[PATCH 1/3] cherry-pick: add support to copy notes

[Felipe Contreras <felipe.contreras@gmail.com>]

Signed-off-by: Felipe Contreras <felipe.contreras@gmail.com>
---
 builtin/revert.c  |   2 +
 sequencer.c       | 136 ++++++++++++++++++++++++++++++++++++++++++++++++++++--
 sequencer.h       |   2 +
 t/t3500-cherry.sh |  32 +++++++++++++
 4 files changed, 169 insertions(+), 3 deletions(-)

diff --git a/builtin/revert.c b/builtin/revert.c
index 0e5ce71..b977124 100644
--- a/builtin/revert.c
+++ b/builtin/revert.c
@@ -119,6 +119,7 @@ static void parse_args(int argc, const char **argv, struct replay_opts *opts)
 		OPT_END(),
 		OPT_END(),
 		OPT_END(),
+		OPT_END(),
 	};
 
 	if (opts->action == REPLAY_PICK) {
@@ -129,6 +130,7 @@ static void parse_args(int argc, const char **argv, struct replay_opts *opts)
 			OPT_BOOLEAN(0, "allow-empty-message", &opts->allow_empty_message, N_("allow commits with empty messages")),
 			OPT_BOOLEAN(0, "keep-redundant-commits", &opts->keep_redundant_commits, N_("keep redundant, empty commits")),
 			OPT_BOOLEAN(0, "skip-empty", &opts->skip_empty, N_("skip empty commits")),
+			OPT_BOOLEAN(0, "copy-notes", &opts->copy_notes, N_("copy notes")),
 			OPT_END(),
 		};
 		if (parse_options_concat(options, ARRAY_SIZE(options), cp_extra))
diff --git a/sequencer.c b/sequencer.c
index edf141d..35a84ad 100644
--- a/sequencer.c
+++ b/sequencer.c
@@ -20,6 +20,18 @@
 const char sign_off_header[] = "Signed-off-by: ";
 static const char cherry_picked_prefix[] = "(cherry picked from commit ";
 
+struct rewritten_list_item {
+	unsigned char from[20];
+	unsigned char to[20];
+};
+
+struct rewritten_list {
+	struct rewritten_list_item *items;
+	unsigned int nr, alloc;
+};
+
+static struct rewritten_list rewritten;
+
 static int is_rfc2822_line(const char *buf, int len)
 {
 	int i;
@@ -102,6 +114,40 @@ static int has_conforming_footer(struct strbuf *sb, struct strbuf *sob,
 	return 1;
 }
 
+static void add_rewritten(unsigned char *from, unsigned char *to)
+{
+	struct rewritten_list_item *item;
+	if (rewritten.nr + 1 >= rewritten.alloc) {
+		rewritten.alloc += 32;
+		rewritten.items = xrealloc(rewritten.items, rewritten.alloc * sizeof(*rewritten.items));
+	}
+	item = &rewritten.items[rewritten.nr];
+	hashcpy(item->from, from);
+	hashcpy(item->to, to);
+	rewritten.nr++;
+}
+
+static void copy_notes(void)
+{
+	unsigned char note_commit[20];
+	struct strbuf buf = STRBUF_INIT;
+	struct notes_tree *t = &default_notes_tree;
+	int i;
+
+	init_notes(t, NULL, NULL, 0);
+
+	for (i = 0; i < rewritten.nr; i++) {
+		struct rewritten_list_item *item = &rewritten.items[i];
+		copy_note(t, item->from, item->to, 0, NULL);
+	}
+
+	strbuf_addstr(&buf, "Notes added by 'git cherry-pick'\n");
+	create_notes_commit(&default_notes_tree, NULL, &buf, note_commit);
+	strbuf_insert(&buf, 0, "notes: ", 7);
+	update_ref(buf.buf, t->ref, note_commit, NULL, 0, MSG_ON_ERR);
+	strbuf_release(&buf);
+}
+
 static void remove_sequencer_state(void)
 {
 	struct strbuf seq_dir = STRBUF_INIT;
@@ -641,6 +687,14 @@ static int do_pick_commit(struct commit *commit, struct replay_opts *opts)
 			res = run_git_commit(defmsg, opts, allow);
 	}
 
