From: Junio C Hamano <gitster@pobox.com>
Date: Fri, 14 Jun 2013 22:23:16 GMT
Subject: Re: [PATCH 0/2] recover from "failed to apply delta"
Message-ID: <7vbo78miwb.fsf@alter.siamese.dyndns.org>
In-Reply-To: <20130614215618.GB29138@sigill.intra.peff.net>

Jeff King <peff@peff.net> writes:

>> +     # At the beginning of the REF_DELTA representation of $blob_3,
>> +     # write 20-byte base object name for $blob_1, instead of $blob_2.
>> +     # The binary representation of object name for $blob_1 is found
>> +     # at offset 4 + 4 + 256*4 = 1032 for 20 bytes.
>> +     dd if=${pack}.idx bs=1 count=20 skip=1032 | do_corrupt_object $blob_3 2 20 &&
>> +     test_must_fail git cat-file blob $blob_3 >/dev/null &&
>
> I didn't want to bother coming up with the binary version of the
> REF_DELTA sha1, so I used OFS_DELTA. :)

Yeah, I contemplated on doing something like this

	printf "$(echo $blob_3 | sed -e 's/\(..\)/\\x\1/g')"

but of course printf "\xAA" is not in POSIX and at that point I
punted and instead read from .idx at the known offset ;-)