Merge branch 'ps/config-global-override'

Replace GIT_CONFIG_NOSYSTEM mechanism to decline from reading the
system-wide configuration file with GIT_CONFIG_SYSTEM that lets
users specify from which file to read the system-wide configuration
(setting it to an empty file would essentially be the same as
setting NOSYSTEM), and introduce GIT_CONFIG_GLOBAL to override the
per-user configuration in $HOME/.gitconfig.

* ps/config-global-override:
  t1300: fix unset of GIT_CONFIG_NOSYSTEM leaking into subsequent tests
  config: allow overriding of global and system configuration
  config: unify code paths to get global config paths
  config: rename `git_etc_config()`

1 files changed, 29 insertions, 12 deletions

diff --git a/config.c b/config.c
index 870d9534de..f9c400ad30 100644
--- a/config.c
+++ b/config.c
@@ -1830,12 +1830,26 @@ static int git_config_from_blob_ref(config_fn_t fn,
 	return git_config_from_blob_oid(fn, name, &oid, data);
 }
 
-const char *git_etc_gitconfig(void)
+char *git_system_config(void)
 {
-	static const char *system_wide;
-	if (!system_wide)
-		system_wide = system_path(ETC_GITCONFIG);
-	return system_wide;
+	char *system_config = xstrdup_or_null(getenv("GIT_CONFIG_SYSTEM"));
+	if (system_config)
+		return system_config;
+	return system_path(ETC_GITCONFIG);
+}
+
+void git_global_config(char **user_out, char **xdg_out)
+{
+	char *user_config = xstrdup_or_null(getenv("GIT_CONFIG_GLOBAL"));
+	char *xdg_config = NULL;
+
+	if (!user_config) {
+		user_config = expand_user_path("~/.gitconfig", 0);
+		xdg_config = xdg_config_home("config");
+	}
+
+	*user_out = user_config;
+	*xdg_out = xdg_config;
 }
 
 /*
@@ -1869,8 +1883,9 @@ 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 *system_config = git_system_config();
+	char *xdg_config = NULL;
+	char *user_config = NULL;
 	char *repo_config;
 	enum config_scope prev_parsing_scope = current_parsing_scope;
 
@@ -1882,13 +1897,14 @@ static int do_git_config_sequence(const struct config_options *opts,
 		repo_config = NULL;
 
 	current_parsing_scope = CONFIG_SCOPE_SYSTEM;
-	if (git_config_system() && !access_or_die(git_etc_gitconfig(), R_OK,
-						  opts->system_gently ?
-						  ACCESS_EACCES_OK : 0))
-		ret += git_config_from_file(fn, git_etc_gitconfig(),
-					    data);
+	if (git_config_system() && system_config &&
+	    !access_or_die(system_config, R_OK,
+			   opts->system_gently ? ACCESS_EACCES_OK : 0))
+		ret += git_config_from_file(fn, system_config, 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);
 
@@ -1913,6 +1929,7 @@ 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(system_config);
 	free(xdg_config);
 	free(user_config);
 	free(repo_config);