partial-clone: avoid fetching when looking for objects

When using partial clone, find_non_local_tags() in builtin/fetch.c checks each remote tag to see if its object also exists locally. There is no expectation that the object exist locally, but this function nevertheless triggers a lazy fetch if the object does not exist. This can be extremely expensive when asking for a commit, as we are completely removed from the context of the non-existent object and thus supply no "haves" in the request. 6462d5eb9a (fetch: remove fetch_if_missing=0, 2019-11-05) removed a global variable that prevented these fetches in favor of a bitflag. However, some object existence checks were not updated to use this flag. Update find_non_local_tags() to use OBJECT_INFO_SKIP_FETCH_OBJECT in addition to OBJECT_INFO_QUICK. The _QUICK option only prevents repreparing the pack-file structures. We need to be extremely careful about supplying _SKIP_FETCH_OBJECT when we expect an object to not exist due to updated refs. This resolves a broken test in t5616-partial-clone.sh. Signed-off-by: Derrick Stolee <dstolee@microsoft.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>

Derrick Stolee committed Feb 21, 2020 at 21:47 UTC 3e96c66805f17d7345eba4733bc80c6fe646b95f

2 files changed +6 -6

builtin/fetch.c

+5 -5

@@ -335,6 +335,7 @@ static void find_non_local_tags(const struct ref *refs,

335 struct string_list_item *remote_ref_item;

336 const struct ref *ref;

337 struct refname_hash_entry *item = NULL;

338 + const int quick_flags = OBJECT_INFO_QUICK | OBJECT_INFO_SKIP_FETCH_OBJECT;

339

340 refname_hash_init(&existing_refs);

341 refname_hash_init(&remote_refs);

@@ -353,10 +354,9 @@ static void find_non_local_tags(const struct ref *refs,

354 */

355 if (ends_with(ref->name, "^{}")) {

356 if (item &&

356 - !has_object_file_with_flags(&ref->old_oid,

357 - OBJECT_INFO_QUICK) &&

357 + !has_object_file_with_flags(&ref->old_oid, quick_flags) &&

358 !oidset_contains(&fetch_oids, &ref->old_oid) &&

359 - !has_object_file_with_flags(&item->oid, OBJECT_INFO_QUICK) &&

359 + !has_object_file_with_flags(&item->oid, quick_flags) &&

360 !oidset_contains(&fetch_oids, &item->oid))

361 clear_item(item);

362 item = NULL;

@@ -370,7 +370,7 @@ static void find_non_local_tags(const struct ref *refs,

370 * fetch.

371 */

372 if (item &&

373 - !has_object_file_with_flags(&item->oid, OBJECT_INFO_QUICK) &&

373 + !has_object_file_with_flags(&item->oid, quick_flags) &&

374 !oidset_contains(&fetch_oids, &item->oid))

375 clear_item(item);

376

@@ -391,7 +391,7 @@ static void find_non_local_tags(const struct ref *refs,

391 * checked to see if it needs fetching.

392 */

393 if (item &&

394 - !has_object_file_with_flags(&item->oid, OBJECT_INFO_QUICK) &&

394 + !has_object_file_with_flags(&item->oid, quick_flags) &&

395 !oidset_contains(&fetch_oids, &item->oid))

396 clear_item(item);

397

t/t5616-partial-clone.sh

+1 -1

@@ -390,7 +390,7 @@ test_expect_failure 'verify fetch succeeds when asking for new tags' '

390 git -C tag-test -c protocol.version=2 fetch --tags origin

391 '

392

393 -test_expect_failure 'verify fetch downloads only one pack when updating refs' '

393 +test_expect_success 'verify fetch downloads only one pack when updating refs' '

394 git clone --filter=blob:none "file://$(pwd)/srv.bare" pack-test &&

395 ls pack-test/.git/objects/pack/*pack >pack-list &&

396 test_line_count = 2 pack-list &&