From 2cfe66a8ee57fb3da18c262db8e6df95e263510b Mon Sep 17 00:00:00 2001
From: Jacob Keller <jacob.keller@gmail.com>
Date: Thu, 13 Apr 2017 10:12:24 -0700
Subject: ls-files: fix path used when recursing into submodules

Don't assume that the current working directory is the root of the
repository. Correctly generate the path for the recursing child
processes by building it from the work_tree() root instead. Otherwise if
we run ls-files using --git-dir or --work-tree it will not work
correctly as it attempts to change directory into a potentially invalid
location. Best case, it doesn't exist and we produce an error. Worst
case we cd into the wrong location and unknown behavior occurs.

Add a new test which highlights this possibility.

Signed-off-by: Jacob Keller <jacob.keller@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

diff --git a/builtin/ls-files.c b/builtin/ls-files.c
index e9b3546..a6c70db 100644
--- a/builtin/ls-files.c
+++ b/builtin/ls-files.c
@@ -203,6 +203,7 @@ static void show_gitlink(const struct cache_entry *ce)
 {
 	struct child_process cp = CHILD_PROCESS_INIT;
 	int status;
+	char *dir;
 
 	prepare_submodule_repo_env(&cp.env_array);
 	argv_array_push(&cp.env_array, GIT_DIR_ENVIRONMENT);
@@ -221,8 +222,10 @@ static void show_gitlink(const struct cache_entry *ce)
 	argv_array_pushv(&cp.args, submodule_options.argv);
 
 	cp.git_cmd = 1;
-	cp.dir = ce->name;
+	dir = mkpathdup("%s/%s", get_git_work_tree(), ce->name);
+	cp.dir = dir;
 	status = run_command(&cp);
+	free(dir);
 	if (status)
 		exit(status);
 }
diff --git a/t/t3007-ls-files-recurse-submodules.sh b/t/t3007-ls-files-recurse-submodules.sh
index c8030dd..ebb956f 100755
--- a/t/t3007-ls-files-recurse-submodules.sh
+++ b/t/t3007-ls-files-recurse-submodules.sh
@@ -82,6 +82,17 @@ test_expect_success 'ls-files recurses more than 1 level' '
 	test_cmp expect actual
 '
 
+test_expect_success 'ls-files works with GIT_DIR' '
+	cat >expect <<-\EOF &&
+	.gitmodules
+	c
+	subsub/d
+	EOF
+
+	git --git-dir=submodule/.git ls-files --recurse-submodules >actual &&
+	test_cmp expect actual
+'
+
 test_expect_success '--recurse-submodules and pathspecs setup' '
 	echo e >submodule/subsub/e.txt &&
 	git -C submodule/subsub add e.txt &&
-- 
cgit v0.10.2-6-g49f6