push: Don't push a repository with unpushed submodules

When working with submodules it is easy to forget to push a
submodule to the server but pushing a super-project that
contains a commit for that submodule. The result is that the
superproject points at a submodule commit that is not available
on the server.

This adds the option --recurse-submodules=check to push. When
using this option git will check that all submodule commits that
are about to be pushed are present on a remote of the submodule.

To be able to use a combined diff, disabling a diff callback has
been removed from combined-diff.c.

Signed-off-by: Fredrik Gustafsson <iveqy@iveqy.com>
Mentored-by: Jens Lehmann <Jens.Lehmann@web.de>
Mentored-by: Heiko Voigt <hvoigt@hvoigt.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

7 files changed, 231 insertions, 0 deletions

diff --git a/Documentation/git-push.txt b/Documentation/git-push.txt
index 88acfcd4cc..6ae6ba3c2e 100644
--- a/Documentation/git-push.txt
+++ b/Documentation/git-push.txt
@@ -162,6 +162,12 @@ useful if you write an alias or script around 'git push'.
 	is specified. This flag forces progress status even if the
 	standard error stream is not directed to a terminal.
 
+--recurse-submodules=check::
+	Check whether all submodule commits used by the revisions to be
+	pushed are available on a remote tracking branch. Otherwise the
+	push will be aborted and the command will exit with non-zero status.
+
+
 include::urls-remotes.txt[]
 
 OUTPUT
diff --git a/builtin/push.c b/builtin/push.c
index 9cebf9ea23..35cce532f2 100644
--- a/builtin/push.c
+++ b/builtin/push.c
@@ -8,6 +8,7 @@
 #include "remote.h"
 #include "transport.h"
 #include "parse-options.h"
+#include "submodule.h"
 
 static const char * const push_usage[] = {
 	"git push [<options>] [<repository> [<refspec>...]]",
@@ -219,6 +220,21 @@ static int do_push(const char *repo, int flags)
 	return !!errs;
 }
 
+static int option_parse_recurse_submodules(const struct option *opt,
+				   const char *arg, int unset)
+{
+	int *flags = opt->value;
+	if (arg) {
+		if (!strcmp(arg, "check"))
+			*flags |= TRANSPORT_RECURSE_SUBMODULES_CHECK;
+		else
+			die("bad %s argument: %s", opt->long_name, arg);
+	} else
+		die("option %s needs an argument (check)", opt->long_name);
+
+	return 0;
+}
+
 int cmd_push(int argc, const char **argv, const char *prefix)
 {
 	int flags = 0;
@@ -236,6 +252,9 @@ int cmd_push(int argc, const char **argv, const char *prefix)
 		OPT_BIT('n' , "dry-run", &flags, "dry run", TRANSPORT_PUSH_DRY_RUN),
 		OPT_BIT( 0,  "porcelain", &flags, "machine-readable output", TRANSPORT_PUSH_PORCELAIN),
 		OPT_BIT('f', "force", &flags, "force updates", TRANSPORT_PUSH_FORCE),
+		{ OPTION_CALLBACK, 0, "recurse-submodules", &flags, "check",
+			"controls recursive pushing of submodules",
+			PARSE_OPT_OPTARG, option_parse_recurse_submodules },
 		OPT_BOOLEAN( 0 , "thin", &thin, "use thin pack"),
 		OPT_STRING( 0 , "receive-pack", &receivepack, "receive-pack", "receive pack program"),
 		OPT_STRING( 0 , "exec", &receivepack, "receive-pack", "receive pack program"),
diff --git a/submodule.c b/submodule.c
index 1ba9646d34..45f508c6fd 100644
--- a/submodule.c
+++ b/submodule.c
@@ -308,6 +308,114 @@ void set_config_fetch_recurse_submodules(int value)
 	config_fetch_recurse_submodules = value;
 }
 
