git/t/t5329-pack-objects-cruft.sh
Taylor Blau b757353676 builtin/pack-objects.c: --cruft without expiration
Teach `pack-objects` how to generate a cruft pack when no objects are
dropped (i.e., `--cruft-expiration=never`). Later patches will teach
`pack-objects` how to generate a cruft pack that prunes objects.

When generating a cruft pack which does not prune objects, we want to
collect all unreachable objects into a single pack (noting and updating
their mtimes as we accumulate them). Ordinary use will pass the result
of a `git repack -A` as a kept pack, so when this patch says "kept
pack", readers should think "reachable objects".

Generating a non-expiring cruft packs works as follows:

  - Callers provide a list of every pack they know about, and indicate
    which packs are about to be removed.

  - All packs which are going to be removed (we'll call these the
    redundant ones) are marked as kept in-core.

    Any packs the caller did not mention (but are known to the
    `pack-objects` process) are also marked as kept in-core. Packs not
    mentioned by the caller are assumed to be unknown to them, i.e.,
    they entered the repository after the caller decided which packs
    should be kept and which should be discarded.

    Since we do not want to include objects in these "unknown" packs
    (because we don't know which of their objects are or aren't
    reachable), these are also marked as kept in-core.

  - Then, we enumerate all objects in the repository, and add them to
    our packing list if they do not appear in an in-core kept pack.

This results in a new cruft pack which contains all known objects that
aren't included in the kept packs. When the kept pack is the result of
`git repack -A`, the resulting pack contains all unreachable objects.

Signed-off-by: Taylor Blau <me@ttaylorr.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2022-05-26 15:48:26 -07:00

