Subject: [PATCHv3 6/7] submodule--helper: add remote-branch helper

From: Stefan Beller <[email-masked]>
Date: Thu, 28 Jul 2016 17:44:08 -0700

In a later patch we want to enhance the logic for the branch selection.
Rewrite the current logic to be in C, so we can directly use C when
we enhance the logic.

Signed-off-by: Stefan Beller <[email-masked]>
---
 builtin/submodule--helper.c | 28 +++++++++++++++++++++++++++-
 git-submodule.sh            |  2 +-
 2 files changed, 28 insertions(+), 2 deletions(-)

diff --git a/builtin/submodule--helper.c b/builtin/submodule--helper.c
index fb90c64..710048f 100644
--- a/builtin/submodule--helper.c
+++ b/builtin/submodule--helper.c
@@ -899,6 +899,31 @@ static int resolve_relative_path(int argc, const char **argv, const char *prefix
 	return 0;
 }
 
+static const char *remote_submodule_branch(const char *path)
+{
+	const struct submodule *sub;
+	gitmodules_config();
+	git_config(submodule_config, NULL);
+
+	sub = submodule_from_path(null_sha1, path);
+	if (!sub->branch)
+		return "master";
+
+	return sub->branch;
+}
+
+static int resolve_remote_submodule_branch(int argc, const char **argv,
+		const char *prefix)
+{
+	struct strbuf sb = STRBUF_INIT;
+	if (argc != 2)
+		die("submodule--helper remote-branch takes exactly one arguments, got %d", argc);
+
+	printf("%s", remote_submodule_branch(argv[1]));
+	strbuf_release(&sb);
+	return 0;
+}
+
 struct cmd_struct {
 	const char *cmd;
 	int (*fn)(int, const char **, const char *);
@@ -912,7 +937,8 @@ static struct cmd_struct commands[] = {
 	{"relative-path", resolve_relative_path},
 	{"resolve-relative-url", resolve_relative_url},
 	{"resolve-relative-url-test", resolve_relative_url_test},
-	{"init", module_init}
+	{"init", module_init},
+	{"remote-branch", resolve_remote_submodule_branch}
 };
 
 int cmd_submodule__helper(int argc, const char **argv, const char *prefix)
diff --git a/git-submodule.sh b/git-submodule.sh
index 0d4021f..1e493a8 100755
--- a/git-submodule.sh
+++ b/git-submodule.sh
@@ -616,7 +616,7 @@ cmd_update()
 
 		if test -n "$remote"
 		then
-			branch=$(get_submodule_config "$name" branch master)
+			branch=$(git submodule--helper remote-branch "$sm_path")
 			if test -z "$nofetch"
 			then
 				# Fetch remote before determining tracking $sha1
-- 
2.9.2.472.g1ffb07c.dirty