init-db: die on config errors when initializing empty repo

When creating an empty repository with `git init-db` we do not
check for error codes returned by `git_config_set` functions.
This may cause the user to end up with an inconsistent repository
without any indication for the user.

Fix this problem by dying early with an error message when we are
unable to write the configuration files to disk.

Signed-off-by: Patrick Steinhardt <ps@pks.im>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

builtin/init-db.c

@@ -227,7 +227,7 @@ static int create_default_files(const char *template_path)
 	/* This forces creation of new config file */
 	xsnprintf(repo_version_string, sizeof(repo_version_string),
 		  "%d", GIT_REPO_VERSION);
-	git_config_set("core.repositoryformatversion", repo_version_string);
+	git_config_set_or_die("core.repositoryformatversion", repo_version_string);
 
 	/* Check filemode trustability */
 	path = git_path_buf(&buf, "config");
@@ -241,18 +241,18 @@ static int create_default_files(const char *template_path)
 		if (filemode && !reinit && (st1.st_mode & S_IXUSR))
 			filemode = 0;
 	}
-	git_config_set("core.filemode", filemode ? "true" : "false");
+	git_config_set_or_die("core.filemode", filemode ? "true" : "false");
 
 	if (is_bare_repository())
-		git_config_set("core.bare", "true");
+		git_config_set_or_die("core.bare", "true");
 	else {
 		const char *work_tree = get_git_work_tree();
-		git_config_set("core.bare", "false");
+		git_config_set_or_die("core.bare", "false");
 		/* allow template config file to override the default */
 		if (log_all_ref_updates == -1)
-		    git_config_set("core.logallrefupdates", "true");
+			git_config_set_or_die("core.logallrefupdates", "true");
 		if (needs_work_tree_config(get_git_dir(), work_tree))
-			git_config_set("core.worktree", work_tree);
+			git_config_set_or_die("core.worktree", work_tree);
 	}
 
 	if (!reinit) {
@@ -265,12 +265,12 @@ static int create_default_files(const char *template_path)
 		    S_ISLNK(st1.st_mode))
 			unlink(path); /* good */
 		else
-			git_config_set("core.symlinks", "false");
+			git_config_set_or_die("core.symlinks", "false");
 
 		/* Check if the filesystem is case-insensitive */
 		path = git_path_buf(&buf, "CoNfIg");
 		if (!access(path, F_OK))
-			git_config_set("core.ignorecase", "true");
+			git_config_set_or_die("core.ignorecase", "true");
 		probe_utf8_pathname_composition();
 	}
 
@@ -386,8 +386,8 @@ int init_db(const char *template_dir, unsigned int flags)
 			xsnprintf(buf, sizeof(buf), "%d", OLD_PERM_EVERYBODY);
 		else
 			die("BUG: invalid value for shared_repository");
-		git_config_set("core.sharedrepository", buf);
-		git_config_set("receive.denyNonFastforwards", "true");
+		git_config_set_or_die("core.sharedrepository", buf);
+		git_config_set_or_die("receive.denyNonFastforwards", "true");
 	}
 
 	if (!(flags & INIT_DB_QUIET)) {