffer = xstrdup(commit->buffer);
+		use_message_buffer = read_commit_message(use_message);
+		if (!renew_authorship) {
+			author_message = use_message;
+			author_message_buffer = use_message_buffer;
+		}
+	}
+	if (whence == FROM_CHERRY_PICK && !renew_authorship) {
+		author_message = cherry_pick_head;
+		author_message_buffer = read_commit_message(author_message);
 	}
 
 	if (!!also + !!only + !!all + !!interactive > 1)
@@ -1117,7 +1166,7 @@ int cmd_status(int argc, const char **argv, const char *prefix)
 	wt_status_prepare(&s);
 	gitmodules_config();
 	git_config(git_status_config, &s);
-	in_merge = file_exists(git_path("MERGE_HEAD"));
+	determine_whence(&s);
 	argc = parse_options(argc, argv, prefix,
 			     builtin_status_options,
 			     builtin_status_usage, 0);
@@ -1140,7 +1189,6 @@ int cmd_status(int argc, const char **argv, const char *prefix)
 	}
 
 	s.is_initial = get_sha1(s.reference, sha1) ? 1 : 0;
-	s.in_merge = in_merge;
 	s.ignore_submodule_arg = ignore_submodule_arg;
 	wt_status_collect(&s);
 
@@ -1302,8 +1350,7 @@ int cmd_commit(int argc, const char **argv, const char *prefix)
 
 	wt_status_prepare(&s);
 	git_config(git_commit_config, &s);
-	in_merge = file_exists(git_path("MERGE_HEAD"));
-	s.in_merge = in_merge;
+	determine_whence(&s);
 
 	if (s.use_color == -1)
 		s.use_color = git_use_color_default;
@@ -1340,17 +1387,17 @@ int cmd_commit(int argc, const char **argv, const char *prefix)
 
 		for (c = commit->parents; c; c = c->next)
 			pptr = &commit_list_insert(c->item, pptr)->next;
-	} else if (in_merge) {
+	} else if (whence == FROM_MERGE) {
 		struct strbuf m = STRBUF_INIT;
 		FILE *fp;
 
 		if (!reflog_msg)
 			reflog_msg = "commit (merge)";
 		pptr = &commit_list_insert(lookup_commit(head_sha1), pptr)->next;
-		fp = fopen(git_path("MERGE_HEAD"), "r");
+		fp = fopen(git_path(merge_head), "r");
 		if (fp == NULL)
 			die_errno("could not open '%s' for reading",
-				  git_path("MERGE_HEAD"));
+				  git_path(merge_head));
 		while (strbuf_getline(&m, fp, '\n') != EOF) {
 			unsigned char sha1[20];
 			if (get_sha1_hex(m.buf, sha1) < 0)
@@ -1369,7 +1416,9 @@ int cmd_commit(int argc, const char **argv, const char *prefix)
 			parents = reduce_heads(parents);
 	} else {
 		if (!reflog_msg)
-			reflog_msg = "commit";
+			reflog_msg = (whence == FROM_CHERRY_PICK)
+					? "commit (cherry-pick)"
+					: "commit";
 		pptr = &commit_list_insert(lookup_commit(head_sha1), pptr)->next;
 	}
 
@@ -1424,8 +1473,8 @@ int cmd_commit(int argc, const char **argv, const char *prefix)
 		die("cannot update HEAD ref");
 	}
 
-	unlink(git_path("CHERRY_PICK_HEAD"));
-	unlink(git_path("MERGE_HEAD"));
+	unlink(git_path(cherry_pick_head));
+	unlink(git_path(merge_head));
 	unlink(git_path("MERGE_MSG"));
 	unlink(git_path("MERGE_MODE"));
 	unlink(git_path("SQUASH_MSG"));
diff --git a/builtin/revert.c b/builtin/revert.c
index cced2e4..28d1d70 100644
--- a/builtin/revert.c
+++ b/builtin/revert.c
@@ -3,7 +3,6 @@
 #include "object.h"
 #include "commit.h"
 #include "tag.h"
-#include "wt-status.h"
 #include "run-command.h"
 #include "exec_cmd.h"
 #include "utf8.h"
@@ -198,56 +197,6 @@ static void add_message_to_msg(struct strbuf *msgbuf, const char *message)
 	strbuf_addstr(msgbuf, p);
 }
 
-static void set_author_ident_env(const char *message)
-{
-	const char *p = message;
-	if (!p)
-		die ("Could not read commit message of %s",
-				sha1_to_hex(commit->object.sha1));
-	while (*p && *p != '\n') {
-		const char *eol;
-
-		for (eol = p; *eol && *eol != '\n'; eol++)
-			; /* do nothing */
-		if (!prefixcmp(p, "author ")) {
-			char *line, *pend, *email, *timestamp;
-
-			p += 7;
-			line = xmemdupz(p, eol - p);
-			email = strchr(line, '<');
-			if (!email)
-				die ("Could not extract author email from %s",
-					sha1_to_hex(commit->object.sha1));
-			if (email == line)
-				pend = line;
-			else
-				for (pend = email; pend != line + 1 &&
-						isspace(pend[-1]); pend--);
-					; /* do nothing */
-			*pend = '\0';
-			email++;
-			timestamp = strchr(email, '>');
-			if (!timestamp)
-				die ("Could not extract author time from %s",
-					sha1_to_hex(commit->object.sha1));
-			*timestamp = '\0';
-			for (timestamp++; *timestamp && isspace(*timestamp);
-					timestamp++)
-				; /* do nothing */
-			setenv("GIT_AUTHOR_NAME", line, 1);
-			setenv("GIT_AUTHOR_EMAIL", email, 1);
-			setenv("GIT_AUTHOR_DATE", timestamp, 1);
-			free(line);
-			return;
-		}
-		p = eol;
-		if (*p == '\n')
-			p++;
-	}
-	die ("No author information found in %s",
-			sha1_to_hex(commit->object.sha1));
-}
-
 static void write_cherry_pick_head(void)
 {
 	int fd;
@@ -284,9 +233,7 @@ static void print_advice(void)
 
 	advise("after resolving the conflicts, mark the corrected paths");
 	advise("with 'git add <paths>' or 'git rm <paths>'");
-
-	if (action == CHERRY_PICK)
-		advise("and commit the result with 'git commit -c CHERRY_PICK_HEAD'");
+	advise("and commit the result with 'git commit'");
 }
 
