Junio C Hamano <gitster@xxxxxxxxx> writes:
> git@xxxxxxxxxxxxxxxxx writes:
>
>> From: Jeff Hostetler <jeffhost@xxxxxxxxxxxxx>
>>
>> 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.
Thanks.
> -- >8 --
> From: Jeff Hostetler <jeffhost@xxxxxxxxxxxxx>
> 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
> '
>