git: pass in repo to builtin based on setup_git_directory_gently

The current code in run_builtin() passes in a repository to the builtin
based on whether cmd_struct's option flag has RUN_SETUP.

This is incorrect, however, since some builtins that only have
RUN_SETUP_GENTLY can potentially take a repository.
setup_git_directory_gently() tells us whether or not a command is being
run inside of a repository.

Use the output of setup_git_directory_gently() to help determine whether
or not there is a repository to pass to the builtin. If not, then we
just pass NULL.

As part of this patch, we need to modify add to check for a NULL repo
before calling repo_git_config(), since add -h can be run outside of a
repository.

Signed-off-by: John Cai <[email protected]>

builtin/add.c

@@ -385,7 +385,8 @@ int cmd_add(int argc,
 	char *ps_matched = NULL;
 	struct lock_file lock_file = LOCK_INIT;
 
-	repo_config(repo, add_config, NULL);
+	if (repo)
+		repo_config(repo, add_config, NULL);
 
 	argc = parse_options(argc, argv, prefix, builtin_add_options,
 			  builtin_add_usage, PARSE_OPT_KEEP_ARGV0);

git.c

@@ -444,6 +444,7 @@ static int handle_alias(int *argcp, const char ***argv)
 static int run_builtin(struct cmd_struct *p, int argc, const char **argv, struct repository *repo)
 {
 	int status, help;
+	int no_repo = 1;
 	struct stat st;
 	const char *prefix;
 	int run_setup = (p->option & (RUN_SETUP | RUN_SETUP_GENTLY));
@@ -455,9 +456,9 @@ static int run_builtin(struct cmd_struct *p, int argc, const char **argv, struct
 
 	if (run_setup & RUN_SETUP) {
 		prefix = setup_git_directory();
+		no_repo = 0;
 	} else if (run_setup & RUN_SETUP_GENTLY) {
-		int nongit_ok;
-		prefix = setup_git_directory_gently(&nongit_ok);
+		prefix = setup_git_directory_gently(&no_repo);
 	} else {
 		prefix = NULL;
 	}
@@ -480,7 +481,7 @@ static int run_builtin(struct cmd_struct *p, int argc, const char **argv, struct
 	trace2_cmd_name(p->cmd);
 
 	validate_cache_entries(repo->index);
-	status = p->fn(argc, argv, prefix, (p->option & RUN_SETUP)? repo : NULL);
+	status = p->fn(argc, argv, prefix, no_repo ? NULL : repo);
 	validate_cache_entries(repo->index);
 
 	if (status)