 static void write_message(struct strbuf *msgbuf, const char *filename)
@@ -512,7 +459,6 @@ static int do_pick_commit(void)
 		base_label = msg.parent_label;
 		next = commit;
 		next_label = msg.label;
-		set_author_ident_env(msg.message);
 		add_message_to_msg(&msgbuf, msg.message);
 		if (no_replay) {
 			strbuf_addstr(&msgbuf, "(cherry picked from commit ");
diff --git a/contrib/completion/git-completion.bash b/contrib/completion/git-completion.bash
index 893b771..0b0b913 100755
--- a/contrib/completion/git-completion.bash
+++ b/contrib/completion/git-completion.bash
@@ -246,6 +246,8 @@ __git_ps1 ()
 				fi
 			elif [ -f "$g/MERGE_HEAD" ]; then
 				r="|MERGING"
+			elif [ -f "$g/CHERRY_PICK_HEAD" ]; then
+				r="|CHERRY-PICKING"
 			elif [ -f "$g/BISECT_LOG" ]; then
 				r="|BISECTING"
 			fi
diff --git a/t/t3507-cherry-pick-conflict.sh b/t/t3507-cherry-pick-conflict.sh
index fd569c8..365a1ba 100755
--- a/t/t3507-cherry-pick-conflict.sh
+++ b/t/t3507-cherry-pick-conflict.sh
@@ -57,7 +57,7 @@ test_expect_success 'advice from failed cherry-pick' "
 	error: could not apply \$picked... picked
 	hint: after resolving the conflicts, mark the corrected paths
 	hint: with 'git add <paths>' or 'git rm <paths>'
-	hint: and commit the result with 'git commit -c CHERRY_PICK_HEAD'
+	hint: and commit the result with 'git commit'
 	EOF
 	test_must_fail git cherry-pick picked 2>actual &&
 
diff --git a/t/t7509-commit.sh b/t/t7509-commit.sh
index 77b6920..b61fd3c 100755
--- a/t/t7509-commit.sh
+++ b/t/t7509-commit.sh
@@ -157,4 +157,33 @@ test_expect_success '--reset-author should be rejected without -c/-C/--amend' '
 	test_must_fail git commit -a --reset-author -m done
 '
 
+test_expect_success 'commit respects CHERRY_PICK_HEAD and MERGE_MSG' '
+	echo "cherry-pick 1a" >>foo &&
+	test_tick &&
+	git commit -am "cherry-pick 1" --author="Cherry <cherry@pick.er>" &&
+	git tag cherry-pick-head &&
+	git rev-parse cherry-pick-head >.git/CHERRY_PICK_HEAD &&
+	echo "This is a MERGE_MSG" >.git/MERGE_MSG &&
+	echo "cherry-pick 1b" >>foo &&
+	test_tick &&
+	git commit -a &&
+	author_header cherry-pick-head >expect &&
+	author_header HEAD >actual &&
+	test_cmp expect actual &&
+
+	echo "This is a MERGE_MSG" >expect &&
+	message_body HEAD >actual &&
+	test_cmp expect actual
+'
+
+test_expect_success '--reset-author with CHERRY_PICK_HEAD' '
+	git rev-parse cherry-pick-head >.git/CHERRY_PICK_HEAD &&
+	echo "cherry-pick 2" >>foo &&
+	test_tick &&
+	git commit -am "cherry-pick 2" --reset-author &&
+	echo "author $GIT_AUTHOR_NAME <$GIT_AUTHOR_EMAIL> $GIT_AUTHOR_DATE" >expect &&
+	author_header HEAD >actual &&
+	test_cmp expect actual
+'
+
 test_done
diff --git a/wt-status.c b/wt-status.c
index 123582b..fbaaf54 100644
--- a/wt-status.c
+++ b/wt-status.c
@@ -60,7 +60,7 @@ static void wt_status_print_unmerged_header(struct wt_status *s)
 	color_fprintf_ln(s->fp, c, "# Unmerged paths:");
 	if (!advice_status_hints)
 		return;
-	if (s->in_merge)
+	if (s->whence != FROM_COMMIT)
 		;
 	else if (!s->is_initial)
 		color_fprintf_ln(s->fp, c, "#   (use \"git reset %s <file>...\" to unstage)", s->reference);
@@ -77,7 +77,7 @@ static void wt_status_print_cached_header(struct wt_status *s)
 	color_fprintf_ln(s->fp, c, "# Changes to be committed:");
 	if (!advice_status_hints)
 		return;
-	if (s->in_merge)
+	if (s->whence != FROM_COMMIT)
 		; /* NEEDSWORK: use "git reset --unresolve"??? */
 	else if (!s->is_initial)
 		color_fprintf_ln(s->fp, c, "#   (use \"git reset %s <file>...\" to unstage)", s->reference);
diff --git a/wt-status.h b/wt-status.h
index 20b17cf..bf2eb27 100644
--- a/wt-status.h
+++ b/wt-status.h
@@ -24,6 +24,12 @@ enum untracked_status_type {
 	SHOW_ALL_UNTRACKED_FILES
 };
 
+enum commit_whence {
+  FROM_COMMIT,
+  FROM_MERGE,
+  FROM_CHERRY_PICK
+};
+
 struct wt_status_change_data {
 	int worktree_status;
 	int index_status;
@@ -40,7 +46,7 @@ struct wt_status {
 	const char **pathspec;
 	int verbose;
 	int amend;
-	int in_merge;
+	enum commit_whence whence;
 	int nowarn;
 	int use_color;
 	int relative_paths;
-- 
1.7.4.1.28.gd46b3

Re: [PATCH 1/2] Introduce CHERRY_PICK_HEAD

[Nguyen Thai Ngoc Duy]

On Wed, Feb 16, 2011 at 5:08 PM, Jay Soffian <jaysoffian@gmail.com> wrote:
> When a cherry-pick conflicts git advises to use:
>
>  $ git commit -c <original commit id>
>
> to preserve the original commit message and authorship. Instead, let's
> record the original commit id in CHERRY_PICK_HEAD and advise to use:
>
>  $ git commit -c CHERRY_PICK_HEAD

Wouldn't it be more convenient to do "git cherry-pick --continue"
instead of "git commit -c CHERRY_PICK_HEAD"?
-- 
Duy

Re: [PATCH 1/2] Introduce CHERRY_PICK_HEAD

[Jay Soffian]

On Wed, Feb 16, 2011 at 6:13 AM, Nguyen Thai Ngoc Duy <pclouds@gmail.com> wrote:
> On Wed, Feb 16, 2011 at 5:08 PM, Jay Soffian <jaysoffian@gmail.com> wrote:
>> When a cherry-pick conflicts git advises to use:
>>
>>  $ git commit -c <original commit id>
>>
>> to preserve the original commit message and authorship. Instead, let's
>> record the original commit id in CHERRY_PICK_HEAD and advise to use:
>>
>>  $ git commit -c CHERRY_PICK_HEAD
>
> Wouldn't it be more convenient to do "git cherry-pick --continue"
> instead of "git commit -c CHERRY_PICK_HEAD"?

