submodule-config: allow submodule_free to handle arbitrary repositories

At some point we may want to rename the function so that it describes what
it actually does as 'submodule_free' doesn't quite describe that this
clears a repository's submodule cache.  But that's beyond the scope of
this series.

While at it remove the extern key word from its declaration.

Signed-off-by: Stefan Beller <sbeller@google.com>
Reviewed-by: Jonathan Tan <jonathantanmy@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

Documentation/technical/api-submodule-config.txt

@@ -38,7 +38,7 @@ Data Structures
 Functions
 ---------
 
-`void submodule_free()`::
+`void submodule_free(struct repository *r)`::
 
 	Use these to free the internally cached values.
 

builtin/grep.c

@@ -643,7 +643,7 @@ static int grep_objects(struct grep_opt *opt, const struct pathspec *pathspec,
 
 		/* load the gitmodules file for this rev */
 		if (recurse_submodules) {
-			submodule_free();
+			submodule_free(the_repository);
 			gitmodules_config_oid(&real_obj->oid);
 		}
 		if (grep_object(opt, pathspec, real_obj, list->objects[i].name,

submodule-config.c

@@ -642,8 +642,8 @@ const struct submodule *submodule_from_cache(struct repository *repo,
 			   key, lookup_path);
 }
 
-void submodule_free(void)
+void submodule_free(struct repository *r)
 {
-	if (the_repository->submodule_cache)
-		submodule_cache_clear(the_repository->submodule_cache);
+	if (r->submodule_cache)
+		submodule_cache_clear(r->submodule_cache);
 }

submodule-config.h

@@ -46,6 +46,6 @@ extern const struct submodule *submodule_from_path(
 extern const struct submodule *submodule_from_cache(struct repository *repo,
 						    const struct object_id *treeish_name,
 						    const char *key);
-extern void submodule_free(void);
+void submodule_free(struct repository *r);
 
 #endif /* SUBMODULE_CONFIG_H */

t/helper/test-submodule-config.c

@@ -64,7 +64,7 @@ int cmd_main(int argc, const char **argv)
 		arg += 2;
 	}
 
-	submodule_free();
+	submodule_free(the_repository);
 
 	return 0;
 }

unpack-trees.c

@@ -290,7 +290,7 @@ static void load_gitmodules_file(struct index_state *index,
 		if (!state && ce->ce_flags & CE_WT_REMOVE) {
 			repo_read_gitmodules(the_repository);
 		} else if (state && (ce->ce_flags & CE_UPDATE)) {
-			submodule_free();
+			submodule_free(the_repository);
 			checkout_entry(ce, state, NULL);
 			repo_read_gitmodules(the_repository);
 		}