+	if (!res && opts->copy_notes) {
+		unsigned char to[20];
+
+		if (read_ref("HEAD", to))
+			goto leave;
+
+		add_rewritten(commit->object.sha1, to);
+	}
 leave:
 	free_message(&msg);
 	free(defmsg);
@@ -786,6 +840,40 @@ static void read_populate_todo(struct commit_list **todo_list,
 		die(_("Unusable instruction sheet: %s"), todo_file);
 }
 
+static void read_populate_rewritten(void)
+{
+	const char *rewritten_file = git_path(SEQ_REWR_FILE);
+	struct strbuf buf = STRBUF_INIT;
+	char *p;
+	int fd;
+
+	fd = open(rewritten_file, O_RDONLY);
+	if (fd < 0)
+		return;
+	if (strbuf_read(&buf, fd, 0) < 0) {
+		close(fd);
+		strbuf_release(&buf);
+		return;
+	}
+	close(fd);
+
+	for (p = buf.buf; *p;) {
+		unsigned char from[20];
+		unsigned char to[20];
+		char *eol = strchrnul(p, '\n');
+		if (eol - p != 81)
+			/* wrong size */
+			break;
+		if (get_sha1_hex(p, from))
+			break;
+		if (get_sha1_hex(p + 41, to))
+			break;
+		add_rewritten(from, to);
+		p = *eol ? eol + 1 : eol;
+	}
+	strbuf_release(&buf);
+}
+
 static int populate_opts_cb(const char *key, const char *value, void *data)
 {
 	struct replay_opts *opts = data;
@@ -810,7 +898,10 @@ static int populate_opts_cb(const char *key, const char *value, void *data)
 	else if (!strcmp(key, "options.strategy-option")) {
 		ALLOC_GROW(opts->xopts, opts->xopts_nr + 1, opts->xopts_alloc);
 		opts->xopts[opts->xopts_nr++] = xstrdup(value);
-	} else
+	}
+	else if (!strcmp(key, "options.copy-notes"))
+		opts->copy_notes = git_config_bool_or_int(key, value, &error_flag);
+	else
 		return error(_("Invalid key: %s"), key);
 
 	if (!error_flag)
@@ -958,6 +1049,29 @@ static void save_todo(struct commit_list *todo_list, struct replay_opts *opts)
 	strbuf_release(&buf);
 }
 
+static void save_rewritten(void)
+{
+	const char *todo_file = git_path(SEQ_REWR_FILE);
+	static struct lock_file rewritten_lock;
+	struct strbuf buf = STRBUF_INIT;
+	int fd, i;
+
+	fd = hold_lock_file_for_update(&rewritten_lock, todo_file, LOCK_DIE_ON_ERROR);
+	for (i = 0; i < rewritten.nr; i++) {
+		struct rewritten_list_item *item = &rewritten.items[i];
+		strbuf_addf(&buf, "%s %s\n", sha1_to_hex(item->from), sha1_to_hex(item->to));
+	}
+	if (write_in_full(fd, buf.buf, buf.len) < 0) {
+		strbuf_release(&buf);
+		die_errno(_("Could not write to %s"), todo_file);
+	}
+	if (commit_lock_file(&rewritten_lock) < 0) {
+		strbuf_release(&buf);
+		die(_("Error wrapping up %s."), todo_file);
+	}
+	strbuf_release(&buf);
+}
+
 static void save_opts(struct replay_opts *opts)
 {
 	const char *opts_file = git_path(SEQ_OPTS_FILE);
@@ -987,6 +1101,8 @@ static void save_opts(struct replay_opts *opts)
 							"options.strategy-option",
 							opts->xopts[i], "^$", 0);
 	}
+	if (opts->copy_notes)
+		git_config_set_in_file(opts_file, "options.copy-notes", "true");
 }
 
 static int pick_commits(struct commit_list *todo_list, struct replay_opts *opts)
@@ -1003,10 +1119,16 @@ static int pick_commits(struct commit_list *todo_list, struct replay_opts *opts)
 	for (cur = todo_list; cur; cur = cur->next) {
 		save_todo(cur, opts);
 		res = do_pick_commit(cur->item, opts);
-		if (res)
+		if (res) {
+			if (opts->copy_notes)
+				save_rewritten();
 			return res;
+		}
 	}
 