As mentioned in the part of the commit message you trimmed away: "In
the next commit, we teach git to handle the '-c CHERRY_PICK_HEAD'
part". Now, you may ask, why use "git commit" after resolving the
conflict (a la merge) instead of "git cherry-pick --continue" (a la
rebase).

I addressed this in the previous thread, see
http://article.gmane.org/gmane.comp.version-control.git/166884

j.

[PATCH v2] Introduce CHERRY_PICK_HEAD

[Jay Soffian]

When a cherry-pick conflicts git advises to use:

 $ git commit -c <original commit id>

to preserve the original commit message and authorship. Instead, let's
record the original commit id in CHERRY_PICK_HEAD and advise to use:

  $ git commit -c CHERRY_PICK_HEAD

In the next commit, we teach git to handle the '-c CHERRY_PICK_HEAD'
part. Note that we record CHERRY_PICK_HEAD even in the case where there
are no conflicts so that we may use it to communicate authorship to
commit; this will then allow us to remove set_author_ident_env from
revert.c.

Contributions-by: Jonathan Nieder <jrnieder@gmail.com>
Signed-off-by: Jay Soffian <jaysoffian@gmail.com>
---
Compared to the original patch, this removes CHERRY_PICK_HEAD when
a conflict occurs during an interactive rebase. Also corrected a minor
typo in the commit message. There were no changes to the next patch
in the series, so I didn't resend it.

 Documentation/git-cherry-pick.txt |   19 +++++++++++++++++++
 Documentation/revisions.txt       |    5 ++++-
 branch.c                          |    1 +
 builtin/commit.c                  |    1 +
 builtin/merge.c                   |    7 +++++++
 builtin/revert.c                  |   25 +++++++++++++++++++++++--
 t/t3507-cherry-pick-conflict.sh   |   22 +++++++++++++++++++++-
 7 files changed, 76 insertions(+), 4 deletions(-)

diff --git a/Documentation/git-cherry-pick.txt b/Documentation/git-cherry-pick.txt
index 749d68a..5d85daa 100644
--- a/Documentation/git-cherry-pick.txt
+++ b/Documentation/git-cherry-pick.txt
@@ -16,6 +16,25 @@ Given one or more existing commits, apply the change each one
 introduces, recording a new commit for each.  This requires your
 working tree to be clean (no modifications from the HEAD commit).
 
+When it is not obvious how to apply a change, the following
+happens:
+
+1. The current branch and `HEAD` pointer stay at the last commit
+   successfully made.
+2. The `CHERRY_PICK_HEAD` ref is set to point at the commit that
+   introduced the change that is difficult to apply.
+3. Paths in which the change applied cleanly are updated both
+   in the index file and in your working tree.
+4. For conflicting paths, the index file records up to three
+   versions, as described in the "TRUE MERGE" section of
+   linkgit:git-merge[1].  The working tree files will include
+   a description of the conflict bracketed by the usual
+   conflict markers `<<<<<<<` and `>>>>>>>`.
+5. No other modifications are made.
+
+See linkgit:git-merge[1] for some hints on resolving such
+conflicts.
+
 OPTIONS
 -------
 <commit>...::
diff --git a/Documentation/revisions.txt b/Documentation/revisions.txt
index 9e92734..04fceee 100644
--- a/Documentation/revisions.txt
+++ b/Documentation/revisions.txt
@@ -25,7 +25,8 @@ blobs contained in a commit.
   first match in the following rules:
 
   . if `$GIT_DIR/<name>` exists, that is what you mean (this is usually
-    useful only for `HEAD`, `FETCH_HEAD`, `ORIG_HEAD` and `MERGE_HEAD`);
+    useful only for `HEAD`, `FETCH_HEAD`, `ORIG_HEAD`, `MERGE_HEAD`
+    and `CHERRY_PICK_HEAD`);
 
   . otherwise, `refs/<name>` if exists;
 
@@ -46,6 +47,8 @@ you can change the tip of the branch back to the state before you ran
 them easily.
 MERGE_HEAD records the commit(s) you are merging into your branch
 when you run 'git merge'.
+CHERRY_PICK_HEAD records the commit you are cherry-picking
+when you run 'git cherry-pick'.
 +
 Note that any of the `refs/*` cases above may come either from
 the `$GIT_DIR/refs` directory or from the `$GIT_DIR/packed-refs` file.
diff --git a/branch.c b/branch.c
index 93dc866..dc23e95 100644
--- a/branch.c
+++ b/branch.c
@@ -217,6 +217,7 @@ void create_branch(const char *head,
 
 void remove_branch_state(void)
 {
+	unlink(git_path("CHERRY_PICK_HEAD"));
 	unlink(git_path("MERGE_HEAD"));
 	unlink(git_path("MERGE_RR"));
 	unlink(git_path("MERGE_MSG"));
diff --git a/builtin/commit.c b/builtin/commit.c
index 03cff5a..0def540 100644
--- a/builtin/commit.c
+++ b/builtin/commit.c
@@ -1424,6 +1424,7 @@ int cmd_commit(int argc, const char **argv, const char *prefix)
 		die("cannot update HEAD ref");
 	}
 
