From: Jeff Hostetler Date: Wed, 26 Apr 2017 13:06:37 GMT Subject: Re: [PATCH v8] read-cache: call verify_hdr() in a background thread Message-ID: <5a97967d-5cf2-dc62-7f84-524556a9ca4c@jeffhostetler.com> In-Reply-To: On 4/26/2017 12:34 AM, Junio C Hamano wrote: > Junio C Hamano writes: > >> git@jeffhostetler.com writes: >> >>> From: Jeff Hostetler >>> >>> 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. > By the way, I said I am fine with the two-liner version in Dscho's > message, but I am also OK with this version that does not use a > separate dd and instead does everything in a single invocation of > Perl. As long as you've tested this version, there is no point > replacing it with yet another one. Either version is fine. I'd say use my perl version as I have tested it and it is simple enough and already in the tree. I don't think it's worth the bother to switch it to the dd version. Thanks Jeff > Thanks. > >> -- >8 -- >> From: Jeff Hostetler >> 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 >> ' >>