[PATCH] pull: optionally rebase submodules

[Brandon Williams <bmwill@google.com>]

Teach pull to optionally update submodules when '--recurse-submodules'
is provided.  This will teach pull to run 'submodule update --rebase'
when the '--recurse-submodules' and '--rebase' flags are given.

Signed-off-by: Brandon Williams <bmwill@google.com>
---

Pull is already a shortcut for running fetch followed by a merge/rebase, so why
not have it be a shortcut for running 'submodule update --rebase' when the
recurse flag is given!

 builtin/pull.c            | 30 ++++++++++++++-
 t/t5572-pull-submodule.sh | 97 +++++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 125 insertions(+), 2 deletions(-)

diff --git a/builtin/pull.c b/builtin/pull.c
index dd1a4a94e..d73d654e6 100644
--- a/builtin/pull.c
+++ b/builtin/pull.c
@@ -77,6 +77,7 @@ static const char * const pull_usage[] = {
 /* Shared options */
 static int opt_verbosity;
 static char *opt_progress;
+static int recurse_submodules;
 
 /* Options passed to git-merge or git-rebase */
 static enum rebase_type opt_rebase = -1;
@@ -532,6 +533,17 @@ static int pull_into_void(const struct object_id *merge_head,
 	return 0;
 }
 
+static int  update_submodules(void)
+{
+	struct child_process cp = CHILD_PROCESS_INIT;
+	cp.git_cmd = 1;
+
+	argv_array_pushl(&cp.args, "submodule", "update", "--recursive", NULL);
+	argv_array_push(&cp.args, "--rebase");
+
+	return run_command(&cp);
+}
+
 /**
  * Runs git-merge, returning its exit status.
  */
@@ -816,6 +828,14 @@ int cmd_pull(int argc, const char **argv, const char *prefix)
 			oidclr(&rebase_fork_point);
 	}
 
+	if (opt_recurse_submodules &&
+	    !strcmp(opt_recurse_submodules, "--recurse-submodules")) {
+		recurse_submodules = 1;
+
+		if (!opt_rebase)
+			die(_("--recurse-submodules is only valid with --rebase"));
+	}
+
 	if (run_fetch(repo, refspecs))
 		return 1;
 
@@ -862,6 +882,7 @@ int cmd_pull(int argc, const char **argv, const char *prefix)
 		die(_("Cannot rebase onto multiple branches."));
 
 	if (opt_rebase) {
+		int ret = 0;
 		struct commit_list *list = NULL;
 		struct commit *merge_head, *head;
 
@@ -871,9 +892,14 @@ int cmd_pull(int argc, const char **argv, const char *prefix)
 		if (is_descendant_of(merge_head, list)) {
 			/* we can fast-forward this without invoking rebase */
 			opt_ff = "--ff-only";
-			return run_merge();
+			ret = run_merge();
 		}
-		return run_rebase(&curr_head, merge_heads.oid, &rebase_fork_point);
+		ret = run_rebase(&curr_head, merge_heads.oid, &rebase_fork_point);
+
+		if (!ret && recurse_submodules)
+			ret = update_submodules();
+
+		return ret;
 	} else {
 		return run_merge();
 	}
diff --git a/t/t5572-pull-submodule.sh b/t/t5572-pull-submodule.sh
index accfa5cc0..234a22315 100755
--- a/t/t5572-pull-submodule.sh
+++ b/t/t5572-pull-submodule.sh
@@ -42,4 +42,101 @@ KNOWN_FAILURE_NOFF_MERGE_DOESNT_CREATE_EMPTY_SUBMODULE_DIR=1
 KNOWN_FAILURE_NOFF_MERGE_ATTEMPTS_TO_MERGE_REMOVED_SUBMODULE_FILES=1
 test_submodule_switch "git_pull_noff"
 
+test_expect_success 'pull --recurse-submodule setup' '
+	git init child &&
+	(
+		cd child &&
+		echo "bar" >file &&
+		git add file &&
+		git commit -m "initial commit"
+	) &&
+	git init parent &&
+	(
+		cd parent &&
+		echo "foo" >file &&
+		git add file &&
+		git commit -m "Initial commit" &&
+		git submodule add ../child sub &&
+		git commit -m "add submodule"
+	) &&
+	git clone --recurse-submodule parent super &&
+	git -C super/sub checkout master
+'
+
+test_expect_success 'pull recursive fails without --rebase' '
+	test_must_fail git -C super pull --recurse-submodules 2>actual &&
+	test_i18ngrep "recurse-submodules is only valid with --rebase" actual
+'
+
+test_expect_success 'pull basic recurse' '
+	(
+		cd child &&
+		echo "foobar" >>file &&
+		git add file &&
+		git commit -m "update file"
+	) &&
+	(
+		cd parent &&
+		git -C sub pull &&
+		git add sub &&
+		git commit -m "update submodule"
+	) &&
+
+	git -C parent rev-parse master >expect_super &&
+	git -C child rev-parse master >expect_sub &&
+
+	git -C super pull --rebase --recurse-submodules &&
+	git -C super rev-parse master >actual_super &&
+	git -C super/sub rev-parse master >actual_sub &&
+	test_cmp expect_super actual_super &&
+	test_cmp expect_sub actual_sub
+'
+
+test_expect_success 'pull basic rebase recurse' '
+	(
+		cd child &&
+		echo "a" >file &&
+		git add file &&
+		git commit -m "update file"
+	) &&
+	(
+		cd parent &&
+		git -C sub pull &&
+		git add sub &&
+		git commit -m "update submodule"
+	) &&
+	(
+		cd super/sub &&
+		echo "b" >file2 &&
+		git add file2 &&
+		git commit -m "add file2"
+	) &&
+
+	git -C parent rev-parse master >expect_super &&
+	git -C child rev-parse master >expect_sub &&
+
+	git -C super pull --rebase --recurse-submodules &&
+	git -C super rev-parse master >actual_super &&
+	git -C super/sub rev-parse master^ >actual_sub &&
+	test_cmp expect_super actual_super &&
+	test_cmp expect_sub actual_sub &&
+
+	echo "a" >expect &&
+	test_cmp expect super/sub/file &&
+	echo "b" >expect &&
+	test_cmp expect super/sub/file2
+'
+
+test_expect_success 'pull rebase recursing fails with conflicts' '
+	git -C super/sub reset --hard HEAD^^ &&
+	git -C super reset --hard HEAD^ &&
+	(
+		cd super/sub &&
+		echo "b" >file &&
+		git add file &&
+		git commit -m "update file"
+	) &&
+	test_must_fail git -C super pull --rebase --recurse-submodules
+'
+
 test_done
-- 
2.13.0.rc2.291.g57267f2277-goog