setup: set startup_info->have_repository more reliably

When setup_git_directory() is called, we set a flag in
startup_info to indicate we have a repository. But there are
a few other mechanisms by which we might set up a repo:

  1. When creating a new repository via init_db(), we
     transition from no-repo to being in a repo. We should
     tweak this flag at that moment.

  2. In enter_repo(), a stricter form of
     setup_git_directory() used by server-side programs, we
     check the repository format config. After doing so, we
     know we're in a repository, and can set the flag.

With these changes, library code can now reliably tell
whether we are in a repository and act accordingly. We'll
leave the "prefix" field as NULL, which is what happens when
setup_git_directory() finds there is no prefix.

Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

builtin/init-db.c

@@ -322,6 +322,7 @@ int set_git_dir_init(const char *git_dir, const char *real_git_dir,
 		set_git_dir(real_path(git_dir));
 		git_link = NULL;
 	}
+	startup_info->have_repository = 1;
 	return 0;
 }
 

setup.c

@@ -986,7 +986,9 @@ int check_repository_format_version(const char *var, const char *value, void *cb
 
 int check_repository_format(void)
 {
-	return check_repository_format_gently(get_git_dir(), NULL);
+	check_repository_format_gently(get_git_dir(), NULL);
+	startup_info->have_repository = 1;
+	return 0;
 }
 
 /*