replay: add --contained to rebase contained branches

Let's add a `--contained` option that can be used along with
`--onto` to rebase all the branches contained in the <revision-range>
argument.

Co-authored-by: Christian Couder <chriscool@tuxfamily.org>
Signed-off-by: Elijah Newren <newren@gmail.com>
Signed-off-by: Christian Couder <chriscool@tuxfamily.org>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

Documentation/git-replay.txt

@@ -9,7 +9,7 @@ git-replay - EXPERIMENTAL: Replay commits on a new base, works with bare repos t
 SYNOPSIS
 --------
 [verse]
-(EXPERIMENTAL!) 'git replay' (--onto <newbase> | --advance <branch>) <revision-range>...
+(EXPERIMENTAL!) 'git replay' ([--contained] --onto <newbase> | --advance <branch>) <revision-range>...
 
 DESCRIPTION
 -----------
@@ -96,6 +96,16 @@ top of the exact same new base, they only differ in that the first
 provides instructions to make mybranch point at the new commits and
 the second provides instructions to make target point at them.
 
+What if you have a stack of branches, one depending upon another, and
+you'd really like to rebase the whole set?
+
+------------
+$ git replay --contained --onto origin/main origin/main..tipbranch
+update refs/heads/branch1 ${NEW_branch1_HASH} ${OLD_branch1_HASH}
+update refs/heads/branch2 ${NEW_branch2_HASH} ${OLD_branch2_HASH}
+update refs/heads/tipbranch ${NEW_tipbranch_HASH} ${OLD_tipbranch_HASH}
+------------
+
 When calling `git replay`, one does not need to specify a range of
 commits to replay using the syntax `A..B`; any range expression will
 do:

builtin/replay.c

@@ -258,6 +258,7 @@ int cmd_replay(int argc, const char **argv, const char *prefix)
 	const char *advance_name = NULL;
 	struct commit *onto = NULL;
 	const char *onto_name = NULL;
+	int contained = 0;
 
 	struct rev_info revs;
 	struct commit *last_commit = NULL;
@@ -268,7 +269,9 @@ int cmd_replay(int argc, const char **argv, const char *prefix)
 	int ret = 0;
 
 	const char * const replay_usage[] = {
-		N_("(EXPERIMENTAL!) git replay (--onto <newbase> | --advance <branch>) <revision-range>..."),
+		N_("(EXPERIMENTAL!) git replay "
+		   "([--contained] --onto <newbase> | --advance <branch>) "
+		   "<revision-range>..."),
 		NULL
 	};
 	struct option replay_options[] = {
@@ -278,6 +281,8 @@ int cmd_replay(int argc, const char **argv, const char *prefix)
 		OPT_STRING(0, "onto", &onto_name,
 			   N_("revision"),
 			   N_("replay onto given commit")),
+		OPT_BOOL(0, "contained", &contained,
+			 N_("advance all branches contained in revision-range")),
 		OPT_END()
 	};
 
@@ -289,6 +294,10 @@ int cmd_replay(int argc, const char **argv, const char *prefix)
 		usage_with_options(replay_usage, replay_options);
 	}
 
+	if (advance_name && contained)
+		die(_("options '%s' and '%s' cannot be used together"),
+		    "--advance", "--contained");
+
 	repo_init_revisions(the_repository, &revs, prefix);
 
 	/*
@@ -377,7 +386,8 @@ int cmd_replay(int argc, const char **argv, const char *prefix)
 			continue;
 		while (decoration) {
 			if (decoration->type == DECORATION_REF_LOCAL &&
-			    strset_contains(update_refs, decoration->name)) {
+			    (contained || strset_contains(update_refs,
+							  decoration->name))) {
 				printf("update %s %s %s\n",
 				       decoration->name,
 				       oid_to_hex(&last_commit->object.oid),

t/t3650-replay-basics.sh

@@ -114,4 +114,33 @@ test_expect_success 'replay fails when both --advance and --onto are omitted' '
 	test_must_fail git replay topic1..topic2 >result
 '
 
+test_expect_success 'using replay to also rebase a contained branch' '
+	git replay --contained --onto main main..topic3 >result &&
+
+	test_line_count = 2 result &&
+	cut -f 3 -d " " result >new-branch-tips &&
+
+	git log --format=%s $(head -n 1 new-branch-tips) >actual &&
+	test_write_lines F C M L B A >expect &&
+	test_cmp expect actual &&
+
+	git log --format=%s $(tail -n 1 new-branch-tips) >actual &&
+	test_write_lines H G F C M L B A >expect &&
+	test_cmp expect actual &&
+
+	printf "update refs/heads/topic1 " >expect &&
+	printf "%s " $(head -n 1 new-branch-tips) >>expect &&
+	git rev-parse topic1 >>expect &&
+	printf "update refs/heads/topic3 " >>expect &&
+	printf "%s " $(tail -n 1 new-branch-tips) >>expect &&
+	git rev-parse topic3 >>expect &&
+
+	test_cmp expect result
+'
+
+test_expect_success 'using replay on bare repo to also rebase a contained branch' '
+	git -C bare replay --contained --onto main main..topic3 >result-bare &&
+	test_cmp expect result-bare
+'
+
 test_done