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sha1-file.c: don't freshen cruft packs

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We don't bother to freshen objects stored in a cruft pack individually
by updating the `.mtimes` file. This is because we can't portably `mmap`
and write into the middle of a file (i.e., to update the mtime of just
one object). Instead, we would have to rewrite the entire `.mtimes` file
which may incur some wasted effort especially if there a lot of cruft
objects and they are freshened infrequently.

Instead, force the freshening code to avoid an optimizing write by
writing out the object loose and letting it pick up a current mtime.

This works because we prefer the mtime of the loose copy of an object
when both a loose and packed one exist (whether or not the packed copy
comes from a cruft pack or not).

This could certainly do with a test and/or be included earlier in this
series/PR, but I want to wait until after I have a chance to clean up
the overly-repetitive nature of the cruft pack tests in general.

Signed-off-by: Taylor Blau <me@ttaylorr.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
This commit is contained in:
Taylor Blau 2022-05-20 19:18:17 -04:00 committed by Junio C Hamano
parent 5b92477f89
commit a613164257
2 changed files with 27 additions and 0 deletions
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2
object-file.c
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@ -2035,6 +2035,8 @@ static int freshen_packed_object(const struct object_id *oid)
struct pack_entry e;
if (!find_pack_entry(the_repository, oid, &e))
return 0;
if (e.p->is_cruft)
return 0;
if (e.p->freshened)
return 1;
if (!freshen_file(e.p->pack_name))

25
t/t5329-pack-objects-cruft.sh
View File

@ -711,4 +711,29 @@ test_expect_success 'MIDX bitmaps tolerate reachable cruft objects' '
)
'
test_expect_success 'cruft objects are freshend via loose' '
git init repo &&
test_when_finished "rm -fr repo" &&
(
cd repo &&
echo "cruft" >contents &&
blob="$(git hash-object -w -t blob contents)" &&
loose="$objdir/$(test_oid_to_path $blob)" &&
test_commit base &&
git repack --cruft -d &&
test_path_is_missing "$loose" &&
test-tool pack-mtimes "$(basename "$(ls $packdir/pack-*.mtimes)")" >cruft &&
grep "$blob" cruft &&
# write the same object again
git hash-object -w -t blob contents &&
test_path_is_file "$loose"
)
'
test_done