1 files changed, 147 insertions, 0 deletions
diff --git a/t/t4053-diff-no-index.sh b/t/t4053-diff-no-index.sh
new file mode 100755
index 000000000000..0168946b6394
--- /dev/null
+++ b/t/t4053-diff-no-index.sh
@@ -0,0 +1,147 @@
+#!/bin/sh
+
+test_description='diff --no-index'
+
+. ./test-lib.sh
+
+test_expect_success 'setup' '
+	mkdir a &&
+	mkdir b &&
+	echo 1 >a/1 &&
+	echo 2 >a/2 &&
+	git init repo &&
+	echo 1 >repo/a &&
+	mkdir -p non/git &&
+	echo 1 >non/git/a &&
+	echo 1 >non/git/b
+'
+
+test_expect_success 'git diff --no-index directories' '
+	test_expect_code 1 git diff --no-index a b >cnt &&
+	test_line_count = 14 cnt
+'
+
+test_expect_success 'git diff --no-index relative path outside repo' '
+	(
+		cd repo &&
+		test_expect_code 0 git diff --no-index a ../non/git/a &&
+		test_expect_code 0 git diff --no-index ../non/git/a ../non/git/b
+	)
+'
+
+test_expect_success 'git diff --no-index with broken index' '
+	(
+		cd repo &&
+		echo broken >.git/index &&
+		git diff --no-index a ../non/git/a
+	)
+'
+
+test_expect_success 'git diff outside repo with broken index' '
+	(
+		cd repo &&
+		git diff ../non/git/a ../non/git/b
+	)
+'
+
+test_expect_success 'git diff --no-index executed outside repo gives correct error message' '
+	(
+		GIT_CEILING_DIRECTORIES=$TRASH_DIRECTORY/non &&
+		export GIT_CEILING_DIRECTORIES &&
+		cd non/git &&
+		test_must_fail git diff --no-index a 2>actual.err &&
+		test_i18ngrep "usage: git diff --no-index" actual.err
+	)
+'
+
+test_expect_success 'diff D F and diff F D' '
+	(
+		cd repo &&
+		echo in-repo >a &&
+		echo non-repo >../non/git/a &&
+		mkdir sub &&
+		echo sub-repo >sub/a &&
+
+		test_must_fail git diff --no-index sub/a ../non/git/a >expect &&
+		test_must_fail git diff --no-index sub/a ../non/git/ >actual &&
+		test_cmp expect actual &&
+
+		test_must_fail git diff --no-index a ../non/git/a >expect &&
+		test_must_fail git diff --no-index a ../non/git/ >actual &&
+		test_cmp expect actual &&
+
+		test_must_fail git diff --no-index ../non/git/a a >expect &&
+		test_must_fail git diff --no-index ../non/git a >actual &&
+		test_cmp expect actual
+	)
+'
+
+test_expect_success 'turning a file into a directory' '
+	(
+		cd non/git &&
+		mkdir d e e/sub &&
+		echo 1 >d/sub &&
+		echo 2 >e/sub/file &&
+		printf "D\td/sub\nA\te/sub/file\n" >expect &&
+		test_must_fail git diff --no-index --name-status d e >actual &&
+		test_cmp expect actual
+	)
+'
+
+test_expect_success 'diff from repo subdir shows real paths (explicit)' '
+	echo "diff --git a/../../non/git/a b/../../non/git/b" >expect &&
+	test_expect_code 1 \
+		git -C repo/sub \
+		diff --no-index ../../non/git/a ../../non/git/b >actual &&
+	head -n 1 <actual >actual.head &&
+	test_cmp expect actual.head
+'
+
+test_expect_success 'diff from repo subdir shows real paths (implicit)' '
+	echo "diff --git a/../../non/git/a b/../../non/git/b" >expect &&
+	test_expect_code 1 \
+		git -C repo/sub \
+		diff ../../non/git/a ../../non/git/b >actual &&
+	head -n 1 <actual >actual.head &&
+	test_cmp expect actual.head
+'
+
+test_expect_success 'diff --no-index from repo subdir respects config (explicit)' '
+	echo "diff --git ../../non/git/a ../../non/git/b" >expect &&
+	test_config -C repo diff.noprefix true &&
+	test_expect_code 1 \
+		git -C repo/sub \
+		diff --no-index ../../non/git/a ../../non/git/b >actual &&
+	head -n 1 <actual >actual.head &&
+	test_cmp expect actual.head
+'
+
+test_expect_success 'diff --no-index from repo subdir respects config (implicit)' '
+	echo "diff --git ../../non/git/a ../../non/git/b" >expect &&
+	test_config -C repo diff.noprefix true &&
+	test_expect_code 1 \
+		git -C repo/sub \
+		diff ../../non/git/a ../../non/git/b >actual &&
+	head -n 1 <actual >actual.head &&
+	test_cmp expect actual.head
+'
+
+test_expect_success 'diff --no-index from repo subdir with absolute paths' '
+	cat <<-EOF >expect &&
+	1	1	$(pwd)/non/git/{a => b}
+	EOF
+	test_expect_code 1 \
+		git -C repo/sub diff --numstat \
+		"$(pwd)/non/git/a" "$(pwd)/non/git/b" >actual &&
+	test_cmp expect actual
+'
+
+test_expect_success 'diff --no-index allows external diff' '
+	test_expect_code 1 \
+		env GIT_EXTERNAL_DIFF="echo external ;:" \
+		git diff --no-index non/git/a non/git/b >actual &&
+	echo external >expect &&
+	test_cmp expect actual
+'
+
+test_done