From a2d5156c2b0e6dbffc216b4a673156487a2f8b65 Mon Sep 17 00:00:00 2001 From: Jeff King Date: Fri, 22 Jan 2016 17:29:30 -0500 Subject: 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 Signed-off-by: Junio C Hamano --- t/perf/p7300-clean.sh | 4 ++++ 1 file changed, 4 insertions(+) (limited to 't/perf') diff --git a/t/perf/p7300-clean.sh b/t/perf/p7300-clean.sh index ec94cdd657..7c1888a27e 100755 --- a/t/perf/p7300-clean.sh +++ b/t/perf/p7300-clean.sh @@ -28,4 +28,8 @@ test_perf 'clean many untracked sub dirs, ignore nested git' ' git clean -n -q -f -f -d 100000_sub_dirs/ ' +test_perf 'ls-files -o' ' + git ls-files -o +' + test_done -- cgit v1.2.3