On 05/01, Stefan Beller wrote:
> Add a new command, that reattaches a detached HEAD to its configured
> branch in a submodule.
>
> In a later patch we will teach git-submodule as well as other submodule
> worktree manipulators (git reset/checkout --recurse-submodules) to not
> end up in a detached HEAD state in the submodules.
>
> Signed-off-by: Stefan Beller <sbel...@google.com>
>
> +int reattach_HEAD(const char *submodule_path, int flags)
> +{
> + const char *branch;
> + struct object_id sub_head_object;
> + struct object_id sub_branch_object;
> +
> + const struct submodule *sub = submodule_from_path(null_sha1,
> submodule_path);
> +
> + if (!sub) {
> + if (!(flags & REATTACH_HEAD_DIE_ON_ERROR))
> + return -1;
> + die(_("no submodule mapping found in .gitmodules for path
> '%s'"),
> + submodule_path);
It may be a bit clearer to do the following:
if (flags & REATTACH_HEAD_DIE_ON_ERROR)
die(...);
return -1;
It just feels weird to me to have the inverted logic, that's my opinion
though.
> + }
> +
> + if (!sub->branch) {
> + if (!(flags & REATTACH_HEAD_DIE_ON_ERROR))
> + return -1;
> + die(_("no branch configured to follow for submodule '%s'"),
> + sub->path);
> + }
> +
> + /* lookup branch value in .gitmodules */
> + if (strcmp(".", sub->branch)) {
> + branch = sub->branch;
> + } else {
> + /* special care for '.': Is the superproject on a branch? */
> + struct object_id oid;
> + branch = resolve_refdup("HEAD", 0, oid.hash, NULL);
> + if (!branch) {
> + if (!(flags & REATTACH_HEAD_DIE_ON_ERROR))
> + return -1;
> + die(_("Not on any branch, but submodule configured to
> follow superprojects branch"));
> + }
> + }
> +
> + if (!strcmp("HEAD", branch))
> + return 0;
So this is the case where the superproject is in a detached-HEAD state?
In that case then we don't need to continue because if the superproject
isn't on a branch, then there isn't a reason the submodule should be on
a branch.
> +
> + resolve_gitlink_ref(sub->path, "HEAD", sub_head_object.hash);
> + resolve_gitlink_ref(sub->path, branch, sub_branch_object.hash);
> +
> + if (!oidcmp(&sub_head_object, &sub_branch_object)) {
> + struct child_process cp = CHILD_PROCESS_INIT;
> + struct strbuf reason = STRBUF_INIT;
> +
> + cp.dir = sub->path;
> + prepare_submodule_repo_env(&cp.env_array);
> +
> + strbuf_addf(&reason, "reattach HEAD to %s", branch);
> + argv_array_pushl(&cp.args, "git", "symbolic-ref",
> + "-m", reason.buf, "HEAD", branch, NULL);
> + if (run_command(&cp)) {
> + if (!(flags & REATTACH_HEAD_DIE_ON_ERROR))
> + return -1;
> + die(_("could not run symbolic-ref in submodule '%s'"),
> + sub->path);
> + }
> + strbuf_release(&reason);
> + return 0;
> + } else {
> + fprintf(stderr, "not reattaching HEAD, object ids differ:\n"
> + "HEAD is %s\n branch is %s",
> + oid_to_hex(&sub_head_object),
> + oid_to_hex(&sub_branch_object));
> + return 1;
> + }
> +}
> +
> static int find_first_merges(struct object_array *result, const char *path,
> struct commit *a, struct commit *b)
> {
> diff --git a/submodule.h b/submodule.h
> index 1277480add..f7bb565a6d 100644
> --- a/submodule.h
> +++ b/submodule.h
> @@ -119,6 +119,16 @@ extern int submodule_move_head(const char *path,
> */
> extern void prepare_submodule_repo_env(struct argv_array *out);
>
> +/*
> + * Attach the submodules HEAD to its configured branch if the underlying
> + * object id are the same. Returns
> + * - 0 when the branch could be reattached.
> + * - +1 when the branch could not be reattached due to object name mismatch
> + * - <0 when an error occurred (e.g. missing .gitmodules file)
> + */
> +#define REATTACH_HEAD_DIE_ON_ERROR (1<<0)
> +extern int reattach_HEAD(const char *submodule_path, int flags);
> +
> #define ABSORB_GITDIR_RECURSE_SUBMODULES (1<<0)
> extern void absorb_git_dir_into_superproject(const char *prefix,
> const char *path,
> --
> 2.13.0.rc1.1.gbc33f0f778
>
--
Brandon Williams
