git/t/t3000-ls-files-others.sh
Jeff King a2d5156c2b resolve_gitlink_ref: ignore non-repository paths
When we want to look up a submodule ref, we use
get_ref_cache(path) to find or auto-create its ref cache.
But if we feed a path that isn't actually a git repository,
we blindly create the ref cache, and then may die deeper in
the code when we try to access it. This is a problem because
many callers speculatively feed us a path that looks vaguely
like a repository, and expect us to tell them when it is
not.

This patch teaches resolve_gitlink_ref to reject
non-repository paths without creating a ref_cache. This
avoids the die(), and also performs better if you have a
large number of these faux-submodule directories (because
the ref_cache lookup is linear, under the assumption that
there won't be a large number of submodules).

To accomplish this, we also break get_ref_cache into two
pieces: the lookup and auto-creation (the latter is lumped
into create_ref_cache). This lets us first cheaply ask our
cache "is it a submodule we know about?" If so, we can avoid
repeating our filesystem lookup. So lookups of real
submodules are not penalized; they examine the submodule's
.git directory only once.

The test in t3000 demonstrates a case where this improves
correctness (we used to just die). The new perf case in
p7300 shows off the speed improvement in an admittedly
pathological repository:

Test                  HEAD^               HEAD
----------------------------------------------------------------
7300.4: ls-files -o   66.97(66.15+0.87)   0.33(0.08+0.24) -99.5%

Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2016-01-25 11:42:13 -08:00

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#!/bin/sh
#
# Copyright (c) 2005 Junio C Hamano
#
test_description='git ls-files test (--others should pick up symlinks).
This test runs git ls-files --others with the following on the
filesystem.
path0 - a file
path1 - a symlink
path2/file2 - a file in a directory
path3-junk - a file to confuse things
path3/file3 - a file in a directory
path4 - an empty directory
'
. ./test-lib.sh
test_expect_success 'setup ' '
date >path0 &&
if test_have_prereq SYMLINKS
then
ln -s xyzzy path1
else
date >path1
fi &&
mkdir path2 path3 path4 &&
date >path2/file2 &&
date >path2-junk &&
date >path3/file3 &&
date >path3-junk &&
git update-index --add path3-junk path3/file3
'
test_expect_success 'setup: expected output' '
cat >expected1 <<-\EOF &&
expected1
expected2
expected3
output
path0
path1
path2-junk
path2/file2
EOF
sed -e "s|path2/file2|path2/|" <expected1 >expected2 &&
cp expected2 expected3 &&
echo path4/ >>expected2
'
test_expect_success 'ls-files --others' '
git ls-files --others >output &&
test_cmp expected1 output
'
test_expect_success 'ls-files --others --directory' '
git ls-files --others --directory >output &&
test_cmp expected2 output
'
test_expect_success '--no-empty-directory hides empty directory' '
git ls-files --others --directory --no-empty-directory >output &&
test_cmp expected3 output
'
test_expect_success 'ls-files --others handles non-submodule .git' '
mkdir not-a-submodule &&
echo foo >not-a-submodule/.git &&
git ls-files -o >output &&
test_cmp expected1 output
'
test_expect_success SYMLINKS 'ls-files --others with symlinked submodule' '
git init super &&
git init sub &&
(
cd sub &&
>a &&
git add a &&
git commit -m sub &&
git pack-refs --all
) &&
(
cd super &&
"$SHELL_PATH" "$TEST_DIRECTORY/../contrib/workdir/git-new-workdir" ../sub sub
git ls-files --others --exclude-standard >../actual
) &&
echo sub/ >expect &&
test_cmp expect actual
'
test_done