mirror of
https://github.com/git/git
synced 2024-10-30 04:01:21 +00:00
e3e24de1bf
Back in5b92477f89(builtin/gc.c: conditionally avoid pruning objects via loose, 2022-05-20), `git gc` learned the `--cruft` option and `gc.cruftPacks` configuration to opt-in to writing cruft packs when collecting or pruning unreachable objects. Cruft packs were introduced with the merge ina50036da1a(Merge branch 'tb/cruft-packs', 2022-06-03). They address the problem of "loose object explosions", where Git will write out many individual loose objects when there is a large number of unreachable objects that have not yet aged past `--prune=<date>`. Instead of keeping track of those unreachable yet recent objects via their loose object file's mtime, cruft packs collect all unreachable objects into a single pack with a corresponding `*.mtimes` file that acts as a table to store the mtimes of all unreachable objects. This prevents the need to store unreachable objects as loose as they age out of the repository, and avoids the problem of loose object explosions. Beyond avoiding loose object explosions, cruft packs also act as a more efficient mechanism to store unreachable objects as they age out of a repository. This is because pairs of similar unreachable objects serve as delta bases for one another. In5b92477f89, the feature was introduced as experimental. Since then, GitHub has been running these patches in every repository generating hundreds of millions of cruft packs along the way. The feature is battle-tested, and avoids many pathological cases such as above. Users who either run `git gc` manually, or via `git maintenance` can benefit from having cruft packs. As such, enable cruft pack generation to take place by default (by making `gc.cruftPacks` have the default of "true" rather than "false). Signed-off-by: Taylor Blau <me@ttaylorr.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
368 lines
9.9 KiB
Bash
Executable file
368 lines
9.9 KiB
Bash
Executable file
#!/bin/sh
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test_description='basic git gc tests
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'
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. ./test-lib.sh
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. "$TEST_DIRECTORY"/lib-terminal.sh
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test_expect_success 'setup' '
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# do not let the amount of physical memory affects gc
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# behavior, make sure we always pack everything to one pack by
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# default
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git config gc.bigPackThreshold 2g &&
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# These are simply values which, when hashed as a blob with a newline,
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# produce a hash where the first byte is 0x17 in their respective
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# algorithms.
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test_oid_cache <<-EOF
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obj1 sha1:263
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obj1 sha256:34
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obj2 sha1:410
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obj2 sha256:174
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obj3 sha1:523
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obj3 sha256:313
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obj4 sha1:790
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obj4 sha256:481
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EOF
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'
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test_expect_success 'gc empty repository' '
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git gc
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'
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test_expect_success 'gc does not leave behind pid file' '
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git gc &&
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test_path_is_missing .git/gc.pid
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'
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test_expect_success 'gc --gobbledegook' '
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test_expect_code 129 git gc --nonsense 2>err &&
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test_i18ngrep "[Uu]sage: git gc" err
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'
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test_expect_success 'gc -h with invalid configuration' '
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mkdir broken &&
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(
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cd broken &&
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git init &&
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echo "[gc] pruneexpire = CORRUPT" >>.git/config &&
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test_expect_code 129 git gc -h >usage 2>&1
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) &&
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test_i18ngrep "[Uu]sage" broken/usage
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'
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test_expect_success 'gc is not aborted due to a stale symref' '
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git init remote &&
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(
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cd remote &&
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test_commit initial &&
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git clone . ../client &&
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git branch -m develop &&
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cd ../client &&
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git fetch --prune &&
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git gc
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)
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'
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test_expect_success 'gc --keep-largest-pack' '
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test_create_repo keep-pack &&
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(
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cd keep-pack &&
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test_commit one &&
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test_commit two &&
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test_commit three &&
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git gc &&
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( cd .git/objects/pack && ls *.pack ) >pack-list &&
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test_line_count = 1 pack-list &&
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cp pack-list base-pack-list &&
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test_commit four &&
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git repack -d &&
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test_commit five &&
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git repack -d &&
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( cd .git/objects/pack && ls *.pack ) >pack-list &&
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test_line_count = 3 pack-list &&
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git gc --keep-largest-pack &&
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( cd .git/objects/pack && ls *.pack ) >pack-list &&
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test_line_count = 2 pack-list &&
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awk "/^P /{print \$2}" <.git/objects/info/packs >pack-info &&
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test_line_count = 2 pack-info &&
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test_path_is_file .git/objects/pack/$(cat base-pack-list) &&
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git fsck
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)
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'
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test_expect_success 'pre-auto-gc hook can stop auto gc' '
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cat >err.expect <<-\EOF &&
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no gc for you
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EOF
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git init pre-auto-gc-hook &&
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test_hook -C pre-auto-gc-hook pre-auto-gc <<-\EOF &&
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echo >&2 no gc for you &&
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exit 1
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EOF
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(
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cd pre-auto-gc-hook &&
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git config gc.auto 3 &&
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git config gc.autoDetach false &&
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# We need to create two object whose sha1s start with 17
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# since this is what git gc counts. As it happens, these
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# two blobs will do so.
