t3011: demonstrate directory traversal failures

Add several tests demonstrating directory traversal failures of various
sorts in dir.c (and one similar looking test that turns out to be a
git_fnmatch bug).  A lot of these tests look like near duplicates of
each other, but an optimization path in dir.c to pre-descend into a
common prefix and the specialized treatment of trailing slashes in dir.c
mean the tiny differences are sometimes important and potentially cause
different codepaths to be explored.

Of the 7 failing tests, 2 are new to git-2.24.0 (tweaked by side effects
of the en/clean-nested-with-ignored-topic); the other 5 also failed
under git-2.23.0 and earlier.

Signed-off-by: Elijah Newren <newren@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

t/t3011-common-prefixes-and-directory-traversal.sh

@@ -0,0 +1,209 @@
+#!/bin/sh
+
+test_description='directory traversal handling, especially with common prefixes'
+
+. ./test-lib.sh
+
+test_expect_success 'setup' '
+	test_commit hello &&
+
+	>empty &&
+	mkdir untracked_dir &&
+	>untracked_dir/empty &&
+	git init untracked_repo &&
+	>untracked_repo/empty &&
+
+	cat <<-EOF >.gitignore &&
+	ignored
+	an_ignored_dir/
+	EOF
+	mkdir an_ignored_dir &&
+	mkdir an_untracked_dir &&
+	>an_ignored_dir/ignored &&
+	>an_ignored_dir/untracked &&
+	>an_untracked_dir/ignored &&
+	>an_untracked_dir/untracked
+'
+
+test_expect_success 'git ls-files -o shows the right entries' '
+	cat <<-EOF >expect &&
+	.gitignore
+	actual
+	an_ignored_dir/ignored
+	an_ignored_dir/untracked
+	an_untracked_dir/ignored
+	an_untracked_dir/untracked
+	empty
+	expect
+	untracked_dir/empty
+	untracked_repo/
+	EOF
+	git ls-files -o >actual &&
+	test_cmp expect actual
+'
+
+test_expect_success 'git ls-files -o --exclude-standard shows the right entries' '
+	cat <<-EOF >expect &&
+	.gitignore
+	actual
+	an_untracked_dir/untracked
+	empty
+	expect
+	untracked_dir/empty
+	untracked_repo/
+	EOF
+	git ls-files -o --exclude-standard >actual &&
+	test_cmp expect actual
+'
+
+test_expect_success 'git ls-files -o untracked_dir recurses' '
+	echo untracked_dir/empty >expect &&
+	git ls-files -o untracked_dir >actual &&
+	test_cmp expect actual
+'
+
+test_expect_success 'git ls-files -o untracked_dir/ recurses' '
+	echo untracked_dir/empty >expect &&
+	git ls-files -o untracked_dir/ >actual &&
+	test_cmp expect actual
+'
+
+test_expect_success 'git ls-files -o --directory untracked_dir does not recurse' '
+	echo untracked_dir/ >expect &&
+	git ls-files -o --directory untracked_dir >actual &&
+	test_cmp expect actual
+'
+
+test_expect_failure 'git ls-files -o --directory untracked_dir/ does not recurse' '
+	echo untracked_dir/ >expect &&
+	git ls-files -o --directory untracked_dir/ >actual &&
+	test_cmp expect actual
+'
+
+test_expect_success 'git ls-files -o untracked_repo does not recurse' '
+	echo untracked_repo/ >expect &&
+	git ls-files -o untracked_repo >actual &&
+	test_cmp expect actual
+'
+
+test_expect_failure 'git ls-files -o untracked_repo/ does not recurse' '
+	echo untracked_repo/ >expect &&
+	git ls-files -o untracked_repo/ >actual &&
+	test_cmp expect actual
+'
+
+test_expect_failure 'git ls-files -o untracked_dir untracked_repo recurses into untracked_dir only' '
+	cat <<-EOF >expect &&
+	untracked_dir/empty
+	untracked_repo/
+	EOF
