submodule--helper: add remote-branch helper

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 <sbeller@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

diff --git a/builtin/submodule--helper.c b/builtin/submodule--helper.c
index fb90c64..9be2c75 100644 (file)
--- a/builtin/submodule--helper.c
+++ b/builtin/submodule--helper.c
@@ -899,6 +899,39 @@ 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)
+               return NULL;
+
+       if (!sub->branch)
+               return "master";
+
+       return sub->branch;
+}
+
+static int resolve_remote_submodule_branch(int argc, const char **argv,
+               const char *prefix)
+{
+       const char *ret;
+       struct strbuf sb = STRBUF_INIT;
+       if (argc != 2)
+               die("submodule--helper remote-branch takes exactly one arguments, got %d", argc);
+
+       ret = remote_submodule_branch(argv[1]);
+       if (!ret)
+               die("submodule %s doesn't exist", argv[1]);
+
+       printf("%s", ret);
+       strbuf_release(&sb);
+       return 0;
+}
+
 struct cmd_struct {
        const char *cmd;
        int (*fn)(int, const char **, const char *);
@@ -912,7 +945,8 @@ 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 41aff65..8c5e898 100755 (executable)
--- a/git-submodule.sh
+++ b/git-submodule.sh
@@ -614,7 +614,7 @@ 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