From bf975d379d79ab0eb9e8835af4abab4712e71dad Mon Sep 17 00:00:00 2001
From: Jonathan Nieder <jrnieder@gmail.com>
Date: Sat, 20 Mar 2010 19:46:07 -0500
Subject: cherry-pick, revert: add a label for ancestor
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When writing conflict hunks in ‘diff3 -m’ format, also add a label to
the common ancestor.  Especially in a cherry-pick, it is not immediately
obvious without such a label what the common ancestor represents.

git rerere does not have trouble parsing the new output and its preimage
ids are unchanged since it includes its own code for recreating conflict
hunks.  No other code in git parses conflict hunks.

Requested-by: Stefan Monnier <monnier@iro.umontreal.ca>
Signed-off-by: Jonathan Nieder <jrnieder@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

diff --git a/builtin/revert.c b/builtin/revert.c
index 5a5b721..1ddfac1 100644
--- a/builtin/revert.c
+++ b/builtin/revert.c
@@ -281,7 +281,7 @@ static int revert_or_cherry_pick(int argc, const char **argv)
 {
 	unsigned char head[20];
 	struct commit *base, *next, *parent;
-	const char *next_label;
+	const char *base_label, *next_label;
 	int i, index_fd, clean;
 	struct commit_message msg = { NULL, NULL, NULL, NULL, NULL };
 
@@ -368,6 +368,7 @@ static int revert_or_cherry_pick(int argc, const char **argv)
 
 	if (action == REVERT) {
 		base = commit;
+		base_label = msg.label;
 		next = parent;
 		next_label = msg.parent_label;
 		add_to_msg("Revert \"");
@@ -382,6 +383,7 @@ static int revert_or_cherry_pick(int argc, const char **argv)
 		add_to_msg(".\n");
 	} else {
 		base = parent;
+		base_label = msg.parent_label;
 		next = commit;
 		next_label = msg.label;
 		set_author_ident_env(msg.message);
@@ -395,6 +397,7 @@ static int revert_or_cherry_pick(int argc, const char **argv)
 
 	read_cache();
 	init_merge_options(&o);
+	o.ancestor = base ? base_label : "(empty tree)";
 	o.branch1 = "HEAD";
 	o.branch2 = next ? next_label : "(empty tree)";
 
diff --git a/t/t3507-cherry-pick-conflict.sh b/t/t3507-cherry-pick-conflict.sh
index 6a20817..e25cf80 100644
--- a/t/t3507-cherry-pick-conflict.sh
+++ b/t/t3507-cherry-pick-conflict.sh
@@ -112,7 +112,7 @@ test_expect_success 'diff3 -m style' '
 	cat <<-EOF > expected &&
 	<<<<<<< HEAD
 	a
-	|||||||
+	||||||| parent of objid picked
 	b
 	=======
 	c
@@ -179,7 +179,7 @@ test_expect_success 'revert conflict, diff3 -m style' '
 	cat <<-EOF > expected &&
 	<<<<<<< HEAD
 	a
-	|||||||
+	||||||| objid picked
 	c
 	=======
 	b
-- 
cgit v0.10.2-6-g49f6