git/t/t7700-repack.sh
Taylor Blau 324efc90d1 builtin/repack.c: pass --refs-snapshot when writing bitmaps
To prevent the race described in an earlier patch, generate and pass a
reference snapshot to the multi-pack bitmap code, if we are writing one
from `git repack`.

This patch is mostly limited to creating a temporary file, and then
calling for_each_ref(). Except we try to minimize duplicates, since
doing so can drastically reduce the size in network-of-forks style
repositories. In the kernel's fork network (the repository containing
all objects from the kernel and all its forks), deduplicating the
references drops the snapshot size from 934 MB to just 12 MB.

But since we're handling duplicates in this way, we have to make sure
that we preferred references (those listed in pack.preferBitmapTips)
before non-preferred ones (to avoid recording an object which is pointed
at by a preferred tip as non-preferred).

We accomplish this by doing separate passes over the references: first
visiting each prefix in pack.preferBitmapTips, and then over the rest of
the references.

Signed-off-by: Taylor Blau <me@ttaylorr.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2021-10-01 16:40:09 -07:00

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#!/bin/sh
test_description='git repack works correctly'
. ./test-lib.sh
. "${TEST_DIRECTORY}/lib-bitmap.sh"
. "${TEST_DIRECTORY}/lib-midx.sh"
commit_and_pack () {
test_commit "$@" 1>&2 &&
incrpackid=$(git pack-objects --all --unpacked --incremental .git/objects/pack/pack </dev/null) &&
echo pack-${incrpackid}.pack
}
test_no_missing_in_packs () {
myidx=$(ls -1 .git/objects/pack/*.idx) &&
test_path_is_file "$myidx" &&
git verify-pack -v alt_objects/pack/*.idx >orig.raw &&
sed -n -e "s/^\($OID_REGEX\).*/\1/p" orig.raw | sort >orig &&
git verify-pack -v $myidx >dest.raw &&
cut -d" " -f1 dest.raw | sort >dest &&
comm -23 orig dest >missing &&
test_must_be_empty missing
}
# we expect $packid and $oid to be defined
test_has_duplicate_object () {
want_duplicate_object="$1"
found_duplicate_object=false
for p in .git/objects/pack/*.idx
do
idx=$(basename $p)
test "pack-$packid.idx" = "$idx" && continue
git verify-pack -v $p >packlist || return $?
if grep "^$oid" packlist
then
found_duplicate_object=true
echo "DUPLICATE OBJECT FOUND"
break
fi
done &&
test "$want_duplicate_object" = "$found_duplicate_object"
}
test_expect_success 'objects in packs marked .keep are not repacked' '
echo content1 >file1 &&
echo content2 >file2 &&
git add . &&
test_tick &&
git commit -m initial_commit &&
# Create two packs
# The first pack will contain all of the objects except one
git rev-list --objects --all >objs &&
grep -v file2 objs | git pack-objects pack &&
# The second pack will contain the excluded object
packid=$(grep file2 objs | git pack-objects pack) &&
>pack-$packid.keep &&
git verify-pack -v pack-$packid.idx >packlist &&
oid=$(head -n 1 packlist | sed -e "s/^\($OID_REGEX\).*/\1/") &&
mv pack-* .git/objects/pack/ &&
git repack -A -d -l &&
git prune-packed &&
test_has_duplicate_object false
'
test_expect_success 'writing bitmaps via command-line can duplicate .keep objects' '
# build on $oid, $packid, and .keep state from previous
GIT_TEST_MULTI_PACK_INDEX_WRITE_BITMAP=0 git repack -Adbl &&
test_has_duplicate_object true
'
test_expect_success 'writing bitmaps via config can duplicate .keep objects' '
# build on $oid, $packid, and .keep state from previous
GIT_TEST_MULTI_PACK_INDEX_WRITE_BITMAP=0 \
git -c repack.writebitmaps=true repack -Adl &&
test_has_duplicate_object true
'
test_expect_success 'loose objects in alternate ODB are not repacked' '
mkdir alt_objects &&
echo $(pwd)/alt_objects >.git/objects/info/alternates &&
echo content3 >file3 &&
oid=$(GIT_OBJECT_DIRECTORY=alt_objects git hash-object -w file3) &&
git add file3 &&
test_tick &&
git commit -m commit_file3 &&
git repack -a -d -l &&
git prune-packed &&
test_has_duplicate_object false
'