+static int has_remote(const char *refname, const unsigned char *sha1, int flags, void *cb_data)
+{
+	return 1;
+}
+
+static int submodule_needs_pushing(const char *path, const unsigned char sha1[20])
+{
+	if (add_submodule_odb(path) || !lookup_commit_reference(sha1))
+		return 0;
+
+	if (for_each_remote_ref_submodule(path, has_remote, NULL) > 0) {
+		struct child_process cp;
+		const char *argv[] = {"rev-list", NULL, "--not", "--remotes", "-n", "1" , NULL};
+		struct strbuf buf = STRBUF_INIT;
+		int needs_pushing = 0;
+
+		argv[1] = sha1_to_hex(sha1);
+		memset(&cp, 0, sizeof(cp));
+		cp.argv = argv;
+		cp.env = local_repo_env;
+		cp.git_cmd = 1;
+		cp.no_stdin = 1;
+		cp.out = -1;
+		cp.dir = path;
+		if (start_command(&cp))
+			die("Could not run 'git rev-list %s --not --remotes -n 1' command in submodule %s",
+				sha1_to_hex(sha1), path);
+		if (strbuf_read(&buf, cp.out, 41))
+			needs_pushing = 1;
+		finish_command(&cp);
+		close(cp.out);
+		strbuf_release(&buf);
+		return needs_pushing;
+	}
+
+	return 0;
+}
+
+static void collect_submodules_from_diff(struct diff_queue_struct *q,
+					 struct diff_options *options,
+					 void *data)
+{
+	int i;
+	int *needs_pushing = data;
+
+	for (i = 0; i < q->nr; i++) {
+		struct diff_filepair *p = q->queue[i];
+		if (!S_ISGITLINK(p->two->mode))
+			continue;
+		if (submodule_needs_pushing(p->two->path, p->two->sha1)) {
+			*needs_pushing = 1;
+			break;
+		}
+	}
+}
+
+
+static void commit_need_pushing(struct commit *commit, struct commit_list *parent, int *needs_pushing)
+{
+	const unsigned char (*parents)[20];
+	unsigned int i, n;
+	struct rev_info rev;
+
+	n = commit_list_count(parent);
+	parents = xmalloc(n * sizeof(*parents));
+
+	for (i = 0; i < n; i++) {
+		hashcpy((unsigned char *)(parents + i), parent->item->object.sha1);
+		parent = parent->next;
+	}
+
+	init_revisions(&rev, NULL);
+	rev.diffopt.output_format |= DIFF_FORMAT_CALLBACK;
+	rev.diffopt.format_callback = collect_submodules_from_diff;
+	rev.diffopt.format_callback_data = needs_pushing;
+	diff_tree_combined(commit->object.sha1, parents, n, 1, &rev);
+
+	free(parents);
+}
+
+int check_submodule_needs_pushing(unsigned char new_sha1[20], const char *remotes_name)
+{
+	struct rev_info rev;
+	struct commit *commit;
+	const char *argv[] = {NULL, NULL, "--not", "NULL", NULL};
+	int argc = ARRAY_SIZE(argv) - 1;
+	char *sha1_copy;
+	int needs_pushing = 0;
+	struct strbuf remotes_arg = STRBUF_INIT;
+
+	strbuf_addf(&remotes_arg, "--remotes=%s", remotes_name);
+	init_revisions(&rev, NULL);
+	sha1_copy = xstrdup(sha1_to_hex(new_sha1));
+	argv[1] = sha1_copy;
+	argv[3] = remotes_arg.buf;
+	setup_revisions(argc, argv, &rev, NULL);
+	if (prepare_revision_walk(&rev))
+		die("revision walk setup failed");
+
+	while ((commit = get_revision(&rev)) && !needs_pushing)
+		commit_need_pushing(commit, commit->parents, &needs_pushing);
+
+	free(sha1_copy);
+	strbuf_release(&remotes_arg);
+
+	return needs_pushing;
+}
+
 static int is_submodule_commit_present(const char *path, unsigned char sha1[20])
 {
 	int is_present = 0;
diff --git a/submodule.h b/submodule.h
index 5350b0d5a0..799c22d6c6 100644
--- a/submodule.h
+++ b/submodule.h
@@ -29,5 +29,6 @@ int fetch_populated_submodules(int num_options, const char **options,
 unsigned is_submodule_modified(const char *path, int ignore_untracked);
 int merge_submodule(unsigned char result[20], const char *path, const unsigned char base[20],
 		    const unsigned char a[20], const unsigned char b[20]);
+int check_submodule_needs_pushing(unsigned char new_sha1[20], const char *remotes_name);
 
