There's two callsites which assemble global config paths, once in the
config loading code and once in the git-config(1) builtin. We're about
to implement a way to override global config paths via an environment
variable which would require us to adjust both sites.

Unify both code paths into a single `git_global_config()` function which
returns both paths for `~/.gitconfig` and the XDG config file. This will
make the subsequent patch which introduces the new envvar easier to
implement.

No functional changes are expected from this patch.

Signed-off-by: Patrick Steinhardt <ps@pks.im>
---
 builtin/config.c |  6 ++----
 config.c         | 20 ++++++++++++++++----
 config.h         |  1 +
 3 files changed, 19 insertions(+), 8 deletions(-)

diff --git a/builtin/config.c b/builtin/config.c
index 02ed0b3fe7..604a0973a5 100644
--- a/builtin/config.c
+++ b/builtin/config.c
@@ -671,9 +671,9 @@ int cmd_config(int argc, const char **argv, const char *prefix)
 	}
 
 	if (use_global_config) {
-		char *user_config = expand_user_path("~/.gitconfig", 0);
-		char *xdg_config = xdg_config_home("config");
+		const char *user_config, *xdg_config;
 
+		git_global_config(&user_config, &xdg_config);
 		if (!user_config)
 			/*
 			 * It is unknown if HOME/.gitconfig exists, so
@@ -688,10 +688,8 @@ int cmd_config(int argc, const char **argv, const char *prefix)
 		if (access_or_warn(user_config, R_OK, 0) &&
 		    xdg_config && !access_or_warn(xdg_config, R_OK, 0)) {
 			given_config_source.file = xdg_config;
-			free(user_config);
 		} else {
 			given_config_source.file = user_config;
-			free(xdg_config);
 		}
 	}
 	else if (use_system_config) {
diff --git a/config.c b/config.c
index c552ab4ad9..6af0244085 100644
--- a/config.c
+++ b/config.c
@@ -1852,6 +1852,19 @@ const char *git_system_config(void)
 	return system_wide;
 }
 
+void git_global_config(const char **user, const char **xdg)
+{
+	static const char *user_config, *xdg_config;
+
+	if (!user_config) {
+		user_config = expand_user_path("~/.gitconfig", 0);
+		xdg_config = xdg_config_home("config");
+	}
+
+	*user = user_config;
+	*xdg = xdg_config;
+}
+
 /*
  * Parse environment variable 'k' as a boolean (in various
  * possible spellings); if missing, use the default value 'def'.
@@ -1883,9 +1896,8 @@ static int do_git_config_sequence(const struct config_options *opts,
 				  config_fn_t fn, void *data)
 {
 	int ret = 0;
-	char *xdg_config = xdg_config_home("config");
-	char *user_config = expand_user_path("~/.gitconfig", 0);
 	char *repo_config;
+	const char *user_config, *xdg_config;
 	enum config_scope prev_parsing_scope = current_parsing_scope;
 
 	if (opts->commondir)
@@ -1903,6 +1915,8 @@ static int do_git_config_sequence(const struct config_options *opts,
 					    data);
 
 	current_parsing_scope = CONFIG_SCOPE_GLOBAL;
+	git_global_config(&user_config, &xdg_config);
+
 	if (xdg_config && !access_or_die(xdg_config, R_OK, ACCESS_EACCES_OK))
 		ret += git_config_from_file(fn, xdg_config, data);
 
@@ -1927,8 +1941,6 @@ static int do_git_config_sequence(const struct config_options *opts,
 		die(_("unable to parse command-line config"));
 
 	current_parsing_scope = prev_parsing_scope;
-	free(xdg_config);
-	free(user_config);
 	free(repo_config);
 	return ret;
 }
diff --git a/config.h b/config.h
index 8e8376ae19..53a782e0f5 100644
--- a/config.h
+++ b/config.h
@@ -327,6 +327,7 @@ int config_error_nonbool(const char *);
 #endif
 
 const char *git_system_config(void);
+void git_global_config(const char **user, const char **xdg);
 
 int git_config_parse_parameter(const char *, config_fn_t fn, void *data);
 
-- 
2.31.1