remote: move remote group resolution to remote.c

`get_remote_group`, `add_remote_or_group`, and the `remote_group_data`
struct are currently defined as static helpers inside builtin/fetch.c.
They implement generic remote group resolution that is not specific to
fetch — they parse `remotes.<name>` config entries and resolve a name
to either a list of group members or a single configured remote.

Move them to remote.c and declare them in remote.h so that other
builtins can use the same logic without duplication.

Useful for the next patch.

Suggested-by: Junio C Hamano <gitster@pobox.com>
Signed-off-by: Usman Akinyemi <usmanakinyemi202@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

Author: Unique-Usman

builtin/fetch.c

@@ -2138,48 +2138,6 @@ static int get_one_remote_for_fetch(struct remote *remote, void *priv)
 	return 0;
 }
 
-struct remote_group_data {
-	const char *name;
-	struct string_list *list;
-};
-
-static int get_remote_group(const char *key, const char *value,
-			    const struct config_context *ctx UNUSED,
-			    void *priv)
-{
-	struct remote_group_data *g = priv;
-
-	if (skip_prefix(key, "remotes.", &key) && !strcmp(key, g->name)) {
-		/* split list by white space */
-		while (*value) {
-			size_t wordlen = strcspn(value, " \t\n");
-
-			if (wordlen >= 1)
-				string_list_append_nodup(g->list,
-						   xstrndup(value, wordlen));
-			value += wordlen + (value[wordlen] != '\0');
-		}
-	}
-
-	return 0;
-}
-
-static int add_remote_or_group(const char *name, struct string_list *list)
-{
-	int prev_nr = list->nr;
-	struct remote_group_data g;
-	g.name = name; g.list = list;
-
-	repo_config(the_repository, get_remote_group, &g);
-	if (list->nr == prev_nr) {
-		struct remote *remote = remote_get(name);
-		if (!remote_is_configured(remote, 0))
-			return 0;
-		string_list_append(list, remote->name);
-	}
-	return 1;
-}
-
 static void add_options_to_argv(struct strvec *argv,
 				const struct fetch_config *config)
 {

remote.c

@@ -2114,6 +2114,43 @@ int get_fetch_map(const struct ref *remote_refs,
 	return 0;
 }
 
+int get_remote_group(const char *key, const char *value,
+			    const struct config_context *ctx UNUSED,
+			    void *priv)
+{
+	struct remote_group_data *g = priv;
+
+	if (skip_prefix(key, "remotes.", &key) && !strcmp(key, g->name)) {
+		/* split list by white space */
+		while (*value) {
+			size_t wordlen = strcspn(value, " \t\n");
+
+			if (wordlen >= 1)
+				string_list_append_nodup(g->list,
+						   xstrndup(value, wordlen));
+			value += wordlen + (value[wordlen] != '\0');
+		}
+	}
+
+	return 0;
+}
+
+int add_remote_or_group(const char *name, struct string_list *list)
+{
+	int prev_nr = list->nr;
+	struct remote_group_data g;
+	g.name = name; g.list = list;
+
+	repo_config(the_repository, get_remote_group, &g);
+	if (list->nr == prev_nr) {
+		struct remote *remote = remote_get(name);
+		if (!remote_is_configured(remote, 0))
+			return 0;
+		string_list_append(list, remote->name);
+	}
+	return 1;
+}
+
 int resolve_remote_symref(struct ref *ref, struct ref *list)
 {
 	if (!ref->symref)

remote.h

@@ -347,6 +347,18 @@ int branch_has_merge_config(struct branch *branch);
 
 int branch_merge_matches(struct branch *, int n, const char *);
 
+/* list of the remote in a group as configured */
+struct remote_group_data {
+	const char *name;
+	struct string_list *list;
+};
+
+int get_remote_group(const char *key, const char *value,
+                    const struct config_context *ctx,
+                    void *priv);
+
+int add_remote_or_group(const char *name, struct string_list *list);
+
 /**
  * Return the fully-qualified refname of the tracking branch for `branch`.
  * I.e., what "branch@{upstream}" would give you. Returns NULL if no