+	unlink(git_path("CHERRY_PICK_HEAD"));
 	unlink(git_path("MERGE_HEAD"));
 	unlink(git_path("MERGE_MSG"));
 	unlink(git_path("MERGE_MODE"));
diff --git a/builtin/merge.c b/builtin/merge.c
index 9403747..454dad2 100644
--- a/builtin/merge.c
+++ b/builtin/merge.c
@@ -971,6 +971,13 @@ int cmd_merge(int argc, const char **argv, const char *prefix)
 		else
 			die("You have not concluded your merge (MERGE_HEAD exists).");
 	}
+	if (file_exists(git_path("CHERRY_PICK_HEAD"))) {
+		if (advice_resolve_conflict)
+			die("You have not concluded your cherry-pick (CHERRY_PICK_HEAD exists).\n"
+			    "Please, commit your changes before you can merge.");
+		else
+			die("You have not concluded your cherry-pick (CHERRY_PICK_HEAD exists).");
+	}
 	resolve_undo_clear();
 
 	if (verbosity < 0)
diff --git a/builtin/revert.c b/builtin/revert.c
index dc1b702..88e3b2a 100644
--- a/builtin/revert.c
+++ b/builtin/revert.c
@@ -248,6 +248,22 @@ static void set_author_ident_env(const char *message)
 			sha1_to_hex(commit->object.sha1));
 }
 
+static void write_cherry_pick_head(void)
+{
+	int fd;
+	struct strbuf buf = STRBUF_INIT;
+
+	strbuf_addf(&buf, "%s\n", sha1_to_hex(commit->object.sha1));
+
+	fd = open(git_path("CHERRY_PICK_HEAD"), O_WRONLY | O_CREAT, 0666);
+	if (fd < 0)
+		die_errno("Could not open '%s' for writing",
+			  git_path("CHERRY_PICK_HEAD"));
+	if (write_in_full(fd, buf.buf, buf.len) != buf.len || close(fd))
+		die_errno("Could not write to '%s'", git_path("CHERRY_PICK_HEAD"));
+	strbuf_release(&buf);
+}
+
 static void advise(const char *advice, ...)
 {
 	va_list params;
@@ -263,6 +279,11 @@ static void print_advice(void)
 
 	if (msg) {
 		fprintf(stderr, "%s\n", msg);
+		/*
+		 * rebase interactive takes care of the authorship
+		 * when the user invokes rebase --continue
+		 */
+		unlink(git_path("CHERRY_PICK_HEAD"));
 		return;
 	}
 
@@ -270,8 +291,7 @@ static void print_advice(void)
 	advise("with 'git add <paths>' or 'git rm <paths>'");
 
 	if (action == CHERRY_PICK)
-		advise("and commit the result with 'git commit -c %s'",
-		       find_unique_abbrev(commit->object.sha1, DEFAULT_ABBREV));
+		advise("and commit the result with 'git commit -c CHERRY_PICK_HEAD'");
 }
 
 static void write_message(struct strbuf *msgbuf, const char *filename)
@@ -504,6 +524,7 @@ static int do_pick_commit(void)
 			strbuf_addstr(&msgbuf, sha1_to_hex(commit->object.sha1));
 			strbuf_addstr(&msgbuf, ")\n");
 		}
+		write_cherry_pick_head();
 	}
 
 	if (!strategy || !strcmp(strategy, "recursive") || action == REVERT) {
diff --git a/t/t3507-cherry-pick-conflict.sh b/t/t3507-cherry-pick-conflict.sh
index 607bf25..fd569c8 100755
--- a/t/t3507-cherry-pick-conflict.sh
+++ b/t/t3507-cherry-pick-conflict.sh
@@ -11,6 +11,12 @@ test_description='test cherry-pick and revert with conflicts
 
 . ./test-lib.sh
 
+test_cmp_rev () {
+	git rev-parse --verify "$1" >expect.rev &&
+	git rev-parse --verify "$2" >actual.rev &&
+	test_cmp expect.rev actual.rev
+}
+
 test_expect_success setup '
 
 	echo unrelated >unrelated &&
@@ -51,13 +57,27 @@ test_expect_success 'advice from failed cherry-pick' "
 	error: could not apply \$picked... picked
 	hint: after resolving the conflicts, mark the corrected paths
 	hint: with 'git add <paths>' or 'git rm <paths>'
-	hint: and commit the result with 'git commit -c \$picked'
+	hint: and commit the result with 'git commit -c CHERRY_PICK_HEAD'
 	EOF
 	test_must_fail git cherry-pick picked 2>actual &&
 
 	test_cmp expected actual
 "
 
+test_expect_success 'failed cherry-pick sets CHERRY_PICK_HEAD' '
+
+	git checkout -f initial^0 &&
+	git read-tree -u --reset HEAD &&
+	git clean -d -f -f -q -x &&
+
+	git update-index --refresh &&
+	git diff-index --exit-code HEAD &&
+
+	test_must_fail git cherry-pick picked &&
+
+	test_cmp_rev picked CHERRY_PICK_HEAD
+'
+
 test_expect_success 'failed cherry-pick produces dirty index' '
 
 	git checkout -f initial^0 &&
-- 
1.7.4.1.28.gb39462

Re: [PATCH v2] Introduce CHERRY_PICK_HEAD

[Jay Soffian]

On Wed, Feb 16, 2011 at 12:20 PM, Jay Soffian <jaysoffian@gmail.com> wrote:
> @@ -263,6 +279,11 @@ static void print_advice(void)
>
>        if (msg) {
>                fprintf(stderr, "%s\n", msg);
> +               /*
> +                * rebase interactive takes care of the authorship
> +                * when the user invokes rebase --continue
> +                */
> +               unlink(git_path("CHERRY_PICK_HEAD"));
>                return;
>        }
>
>

Oops, I amended the comment and then fed the wrong commit to
format-patch. That should be:

@@ -263,6 +279,11 @@ static void print_advice(void)

        if (msg) {
                fprintf(stderr, "%s\n", msg);
+               /*
+                * we're in the middle of an interactive rebase, we
+                * don't want it to look like we're cherry-picking.
+                */
+               unlink(git_path("CHERRY_PICK_HEAD"));
                return;
        }

Let me know if you want me to resend. (Sorry.)

j.

Re: [PATCH 2/2] Teach commit about CHERRY_PICK_HEAD

[Junio C Hamano]

Jay Soffian <jaysoffian@gmail.com> writes:

> If the user wishes to reset authorship, that must now be done explicitly
> via --reset-author.

This is not a new requirement, is it?  Even "commit -c $that_commit"
before the previous "commit -c CHERRY_PICK_HEAD" does use the original,
no?


I think the changed code is _MUCH_ easier to follow compared to the
previous round; the only thing the reader needs to keep in mind is that
the most of the change essentially is "s/in_merge/whence != FROM_COMMIT/"
and making that work.

> * We remove a unused import from revert.c

Micronit: s/import/include/.


