[PATCH 15/16] cherry-pick: add a label for ancestor

@@ -73,11 +73,11 @@ static void parse_args(int argc, const char **argv)
 		exit(1);
 }
 
-static char *get_oneline(const char *message, int revert, char **body)
+static char *get_oneline(const char *message, char **body, char **parent)
 {
 	char *result, *q;
-	const char *p = message, *prefix, *abbrev, *eol;
-	int prefix_len, abbrev_len, oneline_len;
+	const char *p = message, *abbrev, *eol;
+	int abbrev_len, oneline_len;
 
 	if (!p)
 		die ("Could not read commit message of %s",

@@ -91,14 +91,12 @@ static char *get_oneline(const char *message, int revert, char **body)
 			; /* do nothing */
 	} else
 		eol = p;
-	prefix = revert ? "parent of " : "";
-	prefix_len = revert ? strlen("parent of ") : 0;
 	abbrev = find_unique_abbrev(commit->object.sha1, DEFAULT_ABBREV);
 	abbrev_len = strlen(abbrev);
 	oneline_len = eol - p;
-	q = result = xmalloc(prefix_len + abbrev_len +
-			     strlen("... ") + oneline_len + 1);
-	q = mempcpy(q, prefix, prefix_len);
+	*parent = q = xmalloc(strlen("parent of ") + abbrev_len +
+			      strlen("... ") + oneline_len + 1);
+	result = q = mempcpy(q, "parent of ", strlen("parent of "));
 	q = mempcpy(q, abbrev, abbrev_len);
 	*body = q = mempcpy(q, "... ", strlen("... "));
 	q = mempcpy(q, p, oneline_len);

@@ -252,8 +250,10 @@ static int revert_or_cherry_pick(int argc, const char **argv)
 {
 	unsigned char head[20];
 	struct commit *base, *next, *parent;
+	const char *base_label, *next_label;
 	int i, index_fd, clean;
-	char *oneline, *oneline_body, *reencoded_message = NULL;
+	char *oneline, *oneline_body, *parent_label;
+	char *reencoded_message = NULL;
 	const char *message, *encoding;
 	char *defmsg = git_pathdup("MERGE_MSG");
 	struct merge_options o;

@@ -345,11 +345,13 @@ static int revert_or_cherry_pick(int argc, const char **argv)
 					git_commit_encoding, encoding)))
 		message = reencoded_message;
 
-	oneline = get_oneline(message, action == REVERT, &oneline_body);
+	oneline = get_oneline(message, &oneline_body, &parent_label);
 
 	if (action == REVERT) {
 		base = commit;
+		base_label = oneline;
 		next = parent;
+		next_label = parent_label;
 		add_to_msg("Revert \"");
 		add_to_msg(oneline_body);
 		add_to_msg("\"\n\nThis reverts commit ");

@@ -362,7 +364,9 @@ static int revert_or_cherry_pick(int argc, const char **argv)
 		add_to_msg(".\n");
 	} else {
 		base = parent;
+		base_label = parent_label;
 		next = commit;
+		next_label = oneline;
 		set_author_ident_env(message);
 		add_message_to_msg(message);
 		if (no_replay) {

@@ -374,8 +378,9 @@ 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 = oneline;
+	o.branch2 = next ? next_label : "(empty tree)";
 
 	head_tree = parse_tree_indirect(head);
 	next_tree = next ? next->tree : empty_tree();

@@ -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