Re: [PATCH v8] read-cache: call verify_hdr() in a background thread
- From
Junio C Hamano <gitster@pobox.com>
- Date
- Apr 26, 2017, 04:11 UTC
- Message-ID
- <xmqqd1bzst95.fsf@gitster.mtv.corp.google.com>
- In-Reply-To
- <20170425184109.46168-1-git@jeffhostetler.com>
git@jeffhostetler.com writes:
Show 9 quoted lines
> From: Jeff Hostetler <jeffhost@microsoft.com> > > Version 8 of this patch converts the unit test to use > perl to corrupt the index checksum (rather than altering > a filename) and also verifies the fsck error message as > suggested in response to v7 on the mailing list. > > If there are no other suggestions, I think this version > should be considered final.
Oops. The earlier one has already been in 'master' for a few days. Let's make this an incremental update.
Is the description in the following something you are OK with (so that I can add your sign-off)?
Thanks.
-- >8 -- From: Jeff Hostetler <jeffhost@microsoft.com> Date: Tue, 25 Apr 2017 18:41:09 +0000 Subject: t1450: avoid use of "sed" on the index, which is a binary file
The previous step added a path zzzzzzzz to the index, and then used "sed" to replace this string to yyyyyyyy to create a test case where the checksum at the end of the file does not match the contents.
Unfortunately, use of "sed" on a non-text file is not portable. Instead, use a Perl script that seeks to the end and modifies the last byte of the file (where we _know_ stores the trailing checksum).
--- t/t1450-fsck.sh | 33 ++++++++++++++++++++++++++------- 1 file changed, 26 insertions(+), 7 deletions(-)
diff --git a/t/t1450-fsck.sh b/t/t1450-fsck.sh index 677e15a7a4..eff1cd68e9 100755 --- a/t/t1450-fsck.sh +++ b/t/t1450-fsck.sh @@ -689,16 +689,35 @@ test_expect_success 'bogus head does not fallback to all heads' ' ! grep $blob out ' +# Corrupt the checksum on the index. +# Add 1 to the last byte in the SHA. +corrupt_index_checksum () { + perl -w -e ' + use Fcntl ":seek"; + open my $fh, "+<", ".git/index" or die "open: $!"; + binmode $fh; + seek $fh, -1, SEEK_END or die "seek: $!"; + read $fh, my $in_byte, 1 or die "read: $!"; + + $in_value = unpack("C", $in_byte); + $out_value = ($in_value + 1) & 255; + + $out_byte = pack("C", $out_value); + + seek $fh, -1, SEEK_END or die "seek: $!"; + print $fh $out_byte; + close $fh or die "close: $!"; + ' +} + +# Corrupt the checksum on the index and then +# verify that only fsck notices. test_expect_success 'detect corrupt index file in fsck' ' cp .git/index .git/index.backup && test_when_finished "mv .git/index.backup .git/index" && - echo zzzzzzzz >zzzzzzzz && - git add zzzzzzzz && - sed -e "s/zzzzzzzz/yyyyyyyy/" .git/index >.git/index.yyy && - mv .git/index.yyy .git/index && - # Confirm that fsck detects invalid checksum - test_must_fail git fsck --cache && - # Confirm that status no longer complains about invalid checksum + corrupt_index_checksum && + test_must_fail git fsck --cache 2>expect && + grep "bad index file" expect && git status '