test_expect_success 'packed obs in alt ODB are repacked even when local repo is packless' '
mkdir alt_objects/pack &&
mv .git/objects/pack/* alt_objects/pack &&
git repack -a &&
test_no_missing_in_packs
'
test_expect_success 'packed obs in alt ODB are repacked when local repo has packs' '
rm -f .git/objects/pack/* &&
echo new_content >>file1 &&
git add file1 &&
test_tick &&
git commit -m more_content &&
git repack &&
git repack -a -d &&
test_no_missing_in_packs
'
test_expect_success 'packed obs in alternate ODB kept pack are repacked' '
# swap the .keep so the commit object is in the pack with .keep
for p in alt_objects/pack/*.pack
do
base_name=$(basename $p .pack) &&
if test_path_is_file alt_objects/pack/$base_name.keep
then
rm alt_objects/pack/$base_name.keep
else
touch alt_objects/pack/$base_name.keep
fi
done &&
git repack -a -d &&
test_no_missing_in_packs
'
test_expect_success 'packed unreachable obs in alternate ODB are not loosened' '
rm -f alt_objects/pack/*.keep &&
mv .git/objects/pack/* alt_objects/pack/ &&
coid=$(git rev-parse HEAD^{commit}) &&
git reset --hard HEAD^ &&
test_tick &&
git reflog expire --expire=$test_tick --expire-unreachable=$test_tick --all &&
# The pack-objects call on the next line is equivalent to
# git repack -A -d without the call to prune-packed
git pack-objects --honor-pack-keep --non-empty --all --reflog \
--unpack-unreachable </dev/null pack &&
rm -f .git/objects/pack/* &&
mv pack-* .git/objects/pack/ &&
git verify-pack -v -- .git/objects/pack/*.idx >packlist &&
! grep "^$coid " packlist &&
echo >.git/objects/info/alternates &&
test_must_fail git show $coid
'
test_expect_success 'local packed unreachable obs that exist in alternate ODB are not loosened' '
echo $(pwd)/alt_objects >.git/objects/info/alternates &&
echo "$coid" | git pack-objects --non-empty --all --reflog pack &&
rm -f .git/objects/pack/* &&
mv pack-* .git/objects/pack/ &&
# The pack-objects call on the next line is equivalent to
# git repack -A -d without the call to prune-packed
git pack-objects --honor-pack-keep --non-empty --all --reflog \
--unpack-unreachable </dev/null pack &&
rm -f .git/objects/pack/* &&
mv pack-* .git/objects/pack/ &&
git verify-pack -v -- .git/objects/pack/*.idx >packlist &&
! grep "^$coid " &&
echo >.git/objects/info/alternates &&
test_must_fail git show $coid
'
test_expect_success 'objects made unreachable by grafts only are kept' '
test_tick &&
git commit --allow-empty -m "commit 4" &&
H0=$(git rev-parse HEAD) &&
H1=$(git rev-parse HEAD^) &&
H2=$(git rev-parse HEAD^^) &&
echo "$H0 $H2" >.git/info/grafts &&
git reflog expire --expire=$test_tick --expire-unreachable=$test_tick --all &&
git repack -a -d &&
git cat-file -t $H1
'
test_expect_success 'repack --keep-pack' '
test_create_repo keep-pack &&
(
cd keep-pack &&
P1=$(commit_and_pack 1) &&
P2=$(commit_and_pack 2) &&
P3=$(commit_and_pack 3) &&
P4=$(commit_and_pack 4) &&
ls .git/objects/pack/*.pack >old-counts &&
test_line_count = 4 old-counts &&
git repack -a -d --keep-pack $P1 --keep-pack $P4 &&
ls .git/objects/pack/*.pack >new-counts &&
grep -q $P1 new-counts &&
grep -q $P4 new-counts &&
test_line_count = 3 new-counts &&
git fsck
)
'
test_expect_success 'bitmaps are created by default in bare repos' '
git clone --bare .git bare.git &&
rm -f bare.git/objects/pack/*.bitmap &&
GIT_TEST_MULTI_PACK_INDEX_WRITE_BITMAP=0 \
git -C bare.git repack -ad &&
bitmap=$(ls bare.git/objects/pack/*.bitmap) &&
test_path_is_file "$bitmap"
'
test_expect_success 'incremental repack does not complain' '
git -C bare.git repack -q 2>repack.err &&
test_must_be_empty repack.err
'
test_expect_success 'bitmaps can be disabled on bare repos' '
GIT_TEST_MULTI_PACK_INDEX_WRITE_BITMAP=0 \
git -c repack.writeBitmaps=false -C bare.git repack -ad &&
bitmap=$(ls bare.git/objects/pack/*.bitmap || :) &&
test -z "$bitmap"
'
test_expect_success 'no bitmaps created if .keep files present' '
pack=$(ls bare.git/objects/pack/*.pack) &&
test_path_is_file "$pack" &&
keep=${pack%.pack}.keep &&