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test_commit "$(test_oid obj1)" &&
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test_commit "$(test_oid obj2)" &&
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git gc --auto >../out.actual 2>../err.actual
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) &&
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test_must_be_empty out.actual &&
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test_cmp err.expect err.actual &&
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cat >err.expect <<-\EOF &&
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will gc for you
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Auto packing the repository for optimum performance.
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See "git help gc" for manual housekeeping.
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EOF
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test_hook -C pre-auto-gc-hook --clobber pre-auto-gc <<-\EOF &&
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echo >&2 will gc for you &&
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exit 0
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EOF
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git -C pre-auto-gc-hook gc --auto >out.actual 2>err.actual &&
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test_must_be_empty out.actual &&
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test_cmp err.expect err.actual
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'
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test_expect_success 'auto gc with too many loose objects does not attempt to create bitmaps' '
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test_config gc.auto 3 &&
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test_config gc.autodetach false &&
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test_config pack.writebitmaps true &&
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# We need to create two object whose sha1s start with 17
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# since this is what git gc counts. As it happens, these
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# two blobs will do so.
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test_commit "$(test_oid obj1)" &&
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test_commit "$(test_oid obj2)" &&
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# Our first gc will create a pack; our second will create a second pack
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git gc --auto &&
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ls .git/objects/pack/pack-*.pack | sort >existing_packs &&
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test_commit "$(test_oid obj3)" &&
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test_commit "$(test_oid obj4)" &&
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git gc --auto 2>err &&
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test_i18ngrep ! "^warning:" err &&
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ls .git/objects/pack/pack-*.pack | sort >post_packs &&
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comm -1 -3 existing_packs post_packs >new &&
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comm -2 -3 existing_packs post_packs >del &&
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test_line_count = 0 del && # No packs are deleted
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test_line_count = 1 new # There is one new pack
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'
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test_expect_success 'gc --no-quiet' '
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GIT_PROGRESS_DELAY=0 git -c gc.writeCommitGraph=true gc --no-quiet >stdout 2>stderr &&
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test_must_be_empty stdout &&
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test_i18ngrep "Computing commit graph generation numbers" stderr
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'
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test_expect_success TTY 'with TTY: gc --no-quiet' '
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test_terminal env GIT_PROGRESS_DELAY=0 \
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git -c gc.writeCommitGraph=true gc --no-quiet >stdout 2>stderr &&
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test_must_be_empty stdout &&
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test_i18ngrep "Enumerating objects" stderr &&
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test_i18ngrep "Computing commit graph generation numbers" stderr
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'
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test_expect_success 'gc --quiet' '
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git -c gc.writeCommitGraph=true gc --quiet >stdout 2>stderr &&
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test_must_be_empty stdout &&
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test_must_be_empty stderr
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'
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test_expect_success 'gc.reflogExpire{Unreachable,}=never skips "expire" via "gc"' '
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test_config gc.reflogExpire never &&
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test_config gc.reflogExpireUnreachable never &&
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GIT_TRACE=$(pwd)/trace.out git gc &&
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# Check that git-pack-refs is run as a sanity check (done via
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# gc_before_repack()) but that git-expire is not.
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grep -E "^trace: (built-in|exec|run_command): git pack-refs --" trace.out &&
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! grep -E "^trace: (built-in|exec|run_command): git reflog expire --" trace.out
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'
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test_expect_success 'one of gc.reflogExpire{Unreachable,}=never does not skip "expire" via "gc"' '
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>trace.out &&
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test_config gc.reflogExpire never &&
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GIT_TRACE=$(pwd)/trace.out git gc &&
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grep -E "^trace: (built-in|exec|run_command): git reflog expire --" trace.out
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'
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prepare_cruft_history () {
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test_commit base &&
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test_commit --no-tag foo &&
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test_commit --no-tag bar &&
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git reset HEAD^^
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}
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assert_no_cruft_packs () {
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find .git/objects/pack -name "*.mtimes" >mtimes &&
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test_must_be_empty mtimes
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}
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for argv in \
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"gc" \
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"-c gc.cruftPacks=true gc" \
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"-c gc.cruftPacks=false gc --cruft"
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do
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test_expect_success "git $argv generates a cruft pack" '
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test_when_finished "rm -fr repo" &&
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git init repo &&
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(
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cd repo &&
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prepare_cruft_history &&
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git $argv &&
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find .git/objects/pack -name "*.mtimes" >mtimes &&
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sed -e 's/\.mtimes$/\.pack/g' mtimes >packs &&
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test_file_not_empty packs &&
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while read pack
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do
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test_path_is_file "$pack" || return 1
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done <packs
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)
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'
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done
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for argv in \
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"gc --no-cruft" \
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"-c gc.cruftPacks=false gc" \
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"-c gc.cruftPacks=true gc --no-cruft"
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do
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test_expect_success "git $argv does not generate a cruft pack" '
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test_when_finished "rm -fr repo" &&
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git init repo &&
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(
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cd repo &&
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prepare_cruft_history &&
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git $argv &&
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assert_no_cruft_packs
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)
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'
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done
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test_expect_success '--keep-largest-pack ignores cruft packs' '
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test_when_finished "rm -fr repo" &&
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git init repo &&
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(
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cd repo &&
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# Generate a pack for reachable objects (of which there
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# are 3), and one for unreachable objects (of which
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# there are 6).