> @@ -766,7 +802,7 @@ static int prepare_to_commit(const char *index_file, const char *prefix,
>  
>  	fclose(fp);
>  
> -	if (!commitable && !in_merge && !allow_empty &&
> +	if (!commitable && whence != FROM_MERGE && !allow_empty &&
>  	    !(amend && is_a_merge(head_sha1))) {
>  		run_status(stdout, index_file, prefix, 0, s);
>  		if (amend)

The original says that we reject an attempt to record a no-change commit
when the user is making his own commit without an explicit --allow-empty
request.  Should cherry-pick change this?

"git cherry-pick $a_no_change_commit" does not cause conflicts but it does
fail with "nothing added to commit".  If you said "whence == FROM_COMMIT"
here, you would end up allowing "git commit" following such a failure to
commit without --allow-empty, and that inconsistency is to be avoided
(note that I didn't check if you leave CHERRY_PICK_HEAD behind to trigger
this codepath when this happens).

On the other hand, when the earlier cherry-pick did fail with conflict,
but the resolution ended up to be a no-change commit, you would not
blindly want to record the result as a no-change commit, either.

So I think the above is the right thing to do, but we probably need a bit
of in-code comment to describe why we say "whence != FROM_MERGE" here.

Thanks.

Re: [PATCH 2/2] Teach commit about CHERRY_PICK_HEAD

[Jay Soffian]

On Wed, Feb 16, 2011 at 4:07 PM, Junio C Hamano <gitster@pobox.com> wrote:
> Jay Soffian <jaysoffian@gmail.com> writes:
>
>> If the user wishes to reset authorship, that must now be done explicitly
>> via --reset-author.
>
> This is not a new requirement, is it?  Even "commit -c $that_commit"
> before the previous "commit -c CHERRY_PICK_HEAD" does use the original,
> no?

It is a new requirement for when the user does a bare "commit" _and_
CHERRY_PICK_HEAD exists.

Normally a bare "commit" creates new authorship, but when
CHERRY_PICK_HEAD exists, authorship is taken from CHERRY_PICK_HEAD
commit unless --reset-author is specified.

> I think the changed code is _MUCH_ easier to follow compared to the
> previous round; the only thing the reader needs to keep in mind is that
> the most of the change essentially is "s/in_merge/whence != FROM_COMMIT/"
> and making that work.

I think I was trying to be too clever in the previous round.

>> * We remove a unused import from revert.c
>
> Micronit: s/import/include/.

Okay.

> So I think the above is the right thing to do, but we probably need a bit
> of in-code comment to describe why we say "whence != FROM_MERGE" here.

Will do. It took me several tries to understand what that code block
was trying to do, so a comment will certainly help future readers.

Thanks,

j.

Re: [PATCH v2] Introduce CHERRY_PICK_HEAD

[Jonathan Nieder]

Jay Soffian wrote:

> When a cherry-pick conflicts git advises to use:
>
>  $ git commit -c <original commit id>
>
> to preserve the original commit message and authorship. Instead, let's
> record the original commit id in CHERRY_PICK_HEAD and advise to use:
>
>   $ git commit -c CHERRY_PICK_HEAD
>
> In the next commit, we teach git to handle the '-c CHERRY_PICK_HEAD'
> part. Note that we record CHERRY_PICK_HEAD even in the case where there
> are no conflicts so that we may use it to communicate authorship to
> commit; this will then allow us to remove set_author_ident_env from
> revert.c.

This "In the next commit" phrasing is dangerous, since a person can
build on top of your first commit at any time. :)  I would say:

	A later patch will teach "git commit" without -c to use
	CHERRY_PICK_HEAD to set the authorship automatically. Note
	that[...]

[...]
> +++ b/builtin/revert.c
> @@ -263,6 +279,11 @@ static void print_advice(void)
>  
>  	if (msg) {
>  		fprintf(stderr, "%s\n", msg);
> +		/*
> +		 * rebase interactive takes care of the authorship
> +		 * when the user invokes rebase --continue
> +		 */
> +		unlink(git_path("CHERRY_PICK_HEAD"));

Nit: GIT_CHERRY_PICK_HELP is not just for rebase --interactive but
for arbitrary porcelain that wants to take care of the commit itself
(see v1.5.4-rc0~106^2~1, revert/cherry-pick: Allow overriding the
help text by the calling Porcelain, 2007-11-28).

The conservative thing to do is indeed to remove CHERRY_PICK_HEAD in
this case, I suppose.  But I'd like to have the CHERRY_PICK_HEAD to
get the --amend safety when rebasing.  I can send a separate patch
for it if you'd like.

> --- a/t/t3507-cherry-pick-conflict.sh
> +++ b/t/t3507-cherry-pick-conflict.sh
> @@ -11,6 +11,12 @@ test_description='test cherry-pick and revert with conflicts
[...]
> +test_expect_success 'failed cherry-pick sets CHERRY_PICK_HEAD' '

Some more tests.  Yes, they are repetitive.  A patch on top to factor
out the setup into a function might help, but that feels out of scope
here.

With whatever subset of the below looks good,
Reviewed-by: Jonathan Nieder <jrnieder@gmail.com>

Thanks.
---
 t/t3507-cherry-pick-conflict.sh |  116 +++++++++++++++++++++++++++++++++++++++
 1 files changed, 116 insertions(+), 0 deletions(-)

diff --git a/t/t3507-cherry-pick-conflict.sh b/t/t3507-cherry-pick-conflict.sh
index fd569c8..ea52720 100755
--- a/t/t3507-cherry-pick-conflict.sh
+++ b/t/t3507-cherry-pick-conflict.sh
@@ -78,6 +78,122 @@ test_expect_success 'failed cherry-pick sets CHERRY_PICK_HEAD' '
 	test_cmp_rev picked CHERRY_PICK_HEAD
 '
 