+	git ls-files -o untracked_dir untracked_repo >actual &&
+	test_cmp expect actual
+'
+
+test_expect_success 'git ls-files -o untracked_dir/ untracked_repo/ recurses into untracked_dir only' '
+	cat <<-EOF >expect &&
+	untracked_dir/empty
+	untracked_repo/
+	EOF
+	git ls-files -o untracked_dir/ untracked_repo/ >actual &&
+	test_cmp expect actual
+'
+
+test_expect_failure 'git ls-files -o --directory untracked_dir untracked_repo does not recurse' '
+	cat <<-EOF >expect &&
+	untracked_dir/
+	untracked_repo/
+	EOF
+	git ls-files -o --directory untracked_dir untracked_repo >actual &&
+	test_cmp expect actual
+'
+
+test_expect_success 'git ls-files -o --directory untracked_dir/ untracked_repo/ does not recurse' '
+	cat <<-EOF >expect &&
+	untracked_dir/
+	untracked_repo/
+	EOF
+	git ls-files -o --directory untracked_dir/ untracked_repo/ >actual &&
+	test_cmp expect actual
+'
+
+test_expect_success 'git ls-files -o .git shows nothing' '
+	git ls-files -o .git >actual &&
+	test_must_be_empty actual
+'
+
+test_expect_failure 'git ls-files -o .git/ shows nothing' '
+	git ls-files -o .git/ >actual &&
+	test_must_be_empty actual
+'
+
+test_expect_success FUNNYNAMES 'git ls-files -o untracked_* recurses appropriately' '
+	mkdir "untracked_*" &&
+	>"untracked_*/empty" &&
+
+	cat <<-EOF >expect &&
+	untracked_*/empty
+	untracked_dir/empty
+	untracked_repo/
+	EOF
+	git ls-files -o "untracked_*" >actual &&
+	test_cmp expect actual
+'
+
+# It turns out fill_directory returns the right paths, but ls-files' post-call
+# filtering in show_dir_entry() via calling dir_path_match() which ends up
+# in git_fnmatch() has logic for PATHSPEC_ONESTAR that assumes the pathspec
+# must match the full path; it doesn't check it for matching a leading
+# directory.
+test_expect_failure FUNNYNAMES 'git ls-files -o untracked_*/ recurses appropriately' '
+	cat <<-EOF >expect &&
+	untracked_*/empty
+	untracked_dir/empty
+	untracked_repo/
+	EOF
+	git ls-files -o "untracked_*/" >actual &&
+	test_cmp expect actual
+'
+
+test_expect_success FUNNYNAMES 'git ls-files -o --directory untracked_* does not recurse' '
+	cat <<-EOF >expect &&
+	untracked_*/
+	untracked_dir/
+	untracked_repo/
+	EOF
+	git ls-files -o --directory "untracked_*" >actual &&
+	test_cmp expect actual
+'
+
+test_expect_success FUNNYNAMES 'git ls-files -o --directory untracked_*/ does not recurse' '
+	cat <<-EOF >expect &&
+	untracked_*/
+	untracked_dir/
+	untracked_repo/
+	EOF
+	git ls-files -o --directory "untracked_*/" >actual &&
+	test_cmp expect actual
+'
+
+test_expect_success 'git ls-files -o consistent between one or two dirs' '
+	git ls-files -o --exclude-standard an_ignored_dir/ an_untracked_dir/ >tmp &&
+	! grep ^an_ignored_dir/ tmp >expect &&
+	git ls-files -o --exclude-standard an_ignored_dir/ >actual &&
+	test_cmp expect actual
+'
+
+# ls-files doesn't have a way to request showing both untracked and ignored
+# files at the same time, so use `git status --ignored`
+test_expect_failure 'git status --ignored shows same files under dir with or without pathspec' '
+	cat <<-EOF >expect &&
+	?? an_untracked_dir/
+	!! an_untracked_dir/ignored
+	EOF
+	git status --porcelain --ignored >output &&
+	grep an_untracked_dir output >expect &&
+	git status --porcelain --ignored an_untracked_dir/ >actual &&
+	test_cmp expect actual
+'
+
+test_done