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prepare_cruft_history &&
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git gc --cruft &&
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mtimes="$(find .git/objects/pack -type f -name "pack-*.mtimes")" &&
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sz="$(test_file_size "${mtimes%.mtimes}.pack")" &&
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# Ensure that the cruft pack gets removed (due to
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# `--prune=now`) despite it being the largest pack.
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git -c gc.bigPackThreshold=$sz gc --cruft --prune=now &&
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assert_no_cruft_packs
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)
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'
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test_expect_success 'gc.bigPackThreshold ignores cruft packs' '
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test_when_finished "rm -fr repo" &&
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git init repo &&
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(
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cd repo &&
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# Generate a pack for reachable objects (of which there
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# are 3), and one for unreachable objects (of which
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# there are 6).
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prepare_cruft_history &&
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git gc --cruft &&
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# Ensure that the cruft pack gets removed (due to
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# `--prune=now`) despite it being the largest pack.
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git gc --cruft --prune=now --keep-largest-pack &&
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assert_no_cruft_packs
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)
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'
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run_and_wait_for_auto_gc () {
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# We read stdout from gc for the side effect of waiting until the
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# background gc process exits, closing its fd 9. Furthermore, the
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# variable assignment from a command substitution preserves the
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# exit status of the main gc process.
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# Note: this fd trickery doesn't work on Windows, but there is no
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# need to, because on Win the auto gc always runs in the foreground.
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doesnt_matter=$(git gc --auto 9>&1)
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}
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test_expect_success 'background auto gc does not run if gc.log is present and recent but does if it is old' '
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test_commit foo &&
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test_commit bar &&
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git repack &&
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test_config gc.autopacklimit 1 &&
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test_config gc.autodetach true &&
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echo fleem >.git/gc.log &&
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git gc --auto 2>err &&
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test_i18ngrep "^warning:" err &&
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test_config gc.logexpiry 5.days &&
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test-tool chmtime =-345600 .git/gc.log &&
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git gc --auto &&
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test_config gc.logexpiry 2.days &&
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run_and_wait_for_auto_gc &&
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ls .git/objects/pack/pack-*.pack >packs &&
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test_line_count = 1 packs
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'
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test_expect_success 'background auto gc respects lock for all operations' '
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# make sure we run a background auto-gc
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test_commit make-pack &&
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git repack &&
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test_config gc.autopacklimit 1 &&
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test_config gc.autodetach true &&
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# create a ref whose loose presence we can use to detect a pack-refs run
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git update-ref refs/heads/should-be-loose HEAD &&
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(ls -1 .git/refs/heads .git/reftable >expect || true) &&
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# now fake a concurrent gc that holds the lock; we can use our
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# shell pid so that it looks valid.
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hostname=$(hostname || echo unknown) &&
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shell_pid=$$ &&
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if test_have_prereq MINGW && test -f /proc/$shell_pid/winpid
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then
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# In Git for Windows, Bash (actually, the MSYS2 runtime) has a
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# different idea of PIDs than git.exe (actually Windows). Use
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# the Windows PID in this case.
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shell_pid=$(cat /proc/$shell_pid/winpid)
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fi &&
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printf "%d %s" "$shell_pid" "$hostname" >.git/gc.pid &&
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# our gc should exit zero without doing anything
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run_and_wait_for_auto_gc &&
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(ls -1 .git/refs/heads .git/reftable >actual || true) &&
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test_cmp expect actual
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'
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# DO NOT leave a detached auto gc process running near the end of the
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# test script: it can run long enough in the background to racily
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# interfere with the cleanup in 'test_done'.
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test_done
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