reset/checkout/read-tree: unify config callback for submodule recursion

The callback function is essentially duplicated 3 times. Remove all
of them and offer a new callback function, that lives in submodule.c

By putting the callback function there, we no longer need the function
'set_config_update_recurse_submodules', nor duplicate the global variable
in each builtin as well as submodule.c

In the three builtins we have different 2 ways how to load the .gitmodules
and config file, which are slightly different. git-checkout has to load
the submodule config all the time due to 23b4c7bcc5 (checkout: Use
submodule.*.ignore settings from .git/config and .gitmodules, 2010-08-28)

git-reset and git-read-tree do not respect these diff settings, so loading
the submodule configuration is optional. Also put that into submodule.c
for code deduplication.

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

5 files changed, 38 insertions, 83 deletions

diff --git a/builtin/checkout.c b/builtin/checkout.c
index da5c9dc11c..56ea723b75 100644
--- a/builtin/checkout.c
+++ b/builtin/checkout.c
@@ -21,31 +21,12 @@
 #include "submodule-config.h"
 #include "submodule.h"
 
-static int recurse_submodules = RECURSE_SUBMODULES_DEFAULT;
-
 static const char * const checkout_usage[] = {
 	N_("git checkout [<options>] <branch>"),
 	N_("git checkout [<options>] [<branch>] -- <file>..."),
 	NULL,
 };
 
-static int option_parse_recurse_submodules(const struct option *opt,
-					   const char *arg, int unset)
-{
-	if (unset) {
-		recurse_submodules = RECURSE_SUBMODULES_OFF;
-		return 0;
-	}
-	if (arg)
-		recurse_submodules =
-			parse_update_recurse_submodules_arg(opt->long_name,
-							    arg);
-	else
-		recurse_submodules = RECURSE_SUBMODULES_ON;
-
-	return 0;
-}
-
 struct checkout_opts {
 	int patch_mode;
 	int quiet;
@@ -1184,7 +1165,7 @@ int cmd_checkout(int argc, const char **argv, const char *prefix)
 			 N_("do not check if another worktree is holding the given ref")),
 		{ OPTION_CALLBACK, 0, "recurse-submodules", NULL,
 			    "checkout", "control recursive updating of submodules",
-			    PARSE_OPT_OPTARG, option_parse_recurse_submodules },
+			    PARSE_OPT_OPTARG, option_parse_recurse_submodules_worktree_updater },
 		OPT_BOOL(0, "progress", &opts.show_progress, N_("force progress reporting")),
 		OPT_END(),
 	};
@@ -1215,12 +1196,6 @@ int cmd_checkout(int argc, const char **argv, const char *prefix)
 		git_xmerge_config("merge.conflictstyle", conflict_style, NULL);
 	}
 
-	if (recurse_submodules != RECURSE_SUBMODULES_OFF) {
-		git_config(submodule_config, NULL);
-		if (recurse_submodules != RECURSE_SUBMODULES_DEFAULT)
-			set_config_update_recurse_submodules(recurse_submodules);
-	}
-
 	if ((!!opts.new_branch + !!opts.new_branch_force + !!opts.new_orphan_branch) > 1)
 		die(_("-b, -B and --orphan are mutually exclusive"));
 
diff --git a/builtin/read-tree.c b/builtin/read-tree.c
index 2a1b8a530e..8a889ef4c3 100644
--- a/builtin/read-tree.c
+++ b/builtin/read-tree.c
@@ -21,7 +21,6 @@
 static int nr_trees;
 static int read_empty;
 static struct tree *trees[MAX_UNPACK_TREES];
-static int recurse_submodules = RECURSE_SUBMODULES_DEFAULT;
 
 static int list_tree(unsigned char *sha1)
 {
@@ -99,23 +98,6 @@ static int debug_merge(const struct cache_entry * const *stages,
 	return 0;
 }
 
-static int option_parse_recurse_submodules(const struct option *opt,
-					   const char *arg, int unset)
-{
-	if (unset) {
-		recurse_submodules = RECURSE_SUBMODULES_OFF;
-		return 0;
-	}
-	if (arg)
-		recurse_submodules =
-			parse_update_recurse_submodules_arg(opt->long_name,
-							    arg);
-	else
-		recurse_submodules = RECURSE_SUBMODULES_ON;
-
-	return 0;
-}
-
 static struct lock_file lock_file;
 
 int cmd_read_tree(int argc, const char **argv, const char *unused_prefix)
@@ -159,7 +141,7 @@ int cmd_read_tree(int argc, const char **argv, const char *unused_prefix)
 			 N_("debug unpack-trees")),
 		{ OPTION_CALLBACK, 0, "recurse-submodules", NULL,
 			    "checkout", "control recursive updating of submodules",
-			    PARSE_OPT_OPTARG, option_parse_recurse_submodules },
+			    PARSE_OPT_OPTARG, option_parse_recurse_submodules_worktree_updater },
 		OPT_END()
 	};
 
@@ -173,13 +155,9 @@ int cmd_read_tree(int argc, const char **argv, const char *unused_prefix)
 	argc = parse_options(argc, argv, unused_prefix, read_tree_options,
 			     read_tree_usage, 0);
 
-	hold_locked_index(&lock_file, LOCK_DIE_ON_ERROR);
+	load_submodule_cache();
 
-	if (recurse_submodules != RECURSE_SUBMODULES_DEFAULT) {
-		gitmodules_config();
-		git_config(submodule_config, NULL);
-		set_config_update_recurse_submodules(RECURSE_SUBMODULES_ON);
-	}
+	hold_locked_index(&lock_file, LOCK_DIE_ON_ERROR);
 
 	prefix_set = opts.prefix ? 1 : 0;
 	if (1 < opts.merge + opts.reset + prefix_set)
diff --git a/builtin/reset.c b/builtin/reset.c
index 1e5f85b1fb..6f89dc5494 100644
--- a/builtin/reset.c
+++ b/builtin/reset.c
@@ -24,25 +24,6 @@
 #include "submodule.h"
 #include "submodule-config.h"
 