 #endif
diff --git a/t/t5531-deep-submodule-push.sh b/t/t5531-deep-submodule-push.sh
index faa2e96337..30bec4b5f9 100755
--- a/t/t5531-deep-submodule-push.sh
+++ b/t/t5531-deep-submodule-push.sh
@@ -32,4 +32,91 @@ test_expect_success push '
 	)
 '
 
+test_expect_success 'push if submodule has no remote' '
+	(
+		cd work/gar/bage &&
+		>junk2 &&
+		git add junk2 &&
+		git commit -m "Second junk"
+	) &&
+	(
+		cd work &&
+		git add gar/bage &&
+		git commit -m "Second commit for gar/bage" &&
+		git push --recurse-submodules=check ../pub.git master
+	)
+'
+
+test_expect_success 'push fails if submodule commit not on remote' '
+	(
+		cd work/gar &&
+		git clone --bare bage ../../submodule.git &&
+		cd bage &&
+		git remote add origin ../../../submodule.git &&
+		git fetch &&
+		>junk3 &&
+		git add junk3 &&
+		git commit -m "Third junk"
+	) &&
+	(
+		cd work &&
+		git add gar/bage &&
+		git commit -m "Third commit for gar/bage" &&
+		test_must_fail git push --recurse-submodules=check ../pub.git master
+	)
+'
+
+test_expect_success 'push succeeds after commit was pushed to remote' '
+	(
+		cd work/gar/bage &&
+		git push origin master
+	) &&
+	(
+		cd work &&
+		git push --recurse-submodules=check ../pub.git master
+	)
+'
+
+test_expect_success 'push fails when commit on multiple branches if one branch has no remote' '
+	(
+		cd work/gar/bage &&
+		>junk4 &&
+		git add junk4 &&
+		git commit -m "Fourth junk"
+	) &&
+	(
+		cd work &&
+		git branch branch2 &&
+		git add gar/bage &&
+		git commit -m "Fourth commit for gar/bage" &&
+		git checkout branch2 &&
+		(
+			cd gar/bage &&
+			git checkout HEAD~1
+		) &&
+		>junk1 &&
+		git add junk1 &&
+		git commit -m "First junk" &&
+		test_must_fail git push --recurse-submodules=check ../pub.git
+	)
+'
+
+test_expect_success 'push succeeds if submodule has no remote and is on the first superproject commit' '
+	git init --bare a
+	git clone a a1 &&
+	(
+		cd a1 &&
+		git init b
+		(
+			cd b &&
+			>junk &&
+			git add junk &&
+			git commit -m "initial"
+		) &&
+		git add b &&
+		git commit -m "added submodule" &&
+		git push --recurse-submodule=check origin master
+	)
+'
+
 test_done
diff --git a/transport.c b/transport.c
index c9c8056f9d..fa279d531f 100644
--- a/transport.c
+++ b/transport.c
@@ -10,6 +10,7 @@
 #include "refs.h"
 #include "branch.h"
 #include "url.h"
+#include "submodule.h"
 
 /* rsync support */
 
@@ -1041,6 +1042,14 @@ int transport_push(struct transport *transport,
 			flags & TRANSPORT_PUSH_MIRROR,
 			flags & TRANSPORT_PUSH_FORCE);
 
+		if ((flags & TRANSPORT_RECURSE_SUBMODULES_CHECK) && !is_bare_repository()) {
+			struct ref *ref = remote_refs;
+			for (; ref; ref = ref->next)
+				if (!is_null_sha1(ref->new_sha1) &&
+				    check_submodule_needs_pushing(ref->new_sha1,transport->remote->name))
+					die("There are unpushed submodules, aborting.");
+		}
+
 		push_ret = transport->push_refs(transport, remote_refs, flags);
 		err = push_had_errors(remote_refs);
 		ret = push_ret | err;
diff --git a/transport.h b/transport.h
index 161d724bba..059b3303e2 100644
--- a/transport.h
+++ b/transport.h
@@ -101,6 +101,7 @@ struct transport {
 #define TRANSPORT_PUSH_MIRROR 8
 #define TRANSPORT_PUSH_PORCELAIN 16
 #define TRANSPORT_PUSH_SET_UPSTREAM 32
+#define TRANSPORT_RECURSE_SUBMODULES_CHECK 64
 
 #define TRANSPORT_SUMMARY_WIDTH (2 * DEFAULT_ABBREV + 3)