+test_expect_success 'successful cherry-pick does not set CHERRY_PICK_HEAD' '
+
+	git checkout -f initial^0 &&
+	git read-tree -u --reset HEAD &&
+	git clean -d -f -f -q -x &&
+
+	git update-index --refresh &&
+	git diff-index --exit-code HEAD &&
+
+	git cherry-pick base &&
+
+	test_must_fail git rev-parse --verify CHERRY_PICK_HEAD
+'
+
+test_expect_success 'cherry-pick --no-commit sets CHERRY_PICK_HEAD' '
+
+	git checkout -f initial^0 &&
+	git read-tree -u --reset HEAD &&
+	git clean -d -f -f -q -x &&
+
+	git update-index --refresh &&
+	git diff-index --exit-code HEAD &&
+
+	git cherry-pick --no-commit base &&
+
+	test_cmp_rev base CHERRY_PICK_HEAD
+'
+
+test_expect_success 'GIT_CHERRY_PICK_HELP suppresses CHERRY_PICK_HEAD' '
+
+	git checkout -f initial^0 &&
+	git read-tree -u --reset HEAD &&
+	git clean -d -f -f -q -x &&
+
+	git update-index --refresh &&
+	git diff-index --exit-code HEAD &&
+
+	(
+		GIT_CHERRY_PICK_HELP="and then do something else" &&
+		export GIT_CHERRY_PICK_HELP &&
+		test_must_fail git cherry-pick picked
+	) &&
+
+	test_must_fail git rev-parse --verify CHERRY_PICK_HEAD
+'
+
+test_expect_success 'git reset clears CHERRY_PICK_HEAD' '
+
+	git checkout -f initial^0 &&
+	git read-tree -u --reset HEAD &&
+	git clean -d -f -f -q -x &&
+
+	git update-index --refresh &&
+	git diff-index --exit-code HEAD &&
+
+	test_must_fail git cherry-pick picked &&
+	git reset &&
+
+	test_must_fail git rev-parse --verify CHERRY_PICK_HEAD
+'
+
+test_expect_success 'failed commit does not clear CHERRY_PICK_HEAD' '
+
+	git checkout -f initial^0 &&
+	git read-tree -u --reset HEAD &&
+	git clean -d -f -f -q -x &&
+
+	git update-index --refresh &&
+	git diff-index --exit-code HEAD &&
+
+	test_must_fail git cherry-pick picked &&
+	test_must_fail git commit &&
+
+	test_cmp_rev picked CHERRY_PICK_HEAD
+'
+
+test_expect_success 'cancelled commit does not clear CHERRY_PICK_HEAD' '
+
+	git checkout -f initial^0 &&
+	git read-tree -u --reset HEAD &&
+	git clean -d -f -f -q -x &&
+
+	git update-index --refresh &&
+	git diff-index --exit-code HEAD &&
+
+	test_must_fail git cherry-pick picked &&
+	echo resolved >foo &&
+	git add foo &&
+	git update-index --refresh -q &&
+	test_must_fail git diff-index --exit-code HEAD &&
+	(
+		GIT_EDITOR=false &&
+		export GIT_EDITOR &&
+		test_must_fail git commit
+	) &&
+
+	test_cmp_rev picked CHERRY_PICK_HEAD
+'
+
+test_expect_success 'successful commit clears CHERRY_PICK_HEAD' '
+
+	git checkout -f initial^0 &&
+	git read-tree -u --reset HEAD &&
+	git clean -d -f -f -q -x &&
+
+	git update-index --refresh &&
+	git diff-index --exit-code HEAD &&
+
+	test_must_fail git cherry-pick picked &&
+	echo resolved >foo &&
+	git add foo &&
+	git commit &&
+
+	test_must_fail git rev-parse --verify CHERRY_PICK_HEAD
+'
+
 test_expect_success 'failed cherry-pick produces dirty index' '
 
 	git checkout -f initial^0 &&
-- 
1.7.4.1

[PATCH 1.5/2] bash: teach __git_ps1 about CHERRY_PICK_HEAD

[Jonathan Nieder]

From: Jay Soffian <jaysoffian@gmail.com>

Make the git prompt (when enabled) show a CHERRY-PICKING indicator
when we are in the middle of a conflicted cherry-pick, analogous
to the existing MERGING and BISECTING flags.

Signed-off-by: Jay Soffian <jaysoffian@gmail.com>
Signed-off-by: Jonathan Nieder <jrnieder@gmail.com>
---
> * While we're at it, we update git-completion.bash to be
>   CHERRY_PICK_HEAD aware.

Hmm, it seems I don't like this "while at it". :)

 contrib/completion/git-completion.bash |    2 ++
 1 files changed, 2 insertions(+), 0 deletions(-)

diff --git a/contrib/completion/git-completion.bash b/contrib/completion/git-completion.bash
index 893b771..0b0b913 100755
--- a/contrib/completion/git-completion.bash
+++ b/contrib/completion/git-completion.bash
@@ -246,6 +246,8 @@ __git_ps1 ()
 				fi
 			elif [ -f "$g/MERGE_HEAD" ]; then
 				r="|MERGING"
+			elif [ -f "$g/CHERRY_PICK_HEAD" ]; then
+				r="|CHERRY-PICKING"
 			elif [ -f "$g/BISECT_LOG" ]; then
 				r="|BISECTING"
 			fi
-- 
1.7.4.1

Re: [PATCH v2] Introduce CHERRY_PICK_HEAD

[Jay Soffian]

On Wed, Feb 16, 2011 at 4:42 PM, Jonathan Nieder <jrnieder@gmail.com> wrote:
> Nit: GIT_CHERRY_PICK_HELP is not just for rebase --interactive but
> for arbitrary porcelain that wants to take care of the commit itself
> (see v1.5.4-rc0~106^2~1, revert/cherry-pick: Allow overriding the
> help text by the calling Porcelain, 2007-11-28).

What is the arbitrary porcelain you have in mind? :-)

> The conservative thing to do is indeed to remove CHERRY_PICK_HEAD in
> this case, I suppose.  But I'd like to have the CHERRY_PICK_HEAD to
> get the --amend safety when rebasing.  I can send a separate patch
> for it if you'd like.

Please do, since I'm not really sure what you have in mind. If
CHERRY_PICK_HEAD is left-behind, it interferes with the eventually
commit done by rebase --continue. I suppose we could give commit.c
some additional logic to detect when it's being called by rebase
(setting whence = FROM_REBASE?).

In the mean time, I'll re-roll with your additional tests and Junio's
prior feedback.

Thanks,

j.

Re: [PATCH 2/2] Teach commit about CHERRY_PICK_HEAD

[Jonathan Nieder]

Jay Soffian wrote:

> This change fixes that situation. A bare 'commit' will now take the
> authorship from CHERRY_PICK_HEAD and the commit message from MERGE_MSG.
> If the user wishes to reset authorship, that must now be done explicitly
> via --reset-author.

Might also be worth mentioning that it makes --amend fail in such a
situation (a change worth celebrating).

