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t1450: fix quoting of NUL byte when corrupting pack

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We use

  printf '\0'

to generate a NUL byte which we then `dd` into the packfile to ensure
that we modify the first byte of the first object, thereby
(probabilistically) invalidating the checksum. Except the single quotes
we're using are interpreted to match with the ones we enclose the whole
test in. So we actually execute

  printf \0

and end up injecting the ASCII code for "0", 0x30, instead.

The comment right above this `printf` invocation says that "at least one
of [the type bits] is not zero, so setting the first byte to 0 is
sufficient". Substituting "0x30" for "0" in that comment won't do: we'd
need to reason about which bits go where and just what the packfile
looks like that we're modifying in this test.

Let's avoid all of that by actually executing

  printf "\0"

to generate a NUL byte, as intended.

Signed-off-by: Martin Ågren <martin.agren@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
This commit is contained in:
Martin Ågren 2020-08-02 00:06:11 +02:00 committed by Junio C Hamano
parent b3d7a52fac
commit dc156bc31f
1 changed files with 1 additions and 1 deletions
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2
t/t1450-fsck.sh
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@ -701,7 +701,7 @@ test_expect_success 'fsck fails on corrupt packfile' '
# at least one of which is not zero, so setting the first byte to 0 is
# sufficient.)
chmod a+w .git/objects/pack/pack-$pack.pack &&
printf '\0' | dd of=.git/objects/pack/pack-$pack.pack bs=1 conv=notrunc seek=12 &&
printf "\0" | dd of=.git/objects/pack/pack-$pack.pack bs=1 conv=notrunc seek=12 &&
test_when_finished "rm -f .git/objects/pack/pack-$pack.*" &&
remove_object $hsh &&