+	if (opts->copy_notes)
+		copy_notes();
+
 	/*
 	 * Sequence of picks finished successfully; cleanup by
 	 * removing the .git/sequencer directory
@@ -1033,6 +1155,8 @@ static int sequencer_continue(struct replay_opts *opts)
 		return continue_single_pick();
 	read_populate_opts(&opts);
 	read_populate_todo(&todo_list, opts);
+	if (opts->copy_notes)
+		read_populate_rewritten();
 
 	/* Verify that the conflict has been resolved */
 	if (file_exists(git_path("CHERRY_PICK_HEAD")) ||
@@ -1049,8 +1173,14 @@ static int sequencer_continue(struct replay_opts *opts)
 
 static int single_pick(struct commit *cmit, struct replay_opts *opts)
 {
+	int ret;
 	setenv(GIT_REFLOG_ACTION, action_name(opts), 0);
-	return do_pick_commit(cmit, opts);
+	ret = do_pick_commit(cmit, opts);
+	if (ret)
+		return ret;
+	if (opts->copy_notes)
+		copy_notes();
+	return 0;
 }
 
 int sequencer_pick_revisions(struct replay_opts *opts)
diff --git a/sequencer.h b/sequencer.h
index 3b04844..6cc072c 100644
--- a/sequencer.h
+++ b/sequencer.h
@@ -5,6 +5,7 @@
 #define SEQ_HEAD_FILE	"sequencer/head"
 #define SEQ_TODO_FILE	"sequencer/todo"
 #define SEQ_OPTS_FILE	"sequencer/opts"
+#define SEQ_REWR_FILE	"sequencer/rewritten"
 
 #define APPEND_SIGNOFF_DEDUP (1u << 0)
 
@@ -35,6 +36,7 @@ struct replay_opts {
 	int allow_empty_message;
 	int keep_redundant_commits;
 	int skip_empty;
+	int copy_notes;
 
 	int mainline;
 
diff --git a/t/t3500-cherry.sh b/t/t3500-cherry.sh
index f038f34..79c1219 100755
--- a/t/t3500-cherry.sh
+++ b/t/t3500-cherry.sh
@@ -55,4 +55,36 @@ test_expect_success \
      expr "$(echo $(git cherry master my-topic-branch) )" : "+ [^ ]* - .*"
 '
 
+test_expect_success \
+    'copy notes' \
+    'git checkout master &&
+    echo notes > C &&
+    test_tick &&
+    git commit -a -m "Update C" &&
+    git notes add -m "a note" &&
+    git checkout -b note-test HEAD^ &&
+    git cherry-pick --copy-notes -x master &&
+    test "a note" = "$(git notes show HEAD)"
+'
+
+test_expect_success \
+    'copy multiple notes' \
+    'git checkout master &&
+    echo "multiple notes" > C &&
+    git commit -a -m "Update C again" &&
+    git notes add -m "another note" &&
+    git commit -a -m "Empty" --allow-empty &&
+    echo "more notes" > C &&
+    git commit -a -m "Update C once more" &&
+    git notes add -m "final note" &&
+    git checkout note-test &&
+    git reset --hard master~3 &&
+    test_expect_code 1 git cherry-pick --copy-notes -x HEAD..master &&
+    git reset --hard &&
+    git cherry-pick --continue
+    test "a note" = "$(git notes show HEAD~2)" &&
+    test "another note" = "$(git notes show HEAD~1)" &&
+    test "final note" = "$(git notes show HEAD)"
+'
+
 test_done
-- 
1.8.3.rc3.312.g47657de