> --- a/builtin/commit.c
> +++ b/builtin/commit.c
> @@ -56,8 +56,10 @@ static const char empty_amend_advice[] =
>  
>  static unsigned char head_sha1[20];
>  
> -static char *use_message_buffer;
> +static const char *use_message_buffer;
>  static const char commit_editmsg[] = "COMMIT_EDITMSG";
> +static const char cherry_pick_head[] = "CHERRY_PICK_HEAD";
> +static const char merge_head[] = "MERGE_HEAD";

Hmm, these variables but not MERGE_MSG, MERGE_MODE, and SQUASH_MSG?

> @@ -68,6 +70,7 @@ static enum {
>  
>  static const char *logfile, *force_author;
>  static const char *template_file;
> +static const char *author_message, *author_message_buffer;

That's not a message at all, is it?  On first reading I thought it
would be a message about the author.  Maybe a comment can help.

	/* name and content of commit from which to copy authorship */

> @@ -88,7 +91,8 @@ static enum {
>  } cleanup_mode;
>  static char *cleanup_arg;
>  
> -static int use_editor = 1, initial_commit, in_merge, include_status = 1;
> +static enum commit_whence whence;
> +static int use_editor = 1, initial_commit, include_status = 1;

The name "whence" is not so self-explanatory but I don't have any
better ideas (I probably would have written "merge_or_cherry_pick"; we
can be glad you came up with something better).

> @@ -163,6 +167,36 @@ static struct option builtin_commit_options[] = {
>  	OPT_END()
>  };
>  
> +static void determine_whence(struct wt_status *s)
> +{
> +	if (file_exists(git_path(merge_head)))
> +		whence = FROM_MERGE;

Micronit: maybe COMMITTING_A_MERGE or COMMIT_DURING_MERGE to avoid
using valuable namespace?

> @@ -644,7 +678,7 @@ static int prepare_to_commit(const char *index_file, const char *prefix,
>  	 * This final case does not modify the template message,
>  	 * it just sets the argument to the prepare-commit-msg hook.
>  	 */
> -	else if (in_merge)
> +	else if (whence == FROM_MERGE)
>  		hook_arg1 = "merge";

Perhaps:

	else if (whence == CHERRY_PICK) {
		hook_arg1 = "commit";
		hook_arg2 = author_message;
	}

> @@ -694,16 +728,18 @@ static int prepare_to_commit(const char *index_file, const char *prefix,
[...]
>  				"# If this is not correct, please remove the file\n"
>  				"#	%s\n"
>  				"# and try again.\n"
>  				"#\n",
> +				whence_s(),
> +				git_path(whence == FROM_MERGE
> +					 ? merge_head
> +					 : cherry_pick_head));

Ok.  We probably should move away from having to suggest
"rm -f .git/whatever" in the future (maybe

	git update-ref -d %s

is simpler advice?  I dunno).

> @@ -898,6 +934,27 @@ static void handle_untracked_files_arg(struct wt_status *s)
>  		die("Invalid untracked files mode '%s'", untracked_files_arg);
>  }
>  
> +static const char *read_commit_message(const char *name) {

Nice.  Opening '{' should be in the first column.

> +++ b/builtin/revert.c
[...]
> @@ -284,9 +233,7 @@ static void print_advice(void)
>  
>  	advise("after resolving the conflicts, mark the corrected paths");
>  	advise("with 'git add <paths>' or 'git rm <paths>'");
> -
> -	if (action == CHERRY_PICK)
> -		advise("and commit the result with 'git commit -c CHERRY_PICK_HEAD'");
> +	advise("and commit the result with 'git commit'");

Hoorah!

> --- a/wt-status.c
> +++ b/wt-status.c
> @@ -60,7 +60,7 @@ static void wt_status_print_unmerged_header(struct wt_status *s)
>  	color_fprintf_ln(s->fp, c, "# Unmerged paths:");
>  	if (!advice_status_hints)
>  		return;
> -	if (s->in_merge)
> +	if (s->whence != FROM_COMMIT)
>  		;
>  	else if (!s->is_initial)
>  		color_fprintf_ln(s->fp, c, "#   (use \"git reset %s <file>...\" to unstage)", s->reference);

Isn't the advice of using "git reset -- <paths>" still good in the
CHERRY_PICK case?

> @@ -77,7 +77,7 @@ static void wt_status_print_cached_header(struct wt_status *s)
>  	color_fprintf_ln(s->fp, c, "# Changes to be committed:");
>  	if (!advice_status_hints)
>  		return;
> -	if (s->in_merge)
> +	if (s->whence != FROM_COMMIT)
>  		; /* NEEDSWORK: use "git reset --unresolve"??? */

Likewise here.

> --- a/wt-status.h
> +++ b/wt-status.h
> @@ -24,6 +24,12 @@ enum untracked_status_type {
>  	SHOW_ALL_UNTRACKED_FILES
>  };
>  
> +enum commit_whence {
> +  FROM_COMMIT,
> +  FROM_MERGE,
> +  FROM_CHERRY_PICK
> +};

Style: please use tabs to indent.

> @@ -40,7 +46,7 @@ struct wt_status {
>  	const char **pathspec;
>  	int verbose;
>  	int amend;
> -	int in_merge;
> +	enum commit_whence whence;

Might benefit from a comment.

	/* whether a merge or cherry-pick is in progress */
	enum commit_whence whence;

Thanks, very readable.

Re: [PATCH 1.5/2] bash: teach __git_ps1 about CHERRY_PICK_HEAD

[Junio C Hamano]

Jonathan Nieder <jrnieder@gmail.com> writes:

> Hmm, it seems I don't like this "while at it". :)

I don't either.  The series will be re-rolled so I don't have to pick this
up myself, yes?

Re: [PATCH v2] Introduce CHERRY_PICK_HEAD

[Jonathan Nieder]

Jay Soffian wrote:
> On Wed, Feb 16, 2011 at 4:42 PM, Jonathan Nieder <jrnieder@gmail.com> wrote:

>> Nit: GIT_CHERRY_PICK_HELP is not just for rebase --interactive but
>> for arbitrary porcelain that wants to take care of the commit itself
>> (see v1.5.4-rc0~106^2~1, revert/cherry-pick: Allow overriding the
>> help text by the calling Porcelain, 2007-11-28).
>
> What is the arbitrary porcelain you have in mind? :-)

git sequencer, for example.  Or any out-of-tree tool that is using
cherry-pick to move around commits and wants to know where they end
up.

