git/t/t7703-repack-geometric.sh
Taylor Blau 6d08b9d4ca builtin/repack.c: make largest pack preferred
When repacking into a geometric series and writing a multi-pack bitmap,
it is beneficial to have the largest resulting pack be the preferred
object source in the bitmap's MIDX, since selecting the large packs can
lead to fewer broken delta chains and better compression.

Teach 'git repack' to identify this pack and pass it to the MIDX write
machinery in order to mark it as preferred.

Signed-off-by: Taylor Blau <me@ttaylorr.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2021-09-28 21:20:56 -07:00

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#!/bin/sh
test_description='git repack --geometric works correctly'
. ./test-lib.sh
GIT_TEST_MULTI_PACK_INDEX=0
objdir=.git/objects
midx=$objdir/pack/multi-pack-index
test_expect_success '--geometric with no packs' '
git init geometric &&
test_when_finished "rm -fr geometric" &&
(
cd geometric &&
git repack --write-midx --geometric 2 >out &&
test_i18ngrep "Nothing new to pack" out
)
'
test_expect_success '--geometric with one pack' '
git init geometric &&
test_when_finished "rm -fr geometric" &&
(
cd geometric &&
test_commit "base" &&
git repack -d &&
git repack --geometric 2 >out &&
test_i18ngrep "Nothing new to pack" out
)
'
test_expect_success '--geometric with an intact progression' '
git init geometric &&
test_when_finished "rm -fr geometric" &&
(
cd geometric &&
# These packs already form a geometric progression.
test_commit_bulk --start=1 1 && # 3 objects
test_commit_bulk --start=2 2 && # 6 objects
test_commit_bulk --start=4 4 && # 12 objects
find $objdir/pack -name "*.pack" | sort >expect &&
git repack --geometric 2 -d &&
find $objdir/pack -name "*.pack" | sort >actual &&
test_cmp expect actual
)
'
test_expect_success '--geometric with loose objects' '
git init geometric &&
test_when_finished "rm -fr geometric" &&
(
cd geometric &&
# These packs already form a geometric progression.
test_commit_bulk --start=1 1 && # 3 objects
test_commit_bulk --start=2 2 && # 6 objects
# The loose objects are packed together, breaking the
# progression.
test_commit loose && # 3 objects
find $objdir/pack -name "*.pack" | sort >before &&
git repack --geometric 2 -d &&
find $objdir/pack -name "*.pack" | sort >after &&
comm -13 before after >new &&
comm -23 before after >removed &&
test_line_count = 1 new &&
test_must_be_empty removed &&
git repack --geometric 2 -d &&
find $objdir/pack -name "*.pack" | sort >after &&
# The progression (3, 3, 6) is combined into one new pack.
test_line_count = 1 after
)
'
test_expect_success '--geometric with small-pack rollup' '
git init geometric &&
test_when_finished "rm -fr geometric" &&
(
cd geometric &&
test_commit_bulk --start=1 1 && # 3 objects
test_commit_bulk --start=2 1 && # 3 objects
find $objdir/pack -name "*.pack" | sort >small &&
test_commit_bulk --start=3 4 && # 12 objects
test_commit_bulk --start=7 8 && # 24 objects
find $objdir/pack -name "*.pack" | sort >before &&
git repack --geometric 2 -d &&
# Three packs in total; two of the existing large ones, and one
# new one.
find $objdir/pack -name "*.pack" | sort >after &&
test_line_count = 3 after &&
comm -3 small before | tr -d "\t" >large &&
grep -qFf large after
)
'
test_expect_success '--geometric with small- and large-pack rollup' '
git init geometric &&
test_when_finished "rm -fr geometric" &&
(
cd geometric &&
# size(small1) + size(small2) > size(medium) / 2
test_commit_bulk --start=1 1 && # 3 objects
test_commit_bulk --start=2 1 && # 3 objects
test_commit_bulk --start=2 3 && # 7 objects
test_commit_bulk --start=6 9 && # 27 objects &&
find $objdir/pack -name "*.pack" | sort >before &&
git repack --geometric 2 -d &&
find $objdir/pack -name "*.pack" | sort >after &&
comm -12 before after >untouched &&
# Two packs in total; the largest pack from before running "git
# repack", and one new one.
test_line_count = 1 untouched &&
test_line_count = 2 after
)
'
test_expect_success '--geometric ignores kept packs' '
git init geometric &&
test_when_finished "rm -fr geometric" &&
(
cd geometric &&
test_commit kept && # 3 objects
test_commit pack && # 3 objects
KEPT=$(git pack-objects --revs $objdir/pack/pack <<-EOF
refs/tags/kept
EOF
) &&
PACK=$(git pack-objects --revs $objdir/pack/pack <<-EOF
refs/tags/pack
^refs/tags/kept
EOF
) &&
# neither pack contains more than twice the number of objects in
# the other, so they should be combined. but, marking one as
# .kept on disk will "freeze" it, so the pack structure should
# remain unchanged.
touch $objdir/pack/pack-$KEPT.keep &&
find $objdir/pack -name "*.pack" | sort >before &&
git repack --geometric 2 -d &&
find $objdir/pack -name "*.pack" | sort >after &&
# both packs should still exist
test_path_is_file $objdir/pack/pack-$KEPT.pack &&
test_path_is_file $objdir/pack/pack-$PACK.pack &&
# and no new packs should be created
test_cmp before after &&
# Passing --pack-kept-objects causes packs with a .keep file to
# be repacked, too.
git repack --geometric 2 -d --pack-kept-objects &&
find $objdir/pack -name "*.pack" >after &&
test_line_count = 1 after
)
'
test_expect_success '--geometric chooses largest MIDX preferred pack' '
git init geometric &&
test_when_finished "rm -fr geometric" &&
(
cd geometric &&
# These packs already form a geometric progression.
test_commit_bulk --start=1 1 && # 3 objects
test_commit_bulk --start=2 2 && # 6 objects
ls $objdir/pack/pack-*.idx >before &&
test_commit_bulk --start=4 4 && # 12 objects
ls $objdir/pack/pack-*.idx >after &&
git repack --geometric 2 -dbm &&
comm -3 before after | xargs -n 1 basename >expect &&
test-tool read-midx --preferred-pack $objdir >actual &&
test_cmp expect actual
)
'
test_done