path: refactor repo_submodule_path() family of functions

As explained in an earlier commit, we're refactoring path-related
functions to provide a consistent interface for computing paths into the
commondir, gitdir and worktree. Refactor the "submodule" family of
functions accordingly.

Note that in contrast to the other `repo_*_path()` families, we have to
pass in the repository as a non-constant pointer. This is because we end
up calling `repo_read_gitmodules()` deep down in the callstack, which
may end up modifying the repository.

Signed-off-by: Patrick Steinhardt <ps@pks.im>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

builtin/submodule--helper.c

@@ -1826,7 +1826,7 @@ static int clone_submodule(const struct module_clone_data *clone_data,
 
 	connect_work_tree_and_git_dir(clone_data_path, sm_gitdir, 0);
 
-	p = git_pathdup_submodule(clone_data_path, "config");
+	p = repo_submodule_path(the_repository, clone_data_path, "config");
 	if (!p)
 		die(_("could not get submodule directory for '%s'"), clone_data_path);
 

path.c

@@ -560,14 +560,15 @@ const char *repo_worktree_path_replace(const struct repository *repo,
 }
 
 /* Returns 0 on success, negative on failure. */
-static int do_submodule_path(struct strbuf *buf, const char *path,
+static int do_submodule_path(struct repository *repo,
+			     struct strbuf *buf, const char *path,
 			     const char *fmt, va_list args)
 {
 	struct strbuf git_submodule_common_dir = STRBUF_INIT;
 	struct strbuf git_submodule_dir = STRBUF_INIT;
 	int ret;
 
-	ret = submodule_to_gitdir(the_repository, &git_submodule_dir, path);
+	ret = submodule_to_gitdir(repo, &git_submodule_dir, path);
 	if (ret)
 		goto cleanup;
 
@@ -586,13 +587,14 @@ cleanup:
 	return ret;
 }
 
-char *git_pathdup_submodule(const char *path, const char *fmt, ...)
+char *repo_submodule_path(struct repository *repo,
+			  const char *path, const char *fmt, ...)
 {
 	int err;
 	va_list args;
 	struct strbuf buf = STRBUF_INIT;
 	va_start(args, fmt);
-	err = do_submodule_path(&buf, path, fmt, args);
+	err = do_submodule_path(repo, &buf, path, fmt, args);
 	va_end(args);
 	if (err) {
 		strbuf_release(&buf);
@@ -601,16 +603,35 @@ char *git_pathdup_submodule(const char *path, const char *fmt, ...)
 	return strbuf_detach(&buf, NULL);
 }
 
-int strbuf_git_path_submodule(struct strbuf *buf, const char *path,
+const char *repo_submodule_path_append(struct repository *repo,
-			      const char *fmt, ...)
+				       struct strbuf *buf,
+				       const char *path,
+				       const char *fmt, ...)
 {
 	int err;
 	va_list args;
 	va_start(args, fmt);
-	err = do_submodule_path(buf, path, fmt, args);
+	err = do_submodule_path(repo, buf, path, fmt, args);
 	va_end(args);
+	if (err)
+		return NULL;
+	return buf->buf;
+}
 
-	return err;
+const char *repo_submodule_path_replace(struct repository *repo,
+					struct strbuf *buf,
+					const char *path,
+					const char *fmt, ...)
+{
+	int err;
+	va_list args;
+	strbuf_reset(buf);
+	va_start(args, fmt);
+	err = do_submodule_path(repo, buf, path, fmt, args);
+	va_end(args);
+	if (err)
+		return NULL;
+	return buf->buf;
 }
 
 void repo_common_pathv(const struct repository *repo,

path.h

@@ -93,20 +93,26 @@ const char *repo_worktree_path_replace(const struct repository *repo,
 	__attribute__((format (printf, 3, 4)));
 
 /*
- * Return a path into a submodule's git directory located at `path`.  `path`
+ * The `repo_submodule_path` family of functions will construct a path into a
- * must only reference a submodule of the main repository (the_repository).
+ * submodule's git directory located at `path`. `path` must be a submodule path
+ * as found in the index and must be part of the given repository.
+ *
+ * Returns a `NULL` pointer in case the submodule cannot be found.
  */
-char *git_pathdup_submodule(const char *path, const char *fmt, ...)
+char *repo_submodule_path(struct repository *repo,
-	__attribute__((format (printf, 2, 3)));
+			  const char *path,
-
+			  const char *fmt, ...)
-/*
- * Construct a path into a submodule's git directory located at `path` and
- * append it to the provided buffer `sb`.  `path` must only reference a
- * submodule of the main repository (the_repository).
- */
-int strbuf_git_path_submodule(struct strbuf *sb, const char *path,
-				     const char *fmt, ...)
 	__attribute__((format (printf, 3, 4)));
+const char *repo_submodule_path_append(struct repository *repo,
+				       struct strbuf *sb,
+				       const char *path,
+				       const char *fmt, ...)
+	__attribute__((format (printf, 4, 5)));
+const char *repo_submodule_path_replace(struct repository *repo,
+					struct strbuf *sb,
+					const char *path,
+					const char *fmt, ...)
+	__attribute__((format (printf, 4, 5)));
 
 void report_linked_checkout_garbage(struct repository *r);
 

t/helper/test-ref-store.c

@@ -75,11 +75,10 @@ static const char **get_store(const char **argv, struct ref_store **refs)
 		*refs = get_main_ref_store(the_repository);
 	} else if (skip_prefix(argv[0], "submodule:", &gitdir)) {
 		struct strbuf sb = STRBUF_INIT;
-		int ret;
 
-		ret = strbuf_git_path_submodule(&sb, gitdir, "objects/");
+		if (!repo_submodule_path_append(the_repository,
-		if (ret)
+						&sb, gitdir, "objects/"))
-			die("strbuf_git_path_submodule failed: %d", ret);
+			die("computing submodule path failed");
 		add_to_alternates_memory(sb.buf);
 		strbuf_release(&sb);
 

worktree.c

@@ -487,7 +487,8 @@ int submodule_uses_worktrees(const char *path)
 	int ret = 0;
 	struct repository_format format = REPOSITORY_FORMAT_INIT;
 
-	submodule_gitdir = git_pathdup_submodule(path, "%s", "");
+	submodule_gitdir = repo_submodule_path(the_repository,
+					       path, "%s", "");
 	if (!submodule_gitdir)
 		return 0;