mirrors/git
0
0
Fork 0
mirror of https://github.com/git/git.git synced 2024-11-27 20:14:30 +08:00
Code Issues Packages Projects Releases Wiki Activity

commit: don't lazy-fetch commits

Browse Source 
When parsing commits, fail fast when the commit is missing or
corrupt, instead of attempting to fetch them. This is done by inlining
repo_read_object_file() and setting the flag that prevents fetching.

This is motivated by a situation in which through a bug (not necessarily
through Git), there was corruption in the object store of a partial
clone. In this particular case, the problem was exposed when "git gc"
tried to expire reflogs, which calls repo_parse_commit(), which triggers
fetches of the missing commits.

(There are other possible solutions to this problem including passing an
argument from "git gc" to "git reflog" to inhibit all lazy fetches, but
I think that this fix is at the wrong level - fixing "git reflog" means
that this particular command works fine, or so we think (it will fail if
it somehow needs to read a legitimately missing blob, say, a .gitmodules
file), but fixing repo_parse_commit() will fix a whole class of bugs.)

Signed-off-by: Jonathan Tan <jonathantanmy@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
This commit is contained in:
Jonathan Tan 2022-12-14 11:17:43 -08:00 committed by Junio C Hamano
parent 9e59b38c88
commit 7e2ad1cda2
1 changed files with 13 additions and 2 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

15
commit.c
View File

@ -508,6 +508,17 @@ int repo_parse_commit_internal(struct repository *r,
enum object_type type;
void *buffer;
unsigned long size;
struct object_info oi = {
.typep = &type,
.sizep = &size,
.contentp = &buffer,
};
/*
* Git does not support partial clones that exclude commits, so set
* OBJECT_INFO_SKIP_FETCH_OBJECT to fail fast when an object is missing.
*/
int flags = OBJECT_INFO_LOOKUP_REPLACE | OBJECT_INFO_SKIP_FETCH_OBJECT |
OBJECT_INFO_DIE_IF_CORRUPT;
int ret;
if (!item)
@ -516,8 +527,8 @@ int repo_parse_commit_internal(struct repository *r,
return 0;
if (use_commit_graph && parse_commit_in_graph(r, item))
return 0;
buffer = repo_read_object_file(r, &item->object.oid, &type, &size);
if (!buffer)
if (oid_object_info_extended(r, &item->object.oid, &oi, flags) < 0)
return quiet_on_missing ? -1 :
error("Could not read %s",
oid_to_hex(&item->object.oid));