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>

1 files changed, 11 insertions, 0 deletions

diff --git a/t/t3007-ls-files-recurse-submodules.sh b/t/t3007-ls-files-recurse-submodules.sh
index c8030dd32..ebb956fd1 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 &&