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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>
maint
Derrick Stolee 2020-02-21 21:47:28 +00:00 committed by Junio C Hamano
parent d0badf8797
commit 3e96c66805
2 changed files with 6 additions and 6 deletions
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10
builtin/fetch.c
View File

@ -335,6 +335,7 @@ static void find_non_local_tags(const struct ref *refs,
struct string_list_item *remote_ref_item; struct string_list_item *remote_ref_item;
const struct ref *ref; const struct ref *ref;
struct refname_hash_entry *item = NULL; struct refname_hash_entry *item = NULL;
const int quick_flags = OBJECT_INFO_QUICK | OBJECT_INFO_SKIP_FETCH_OBJECT;


refname_hash_init(&existing_refs); refname_hash_init(&existing_refs);
refname_hash_init(&remote_refs); refname_hash_init(&remote_refs);
@ -353,10 +354,9 @@ static void find_non_local_tags(const struct ref *refs,
*/ */
if (ends_with(ref->name, "^{}")) { if (ends_with(ref->name, "^{}")) {
if (item && if (item &&
!has_object_file_with_flags(&ref->old_oid, !has_object_file_with_flags(&ref->old_oid, quick_flags) &&
OBJECT_INFO_QUICK) &&
!oidset_contains(&fetch_oids, &ref->old_oid) && !oidset_contains(&fetch_oids, &ref->old_oid) &&
!has_object_file_with_flags(&item->oid, OBJECT_INFO_QUICK) && !has_object_file_with_flags(&item->oid, quick_flags) &&
!oidset_contains(&fetch_oids, &item->oid)) !oidset_contains(&fetch_oids, &item->oid))
clear_item(item); clear_item(item);
item = NULL; item = NULL;
@ -370,7 +370,7 @@ static void find_non_local_tags(const struct ref *refs,
* fetch. * fetch.
*/ */
if (item && if (item &&
!has_object_file_with_flags(&item->oid, OBJECT_INFO_QUICK) && !has_object_file_with_flags(&item->oid, quick_flags) &&
!oidset_contains(&fetch_oids, &item->oid)) !oidset_contains(&fetch_oids, &item->oid))
clear_item(item); clear_item(item);


@ -391,7 +391,7 @@ static void find_non_local_tags(const struct ref *refs,
* checked to see if it needs fetching. * checked to see if it needs fetching.
*/ */
if (item && if (item &&
!has_object_file_with_flags(&item->oid, OBJECT_INFO_QUICK) && !has_object_file_with_flags(&item->oid, quick_flags) &&
!oidset_contains(&fetch_oids, &item->oid)) !oidset_contains(&fetch_oids, &item->oid))
clear_item(item); clear_item(item);



2
t/t5616-partial-clone.sh
View File

@ -390,7 +390,7 @@ test_expect_failure 'verify fetch succeeds when asking for new tags' '
git -C tag-test -c protocol.version=2 fetch --tags origin git -C tag-test -c protocol.version=2 fetch --tags origin
' '


test_expect_failure 'verify fetch downloads only one pack when updating refs' ' test_expect_success 'verify fetch downloads only one pack when updating refs' '
git clone --filter=blob:none "file://$(pwd)/srv.bare" pack-test && git clone --filter=blob:none "file://$(pwd)/srv.bare" pack-test &&
ls pack-test/.git/objects/pack/*pack >pack-list && ls pack-test/.git/objects/pack/*pack >pack-list &&
test_line_count = 2 pack-list && test_line_count = 2 pack-list &&