[PATCH 2/2] resolve_gitlink_ref: ignore non-repository paths
- From
Jeff King <peff@peff.net>
- Date
- Jan 22, 2016, 22:29 UTC
- Message-ID
- <20160122222930.GB15560@sigill.intra.peff.net>
- In-Reply-To
- <20160122222650.GA14772@sigill.intra.peff.net>
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> --- refs/files-backend.c | 46 ++++++++++++++++++++++++++++++++-------------- t/perf/p7300-clean.sh | 4 ++++ t/t3000-ls-files-others.sh | 7 +++++++ 3 files changed, 43 insertions(+), 14 deletions(-)
diff --git a/refs/files-backend.c b/refs/files-backend.c index c648b5e..3a27f27 100644 --- a/refs/files-backend.c +++ b/refs/files-backend.c @@ -933,6 +933,10 @@ static void clear_loose_ref_cache(struct ref_cache *refs) } } +/* + * Create a new submodule ref cache and add it to the internal + * set of caches. + */ static struct ref_cache *create_ref_cache(const char *submodule) { int len; @@ -942,16 +946,12 @@ static struct ref_cache *create_ref_cache(const char *submodule) len = strlen(submodule) + 1; refs = xcalloc(1, sizeof(struct ref_cache) + len); memcpy(refs->name, submodule, len); + refs->next = submodule_ref_caches; + submodule_ref_caches = refs; return refs; } -/* - * Return a pointer to a ref_cache for the specified submodule. For - * the main repository, use submodule==NULL. The returned structure - * will be allocated and initialized but not necessarily populated; it - * should not be freed. - */ -static struct ref_cache *get_ref_cache(const char *submodule) +static struct ref_cache *lookup_ref_cache(const char *submodule) { struct ref_cache *refs; @@ -961,10 +961,20 @@ static struct ref_cache *get_ref_cache(const char *submodule) for (refs = submodule_ref_caches; refs; refs = refs->next) if (!strcmp(submodule, refs->name)) return refs; + return NULL; +} - refs = create_ref_cache(submodule); - refs->next = submodule_ref_caches; - submodule_ref_caches = refs; +/* + * Return a pointer to a ref_cache for the specified submodule. For + * the main repository, use submodule==NULL. The returned structure + * will be allocated and initialized but not necessarily populated; it + * should not be freed. + */ +static struct ref_cache *get_ref_cache(const char *submodule) +{ + struct ref_cache *refs = lookup_ref_cache(submodule); + if (!refs) + refs = create_ref_cache(submodule); return refs; } @@ -1336,16 +1346,24 @@ static int resolve_gitlink_ref_recursive(struct ref_cache *refs, int resolve_gitlink_ref(const char *path, const char *refname, unsigned char *sha1) { int len = strlen(path), retval; - char *submodule; + struct strbuf submodule = STRBUF_INIT; struct ref_cache *refs; while (len && path[len-1] == '/') len--; if (!len) return -1; - submodule = xstrndup(path, len); - refs = get_ref_cache(submodule); - free(submodule); + + strbuf_add(&submodule, path, len); + refs = lookup_ref_cache(submodule.buf); + if (!refs) { + if (!is_nonbare_repository_dir(&submodule)) { + strbuf_release(&submodule); + return -1; + } + refs = create_ref_cache(submodule.buf); + } + strbuf_release(&submodule); retval = resolve_gitlink_ref_recursive(refs, refname, sha1, 0); return retval; diff --git a/t/perf/p7300-clean.sh b/t/perf/p7300-clean.sh index ec94cdd..7c1888a 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 diff --git a/t/t3000-ls-files-others.sh b/t/t3000-ls-files-others.sh index 88be904..c525656 100755 --- a/t/t3000-ls-files-others.sh +++ b/t/t3000-ls-files-others.sh @@ -65,6 +65,13 @@ test_expect_success '--no-empty-directory hides empty directory' ' 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 &&
-- 2.7.0.384.gae54cb4