[PATCH 1/5] grep: illustrate bug when recursing with relative pathspec

[Brandon Williams <bmwill@google.com>]

When using the --recurse-submodules flag with a relative pathspec which
includes "..", an error is produced inside the child process spawned for
a submodule.  When creating the pathspec struct in the child, the ".."
is interpreted to mean "go up a directory" which causes an error stating
that the path ".." is outside of the repository.

While it is true that ".." is outside the scope of the submodule, it is
confusing to a user who originally invoked the command where ".." was
indeed still inside the scope of the superproject.  Since the child
process luanched for the submodule has some context that it is operating
underneath a superproject, this error could be avoided.

Signed-off-by: Brandon Williams <bmwill@google.com>
---
 t/t7814-grep-recurse-submodules.sh | 42 ++++++++++++++++++++++++++++++++++++++
 1 file changed, 42 insertions(+)

diff --git a/t/t7814-grep-recurse-submodules.sh b/t/t7814-grep-recurse-submodules.sh
index 67247a01d..418ba68fe 100755
--- a/t/t7814-grep-recurse-submodules.sh
+++ b/t/t7814-grep-recurse-submodules.sh
@@ -227,6 +227,48 @@ test_expect_success 'grep history with moved submoules' '
 	test_cmp expect actual
 '
 
+test_expect_failure 'grep using relative path' '
+	test_when_finished "rm -rf parent sub" &&
+	git init sub &&
+	echo "foobar" >sub/file &&
+	git -C sub add file &&
+	git -C sub commit -m "add file" &&
+
+	git init parent &&
+	echo "foobar" >parent/file &&
+	git -C parent add file &&
+	mkdir parent/src &&
+	echo "foobar" >parent/src/file2 &&
+	git -C parent add src/file2 &&
+	git -C parent submodule add ../sub &&
+	git -C parent commit -m "add files and submodule" &&
+
+	# From top works
+	cat >expect <<-\EOF &&
+	file:foobar
+	src/file2:foobar
+	sub/file:foobar
+	EOF
+	git -C parent grep --recurse-submodules -e "foobar" >actual &&
+	test_cmp expect actual &&
+
+	# Relative path to top errors out
+	cat >expect <<-\EOF &&
+	../file:foobar
+	file2:foobar
+	../sub/file:foobar
+	EOF
+	git -C parent/src grep --recurse-submodules -e "foobar" -- .. >actual &&
+	test_cmp expect actual &&
+
+	# Relative path to submodule errors out
+	cat >expect <<-\EOF &&
+	../sub/file:foobar
+	EOF
+	git -C parent/src grep --recurse-submodules -e "foobar" -- ../sub >actual &&
+	test_cmp expect actual
+'
+
 test_incompatible_with_recurse_submodules ()
 {
 	test_expect_success "--recurse-submodules and $1 are incompatible" "
-- 
2.11.0.483.g087da7b7c-goog