Merge branch 'ao/submodule-wo-gitmodules-checked-out'

The submodule support has been updated to read from the blob at
HEAD:.gitmodules when the .gitmodules file is missing from the
working tree.

* ao/submodule-wo-gitmodules-checked-out:
  t/helper: add test-submodule-nested-repo-config
  submodule: support reading .gitmodules when it's not in the working tree
  submodule: add a helper to check if it is safe to write to .gitmodules
  t7506: clean up .gitmodules properly before setting up new scenario
  submodule: use the 'submodule--helper config' command
  submodule--helper: add a new 'config' subcommand
  t7411: be nicer to future tests and really clean things up
  t7411: merge tests 5 and 6
  submodule: factor out a config_set_in_gitmodules_file_gently function
  submodule: add a print_config_from_gitmodules() helper

2 files changed, 54 insertions, 3 deletions

diff --git a/builtin/grep.c b/builtin/grep.c
index d8508ddf79..56e4a11052 100644
--- a/builtin/grep.c
+++ b/builtin/grep.c
@@ -422,11 +422,23 @@ static int grep_submodule(struct grep_opt *opt, struct repository *superproject,
 	struct repository submodule;
 	int hit;
 
-	if (!is_submodule_active(superproject, path))
+	/*
+	 * NEEDSWORK: submodules functions need to be protected because they
+	 * access the object store via config_from_gitmodules(): the latter
+	 * uses get_oid() which, for now, relies on the global the_repository
+	 * object.
+	 */
+	grep_read_lock();
+
+	if (!is_submodule_active(superproject, path)) {
+		grep_read_unlock();
 		return 0;
+	}
 
-	if (repo_submodule_init(&submodule, superproject, path))
+	if (repo_submodule_init(&submodule, superproject, path)) {
+		grep_read_unlock();
 		return 0;
+	}
 
 	repo_read_gitmodules(&submodule);
 
@@ -440,7 +452,6 @@ static int grep_submodule(struct grep_opt *opt, struct repository *superproject,
 	 * store is no longer global and instead is a member of the repository
 	 * object.
 	 */
-	grep_read_lock();
 	add_to_alternates_memory(submodule.objects->objectdir);
 	grep_read_unlock();
 
diff --git a/builtin/submodule--helper.c b/builtin/submodule--helper.c
index 676175b9be..d38113a31a 100644
--- a/builtin/submodule--helper.c
+++ b/builtin/submodule--helper.c
@@ -2141,6 +2141,45 @@ static int check_name(int argc, const char **argv, const char *prefix)
 	return 0;
 }
 
+static int module_config(int argc, const char **argv, const char *prefix)
+{
+	enum {
+		CHECK_WRITEABLE = 1
+	} command = 0;
+
+	struct option module_config_options[] = {
+		OPT_CMDMODE(0, "check-writeable", &command,
+			    N_("check if it is safe to write to the .gitmodules file"),
+			    CHECK_WRITEABLE),
+		OPT_END()
+	};
+	const char *const git_submodule_helper_usage[] = {
+		N_("git submodule--helper config name [value]"),
+		N_("git submodule--helper config --check-writeable"),
+		NULL
+	};
+
+	argc = parse_options(argc, argv, prefix, module_config_options,
+			     git_submodule_helper_usage, PARSE_OPT_KEEP_ARGV0);
+
+	if (argc == 1 && command == CHECK_WRITEABLE)
+		return is_writing_gitmodules_ok() ? 0 : -1;
+
+	/* Equivalent to ACTION_GET in builtin/config.c */
+	if (argc == 2)
+		return print_config_from_gitmodules(the_repository, argv[1]);
+
+	/* Equivalent to ACTION_SET in builtin/config.c */
+	if (argc == 3) {
+		if (!is_writing_gitmodules_ok())
+			die(_("please make sure that the .gitmodules file is in the working tree"));
+
+		return config_set_in_gitmodules_file_gently(argv[1], argv[2]);
+	}
+
+	usage_with_options(git_submodule_helper_usage, module_config_options);
+}
+
 #define SUPPORT_SUPER_PREFIX (1<<0)
 
 struct cmd_struct {
@@ -2170,6 +2209,7 @@ static struct cmd_struct commands[] = {
 	{"absorb-git-dirs", absorb_git_dirs, SUPPORT_SUPER_PREFIX},
 	{"is-active", is_active, 0},
 	{"check-name", check_name, 0},
+	{"config", module_config, 0},
 };
 
 int cmd_submodule__helper(int argc, const char **argv, const char *prefix)