test_when_finished "rm -f \"\$keep\"" &&
>"$keep" &&
GIT_TEST_MULTI_PACK_INDEX_WRITE_BITMAP=0 \
git -C bare.git repack -ad 2>stderr &&
test_must_be_empty stderr &&
find bare.git/objects/pack/ -type f -name "*.bitmap" >actual &&
test_must_be_empty actual
'
test_expect_success 'auto-bitmaps do not complain if unavailable' '
test_config -C bare.git pack.packSizeLimit 1M &&
blob=$(test-tool genrandom big $((1024*1024)) |
git -C bare.git hash-object -w --stdin) &&
git -C bare.git update-ref refs/tags/big $blob &&
GIT_TEST_MULTI_PACK_INDEX_WRITE_BITMAP=0 \
git -C bare.git repack -ad 2>stderr &&
test_must_be_empty stderr &&
find bare.git/objects/pack -type f -name "*.bitmap" >actual &&
test_must_be_empty actual
'
objdir=.git/objects
midx=$objdir/pack/multi-pack-index
test_expect_success 'setup for --write-midx tests' '
git init midx &&
(
cd midx &&
git config core.multiPackIndex true &&
test_commit base
)
'
test_expect_success '--write-midx unchanged' '
(
cd midx &&
GIT_TEST_MULTI_PACK_INDEX=0 git repack &&
test_path_is_missing $midx &&
test_path_is_missing $midx-*.bitmap &&
GIT_TEST_MULTI_PACK_INDEX=0 git repack --write-midx &&
test_path_is_file $midx &&
test_path_is_missing $midx-*.bitmap &&
test_midx_consistent $objdir
)
'
test_expect_success '--write-midx with a new pack' '
(
cd midx &&
test_commit loose &&
GIT_TEST_MULTI_PACK_INDEX=0 git repack --write-midx &&
test_path_is_file $midx &&
test_path_is_missing $midx-*.bitmap &&
test_midx_consistent $objdir
)
'
test_expect_success '--write-midx with -b' '
(
cd midx &&
GIT_TEST_MULTI_PACK_INDEX=0 git repack -mb &&
test_path_is_file $midx &&
test_path_is_file $midx-*.bitmap &&
test_midx_consistent $objdir
)
'
test_expect_success '--write-midx with -d' '
(
cd midx &&
test_commit repack &&
GIT_TEST_MULTI_PACK_INDEX=0 git repack -Ad --write-midx &&
test_path_is_file $midx &&
test_path_is_missing $midx-*.bitmap &&
test_midx_consistent $objdir
)
'
test_expect_success 'cleans up MIDX when appropriate' '
(
cd midx &&
test_commit repack-2 &&
GIT_TEST_MULTI_PACK_INDEX=0 git repack -Adb --write-midx &&
checksum=$(midx_checksum $objdir) &&
test_path_is_file $midx &&
test_path_is_file $midx-$checksum.bitmap &&
test_path_is_file $midx-$checksum.rev &&
test_commit repack-3 &&
GIT_TEST_MULTI_PACK_INDEX=0 git repack -Adb --write-midx &&
test_path_is_file $midx &&
test_path_is_missing $midx-$checksum.bitmap &&
test_path_is_missing $midx-$checksum.rev &&
test_path_is_file $midx-$(midx_checksum $objdir).bitmap &&
test_path_is_file $midx-$(midx_checksum $objdir).rev &&
test_commit repack-4 &&
GIT_TEST_MULTI_PACK_INDEX=0 git repack -Adb &&
find $objdir/pack -type f -name "multi-pack-index*" >files &&
test_must_be_empty files
)
'
test_expect_success '--write-midx with preferred bitmap tips' '
git init midx-preferred-tips &&
test_when_finished "rm -fr midx-preferred-tips" &&
(
cd midx-preferred-tips &&
test_commit_bulk --message="%s" 103 &&
git log --format="%H" >commits.raw &&
sort <commits.raw >commits &&
git log --format="create refs/tags/%s/%s %H" HEAD >refs &&
git update-ref --stdin <refs &&
git repack --write-midx --write-bitmap-index &&
test_path_is_file $midx &&
test_path_is_file $midx-$(midx_checksum $objdir).bitmap &&
test-tool bitmap list-commits | sort >bitmaps &&
comm -13 bitmaps commits >before &&
test_line_count = 1 before &&
rm -fr $midx-$(midx_checksum $objdir).bitmap &&
rm -fr $midx-$(midx_checksum $objdir).rev &&
rm -fr $midx &&
# instead of constructing the snapshot ourselves (c.f., the test
# "write a bitmap with --refs-snapshot (preferred tips)" in
# t5326), mark the missing commit as preferred by adding it to
# the pack.preferBitmapTips configuration.
git for-each-ref --format="%(refname:rstrip=1)" \
--points-at="$(cat before)" >missing &&
git config pack.preferBitmapTips "$(cat missing)" &&
git repack --write-midx --write-bitmap-index &&
test-tool bitmap list-commits | sort >bitmaps &&
comm -13 bitmaps commits >after &&
! test_cmp before after
)
'
test_done