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#!/bin/sh
test_description='cruft pack related pack-objects tests'
. ./test-lib.sh
objdir=.git/objects
packdir=$objdir/pack
basic_cruft_pack_tests () {
expire="$1"
test_expect_success "unreachable loose objects are packed (expire $expire)" '
git init repo &&
test_when_finished "rm -fr repo" &&
(
cd repo &&
test_commit base &&
git repack -Ad &&
test_commit loose &&
test-tool chmtime +2000 "$objdir/$(test_oid_to_path \
$(git rev-parse loose:loose.t))" &&
test-tool chmtime +1000 "$objdir/$(test_oid_to_path \
$(git rev-parse loose^{tree}))" &&
(
git rev-list --objects --no-object-names base..loose |
while read oid
do
path="$objdir/$(test_oid_to_path "$oid")" &&
printf "%s %d\n" "$oid" "$(test-tool chmtime --get "$path")"
done |
sort -k1
) >expect &&
keep="$(basename "$(ls $packdir/pack-*.pack)")" &&
cruft="$(echo $keep | git pack-objects --cruft \
--cruft-expiration="$expire" $packdir/pack)" &&
test-tool pack-mtimes "pack-$cruft.mtimes" >actual &&
test_cmp expect actual
)
'
test_expect_success "unreachable packed objects are packed (expire $expire)" '
git init repo &&
test_when_finished "rm -fr repo" &&
(
cd repo &&
test_commit packed &&
git repack -Ad &&
test_commit other &&
git rev-list --objects --no-object-names packed.. >objects &&
keep="$(basename "$(ls $packdir/pack-*.pack)")" &&
other="$(git pack-objects --delta-base-offset \
$packdir/pack <objects)" &&
git prune-packed &&
test-tool chmtime --get -100 "$packdir/pack-$other.pack" >expect &&
cruft="$(git pack-objects --cruft --cruft-expiration="$expire" $packdir/pack <<-EOF
$keep
-pack-$other.pack
EOF
)" &&
test-tool pack-mtimes "pack-$cruft.mtimes" >actual.raw &&
cut -d" " -f2 <actual.raw | sort -u >actual &&
test_cmp expect actual
)
'
test_expect_success "unreachable cruft objects are repacked (expire $expire)" '
git init repo &&
test_when_finished "rm -fr repo" &&
(
cd repo &&
test_commit packed &&
git repack -Ad &&
test_commit other &&
git rev-list --objects --no-object-names packed.. >objects &&
keep="$(basename "$(ls $packdir/pack-*.pack)")" &&
cruft_a="$(echo $keep | git pack-objects --cruft --cruft-expiration="$expire" $packdir/pack)" &&
git prune-packed &&
cruft_b="$(git pack-objects --cruft --cruft-expiration="$expire" $packdir/pack <<-EOF
$keep
-pack-$cruft_a.pack
EOF
)" &&
test-tool pack-mtimes "pack-$cruft_a.mtimes" >expect.raw &&
test-tool pack-mtimes "pack-$cruft_b.mtimes" >actual.raw &&
sort <expect.raw >expect &&
sort <actual.raw >actual &&
test_cmp expect actual
)
'
test_expect_success "multiple cruft packs (expire $expire)" '
git init repo &&
test_when_finished "rm -fr repo" &&
(
cd repo &&
test_commit reachable &&
git repack -Ad &&
keep="$(basename "$(ls $packdir/pack-*.pack)")" &&
test_commit cruft &&
loose="$objdir/$(test_oid_to_path $(git rev-parse cruft))" &&
# generate three copies of the cruft object in different
# cruft packs, each with a unique mtime:
# - one expired (1000 seconds ago)
# - two non-expired (one 1000 seconds in the future,
# one 1500 seconds in the future)
test-tool chmtime =-1000 "$loose" &&
git pack-objects --cruft $packdir/pack-A <<-EOF &&
$keep
EOF
test-tool chmtime =+1000 "$loose" &&
git pack-objects --cruft $packdir/pack-B <<-EOF &&
$keep
-$(basename $(ls $packdir/pack-A-*.pack))
EOF
test-tool chmtime =+1500 "$loose" &&
git pack-objects --cruft $packdir/pack-C <<-EOF &&
$keep
-$(basename $(ls $packdir/pack-A-*.pack))
-$(basename $(ls $packdir/pack-B-*.pack))
EOF
# ensure the resulting cruft pack takes the most recent
# mtime among all copies
cruft="$(git pack-objects --cruft \
--cruft-expiration="$expire" \
$packdir/pack <<-EOF
$keep
-$(basename $(ls $packdir/pack-A-*.pack))
-$(basename $(ls $packdir/pack-B-*.pack))
-$(basename $(ls $packdir/pack-C-*.pack))
EOF
)" &&
test-tool pack-mtimes "$(basename $(ls $packdir/pack-C-*.mtimes))" >expect.raw &&
test-tool pack-mtimes "pack-$cruft.mtimes" >actual.raw &&
sort expect.raw >expect &&
sort actual.raw >actual &&
test_cmp expect actual
)
'
test_expect_success "cruft packs tolerate missing trees (expire $expire)" '
git init repo &&
test_when_finished "rm -fr repo" &&
(
cd repo &&
test_commit reachable &&
test_commit cruft &&
tree="$(git rev-parse cruft^{tree})" &&
git reset --hard reachable &&
git tag -d cruft &&
git reflog expire --all --expire=all &&
# remove the unreachable tree, but leave the commit
# which has it as its root tree intact
rm -fr "$objdir/$(test_oid_to_path "$tree")" &&
git repack -Ad &&
basename $(ls $packdir/pack-*.pack) >in &&
git pack-objects --cruft --cruft-expiration="$expire" \
$packdir/pack <in
)
'
test_expect_success "cruft packs tolerate missing blobs (expire $expire)" '
git init repo &&
test_when_finished "rm -fr repo" &&
(
cd repo &&
test_commit reachable &&
test_commit cruft &&
blob="$(git rev-parse cruft:cruft.t)" &&
git reset --hard reachable &&
git tag -d cruft &&
git reflog expire --all --expire=all &&
# remove the unreachable blob, but leave the commit (and
# the root tree of that commit) intact
rm -fr "$objdir/$(test_oid_to_path "$blob")" &&
git repack -Ad &&
basename $(ls $packdir/pack-*.pack) >in &&
git pack-objects --cruft --cruft-expiration="$expire" \
$packdir/pack <in
)
'
}
basic_cruft_pack_tests never
test_done