-static int recurse_submodules = RECURSE_SUBMODULES_DEFAULT;
-
-static int option_parse_recurse_submodules(const struct option *opt,
-					   const char *arg, int unset)
-{
-	if (unset) {
-		recurse_submodules = RECURSE_SUBMODULES_OFF;
-		return 0;
-	}
-	if (arg)
-		recurse_submodules =
-			parse_update_recurse_submodules_arg(opt->long_name,
-							    arg);
-	else
-		recurse_submodules = RECURSE_SUBMODULES_ON;
-
-	return 0;
-}
-
 static const char * const git_reset_usage[] = {
 	N_("git reset [--mixed | --soft | --hard | --merge | --keep] [-q] [<commit>]"),
 	N_("git reset [-q] [<tree-ish>] [--] <paths>..."),
@@ -306,7 +287,7 @@ int cmd_reset(int argc, const char **argv, const char *prefix)
 				N_("reset HEAD but keep local changes"), KEEP),
 		{ OPTION_CALLBACK, 0, "recurse-submodules", NULL,
 			    "reset", "control recursive updating of submodules",
-			    PARSE_OPT_OPTARG, option_parse_recurse_submodules },
+			    PARSE_OPT_OPTARG, option_parse_recurse_submodules_worktree_updater },
 		OPT_BOOL('p', "patch", &patch_mode, N_("select hunks interactively")),
 		OPT_BOOL('N', "intent-to-add", &intent_to_add,
 				N_("record only the fact that removed paths will be added later")),
@@ -319,11 +300,7 @@ int cmd_reset(int argc, const char **argv, const char *prefix)
 						PARSE_OPT_KEEP_DASHDASH);
 	parse_args(&pathspec, argv, prefix, patch_mode, &rev);
 
-	if (recurse_submodules != RECURSE_SUBMODULES_DEFAULT) {
-		gitmodules_config();
-		git_config(submodule_config, NULL);
-		set_config_update_recurse_submodules(RECURSE_SUBMODULES_ON);
-	}
+	load_submodule_cache();
 
 	unborn = !strcmp(rev, "HEAD") && get_sha1("HEAD", oid.hash);
 	if (unborn) {
diff --git a/submodule.c b/submodule.c
index 54825100b2..c9e764b519 100644
--- a/submodule.c
+++ b/submodule.c
@@ -18,7 +18,7 @@
 #include "worktree.h"
 
 static int config_fetch_recurse_submodules = RECURSE_SUBMODULES_ON_DEMAND;
-static int config_update_recurse_submodules = RECURSE_SUBMODULES_DEFAULT;
+static int config_update_recurse_submodules = RECURSE_SUBMODULES_OFF;
 static int parallel_jobs = 1;
 static struct string_list changed_submodule_paths = STRING_LIST_INIT_DUP;
 static int initialized_fetch_ref_tips;
@@ -169,6 +169,32 @@ int submodule_config(const char *var, const char *value, void *cb)
 	return 0;
 }
 
+int option_parse_recurse_submodules_worktree_updater(const struct option *opt,
+						     const char *arg, int unset)
+{
+	if (unset) {
+		config_update_recurse_submodules = RECURSE_SUBMODULES_OFF;
+		return 0;
+	}
+	if (arg)
+		config_update_recurse_submodules =
+			parse_update_recurse_submodules_arg(opt->long_name,
+							    arg);
+	else
+		config_update_recurse_submodules = RECURSE_SUBMODULES_ON;
+
+	return 0;
+}
+
+void load_submodule_cache(void)
+{
+	if (config_update_recurse_submodules == RECURSE_SUBMODULES_OFF)
+		return;
+
+	gitmodules_config();
+	git_config(submodule_config, NULL);
+}
+
 void gitmodules_config(void)
 {
 	const char *work_tree = get_git_work_tree();
@@ -596,11 +622,6 @@ void set_config_fetch_recurse_submodules(int value)
 	config_fetch_recurse_submodules = value;
 }
 
-void set_config_update_recurse_submodules(int value)
-{
-	config_update_recurse_submodules = value;
-}
-
 int should_update_submodules(void)
 {
 	return config_update_recurse_submodules == RECURSE_SUBMODULES_ON;
diff --git a/submodule.h b/submodule.h
index 1277480add..b13f120f76 100644
--- a/submodule.h
+++ b/submodule.h
@@ -39,6 +39,11 @@ extern void stage_updated_gitmodules(void);
 extern void set_diffopt_flags_from_submodule_config(struct diff_options *,
 		const char *path);
 extern int submodule_config(const char *var, const char *value, void *cb);
+
+struct option;
+int option_parse_recurse_submodules_worktree_updater(const struct option *opt,
+						     const char *arg, int unset);
+void load_submodule_cache(void);
 extern void gitmodules_config(void);
 extern void gitmodules_config_sha1(const unsigned char *commit_sha1);
 extern int is_submodule_initialized(const char *path);
@@ -65,7 +70,6 @@ extern void show_submodule_inline_diff(FILE *f, const char *path,
 		const char *del, const char *add, const char *reset,
 		const struct diff_options *opt);
 extern void set_config_fetch_recurse_submodules(int value);
-extern void set_config_update_recurse_submodules(int value);
 /* Check if we want to update any submodule.*/
 extern int should_update_submodules(void);
 /*