[PATCH 2/2] push: fix --dry-run to not push submodules

[Brandon Williams <bmwill@google.com>]

Teach push to respect the --dry-run option when configured to
recursively push submodules 'on-demand'.  This is done by passing the
--dry-run flag to the child process which performs a push for a
submodules when performing a dry-run.

In order to preserve good user experience, the additional check for
unpushed submodules is skipped during a dry-run when
--recurse-submodules=on-demand.  The check is skipped because the submodule
pushes were performed as dry-runs and this check would always fail as the
submodules would still need to be pushed.

Signed-off-by: Brandon Williams <bmwill@google.com>
---
 submodule.c                    | 13 ++++++++-----
 submodule.h                    |  4 +++-
 t/t5531-deep-submodule-push.sh |  2 +-
 transport.c                    |  9 ++++++---
 4 files changed, 18 insertions(+), 10 deletions(-)

diff --git a/submodule.c b/submodule.c
index a05c2a3..7b9bed1 100644
--- a/submodule.c
+++ b/submodule.c
@@ -676,16 +676,17 @@ int find_unpushed_submodules(struct sha1_array *hashes,
 	return needs_pushing->nr;
 }
 
-static int push_submodule(const char *path)
+static int push_submodule(const char *path, int dry_run)
 {
 	if (add_submodule_odb(path))
 		return 1;
 
 	if (for_each_remote_ref_submodule(path, has_remote, NULL) > 0) {
 		struct child_process cp = CHILD_PROCESS_INIT;
-		const char *argv[] = {"push", NULL};
+		argv_array_push(&cp.args, "push");
+		if (dry_run)
+			argv_array_push(&cp.args, "--dry-run");
 
-		cp.argv = argv;
 		prepare_submodule_repo_env(&cp.env_array);
 		cp.git_cmd = 1;
 		cp.no_stdin = 1;
@@ -698,7 +699,9 @@ static int push_submodule(const char *path)
 	return 1;
 }
 
-int push_unpushed_submodules(struct sha1_array *hashes, const char *remotes_name)
+int push_unpushed_submodules(struct sha1_array *hashes,
+			     const char *remotes_name,
+			     int dry_run)
 {
 	int i, ret = 1;
 	struct string_list needs_pushing = STRING_LIST_INIT_DUP;
@@ -709,7 +712,7 @@ int push_unpushed_submodules(struct sha1_array *hashes, const char *remotes_name
 	for (i = 0; i < needs_pushing.nr; i++) {
 		const char *path = needs_pushing.items[i].string;
 		fprintf(stderr, "Pushing submodule '%s'\n", path);
-		if (!push_submodule(path)) {
+		if (!push_submodule(path, dry_run)) {
 			fprintf(stderr, "Unable to push submodule '%s'\n", path);
 			ret = 0;
 		}
diff --git a/submodule.h b/submodule.h
index 065b2f0..a38e0f3 100644
--- a/submodule.h
+++ b/submodule.h
@@ -65,7 +65,9 @@ int merge_submodule(unsigned char result[20], const char *path, const unsigned c
 		    const unsigned char a[20], const unsigned char b[20], int search);
 int find_unpushed_submodules(struct sha1_array *hashes, const char *remotes_name,
 		struct string_list *needs_pushing);
-int push_unpushed_submodules(struct sha1_array *hashes, const char *remotes_name);
+extern int push_unpushed_submodules(struct sha1_array *hashes,
+				    const char *remotes_name,
+				    int dry_run);
 void connect_work_tree_and_git_dir(const char *work_tree, const char *git_dir);
 int parallel_submodules(void);
 
diff --git a/t/t5531-deep-submodule-push.sh b/t/t5531-deep-submodule-push.sh
index e6ccc30..54f334c 100755
--- a/t/t5531-deep-submodule-push.sh
+++ b/t/t5531-deep-submodule-push.sh
@@ -431,7 +431,7 @@ test_expect_success 'push unpushable submodule recursively fails' '
 	git -C work reset --hard master^
 '
 
-test_expect_failure 'push --dry-run does not recursively update submodules' '
+test_expect_success 'push --dry-run does not recursively update submodules' '
 	(
 		cd work &&
 		(
diff --git a/transport.c b/transport.c
index f6bec0d..4ad08d0 100644
--- a/transport.c
+++ b/transport.c
@@ -921,15 +921,18 @@ int transport_push(struct transport *transport,
 				if (!is_null_oid(&ref->new_oid))
 					sha1_array_append(&hashes, ref->new_oid.hash);
 
-			if (!push_unpushed_submodules(&hashes, transport->remote->name)) {
+			if (!push_unpushed_submodules(&hashes,
+						      transport->remote->name,
+						      pretend)) {
 				sha1_array_clear(&hashes);
 				die ("Failed to push all needed submodules!");
 			}
 			sha1_array_clear(&hashes);
 		}
 
-		if ((flags & (TRANSPORT_RECURSE_SUBMODULES_ON_DEMAND |
-			      TRANSPORT_RECURSE_SUBMODULES_CHECK)) && !is_bare_repository()) {
+		if (((flags & TRANSPORT_RECURSE_SUBMODULES_CHECK) ||
+		     ((flags & TRANSPORT_RECURSE_SUBMODULES_ON_DEMAND) &&
+		      !pretend)) && !is_bare_repository()) {
 			struct ref *ref = remote_refs;
 			struct string_list needs_pushing = STRING_LIST_INIT_DUP;
 			struct sha1_array hashes = SHA1_ARRAY_INIT;
-- 
2.8.0.rc3.226.g39d4020