>> The conservative thing to do is indeed to remove CHERRY_PICK_HEAD in
>> this case, I suppose.  But I'd like to have the CHERRY_PICK_HEAD to
>> get the --amend safety when rebasing.  I can send a separate patch
>> for it if you'd like.
>
> Please do, since I'm not really sure what you have in mind. If
> CHERRY_PICK_HEAD is left-behind, it interferes with the eventually
> commit done by rebase --continue.

Wait, does this mean that -c/-C/--amend/CHERRY_PICK_HEAD overrides
GIT_AUTHOR_NAME, GIT_AUTHOR_EMAIL, and GIT_AUTHOR_DATE?

*checks*

Yes, it does.  The behavior is carried over from v0.99~185
(git-commit-script: get commit message from an existing one,
2005-06-25), but imho it is wrong.

Does this seem worth fixing?
Jonathan

Re: [PATCH 2/2] Teach commit about CHERRY_PICK_HEAD

[Jay Soffian]

On Wed, Feb 16, 2011 at 5:43 PM, Jonathan Nieder <jrnieder@gmail.com> wrote:
> Might also be worth mentioning that it makes --amend fail in such a
> situation (a change worth celebrating).

Never made that particular mistake myself, but okay.

>> --- a/builtin/commit.c
>> +++ b/builtin/commit.c
>> @@ -56,8 +56,10 @@ static const char empty_amend_advice[] =
>>
>>  static unsigned char head_sha1[20];
>>
>> -static char *use_message_buffer;
>> +static const char *use_message_buffer;
>>  static const char commit_editmsg[] = "COMMIT_EDITMSG";
>> +static const char cherry_pick_head[] = "CHERRY_PICK_HEAD";
>> +static const char merge_head[] = "MERGE_HEAD";
>
> Hmm, these variables but not MERGE_MSG, MERGE_MODE, and SQUASH_MSG?

I cleaned up the ones my patch touched. Cleaning up the rest of
commit.c was out of my purview. :-)

I'll clean them up to be consistent, but I'll do it as a separate
patch (before this one).

>> @@ -68,6 +70,7 @@ static enum {
>>
>>  static const char *logfile, *force_author;
>>  static const char *template_file;
>> +static const char *author_message, *author_message_buffer;
>
> That's not a message at all, is it?  On first reading I thought it
> would be a message about the author.  Maybe a comment can help.
>
>        /* name and content of commit from which to copy authorship */

The name is consistent with the other similar purpose variables:
use_message, edit_message, squash_message, fixup_message, which all
take a committish and aren't actually messages. None of those others
have comments, but it's obvious in context how they are used.

>> @@ -88,7 +91,8 @@ static enum {
>>  } cleanup_mode;
>>  static char *cleanup_arg;
>>
>> -static int use_editor = 1, initial_commit, in_merge, include_status = 1;
>> +static enum commit_whence whence;
>> +static int use_editor = 1, initial_commit, include_status = 1;
>
> The name "whence" is not so self-explanatory but I don't have any
> better ideas (I probably would have written "merge_or_cherry_pick"; we
> can be glad you came up with something better).

Respectfully disagree. Whence means "from where something came" as in
"from where did this commit we're about to make originate?" and I
intentionally didn't use _ORIGIN as "origin" has another meaning
already in git context.

>> @@ -163,6 +167,36 @@ static struct option builtin_commit_options[] = {
>>       OPT_END()
>>  };
>>
>> +static void determine_whence(struct wt_status *s)
>> +{
>> +     if (file_exists(git_path(merge_head)))
>> +             whence = FROM_MERGE;
>
> Micronit: maybe COMMITTING_A_MERGE or COMMIT_DURING_MERGE to avoid
> using valuable namespace?

Respectfully disagree.

> Perhaps:
>
>        else if (whence == CHERRY_PICK) {
>                hook_arg1 = "commit";
>                hook_arg2 = author_message;
>        }

Perhaps.

> Ok.  We probably should move away from having to suggest
> "rm -f .git/whatever" in the future (maybe
>
>        git update-ref -d %s
>
> is simpler advice?  I dunno).

Out of scope for this patch. :-)

> Nice.  Opening '{' should be in the first column.

Good catch.

> Isn't the advice of using "git reset -- <paths>" still good in the
> CHERRY_PICK case?

I don't know. I couldn't make up my mind. If it's a conflicted path
you've edited in the working copy, then the advice should be "checkout
--merge". I think. Maybe. I don't find wt-status.c to be very much
fun, so I punted.

>> -     if (s->in_merge)
>> +     if (s->whence != FROM_COMMIT)
>>               ; /* NEEDSWORK: use "git reset --unresolve"??? */
>
> Likewise here.

Checkout that NEEDSWORK. Someone should get on that. :-)

> Style: please use tabs to indent.

Who ate my tabs?

> Might benefit from a comment.
>
>        /* whether a merge or cherry-pick is in progress */
>        enum commit_whence whence;

Agreed.

> Thanks, very readable.

Good feedback.

j.

Re: [PATCH v2] Introduce CHERRY_PICK_HEAD

[Junio C Hamano]

Jonathan Nieder <jrnieder@gmail.com> writes:

> Wait, does this mean that -c/-C/--amend/CHERRY_PICK_HEAD overrides
> GIT_AUTHOR_NAME, GIT_AUTHOR_EMAIL, and GIT_AUTHOR_DATE?
>
> *checks*
>
> Yes, it does.  The behavior is carried over from v0.99~185
> (git-commit-script: get commit message from an existing one,
> 2005-06-25), but imho it is wrong.

Hmph, -c/-C/--amend is like giving the identity with --author from the
command line so overriding the values from the environment variables
sounds like the right thing to do.

Where am I confused?

Re: [PATCH v2] Introduce CHERRY_PICK_HEAD

[Jonathan Nieder]

Junio C Hamano wrote:
> Jonathan Nieder <jrnieder@gmail.com> writes:

>> Wait, does this mean that -c/-C/--amend/CHERRY_PICK_HEAD overrides
>> GIT_AUTHOR_NAME, GIT_AUTHOR_EMAIL, and GIT_AUTHOR_DATE?
[...]
> Hmph, -c/-C/--amend is like giving the identity with --author from the
> command line so overriding the values from the environment variables
> sounds like the right thing to do.

Good point.  There are two principles at work here:

 - options with more specific effect override more general ones
 - options on the command line override the environment

On second thought, the latter does seem more relevant (though it need
not apply to CHERRY_PICK_HEAD).

Thanks for a sanity check.
Jonathan