Re: [PATCH v2 11/22] t5302: make hash size independent

From: Johannes Schindelin <Johannes.Schindelin@gmx.de>
To: "brian m. carlson" <sandals@crustytoothpaste.net>
Cc: git@vger.kernel.org, Eric Sunshine <sunshine@sunshineco.com>
Subject: Re: [PATCH v2 11/22] t5302: make hash size independent
Date: Sun, 26 Jan 2020 23:23:32 +0100 (CET)	[thread overview]
Message-ID: <nycvar.QRO.7.76.6.2001262315150.46@tvgsbejvaqbjf.bet> (raw)
In-Reply-To: <20200125230035.136348-12-sandals@crustytoothpaste.net>

Hi brian,

On Sat, 25 Jan 2020, brian m. carlson wrote:

> Compute the length of object IDs and pack offsets instead of hard-coding
> constants.
>
> Signed-off-by: brian m. carlson <sandals@crustytoothpaste.net>
> ---
>  t/t5302-pack-index.sh | 18 +++++++++++-------
>  1 file changed, 11 insertions(+), 7 deletions(-)
>
> diff --git a/t/t5302-pack-index.sh b/t/t5302-pack-index.sh
> index 91d51b35f9..93ac003639 100755
> --- a/t/t5302-pack-index.sh
> +++ b/t/t5302-pack-index.sh
> @@ -8,7 +8,8 @@ test_description='pack index with 64-bit offsets and object CRC'
>
>  test_expect_success \
>      'setup' \
> -    'rm -rf .git &&
> +    'test_oid_init &&
> +     rm -rf .git &&

Why not consolidate the `test_expect_success` line into the current
convention at the same time ("while at it")? I.e.

	test_expect_success 'setup' '

>       git init &&
>       git config pack.threads 1 &&
>       i=1 &&
> @@ -32,7 +33,9 @@ test_expect_success \
>  	 echo $tree &&
>  	 git ls-tree $tree | sed -e "s/.* \\([0-9a-f]*\\)	.*/\\1/"
>       } >obj-list &&
> -     git update-ref HEAD $commit'
> +     git update-ref HEAD $commit &&
> +     rawsz=$(test_oid rawsz)

Since the `rawsz` assignment has a lot to do with `test_oid_init`, I would
coddle this added line with the `test_oid_init` line above instead of
adding it here.

> +'
>
>  test_expect_success \
>      'pack-objects with index version 1' \
> @@ -152,6 +155,7 @@ test_expect_success \
>      '[index v1] 2) create a stealth corruption in a delta base reference' \
>      '# This test assumes file_101 is a delta smaller than 16 bytes.
>       # It should be against file_100 but we substitute its base for file_099
> +     offset=$((rawsz + 4)) &&
>       sha1_101=$(git hash-object file_101) &&
>       sha1_099=$(git hash-object file_099) &&
>       offs_101=$(index_obj_offset 1.idx $sha1_101) &&
> @@ -159,8 +163,8 @@ test_expect_success \
>       chmod +w ".git/objects/pack/pack-${pack1}.pack" &&
>       dd of=".git/objects/pack/pack-${pack1}.pack" seek=$(($offs_101 + 1)) \
>          if=".git/objects/pack/pack-${pack1}.idx" \
> -        skip=$((4 + 256 * 4 + $nr_099 * 24)) \
> -        bs=1 count=20 conv=notrunc &&
> +        skip=$((4 + 256 * 4 + $nr_099 * offset)) \
> +        bs=1 count=$rawsz conv=notrunc &&

Similarly, the `offset` variable is only used here, so I would assign it
just before the `dd` call. The name `offset` might be a bit to generic not
to be reused, either, maybe `recordsz` or `index_entry_size` or `entrysz`?

Apart from that, the patch looks obviously good to me.

Ciao,
Dscho

P.S.: I'll stop reviewing here for now (It is not that I am tired of
looking at your patches, it is that I am just tired).

>       git cat-file blob $sha1_101 > file_101_foo1'
>
>  test_expect_success \
> @@ -200,8 +204,8 @@ test_expect_success \
>       chmod +w ".git/objects/pack/pack-${pack1}.pack" &&
>       dd of=".git/objects/pack/pack-${pack1}.pack" seek=$(($offs_101 + 1)) \
>          if=".git/objects/pack/pack-${pack1}.idx" \
> -        skip=$((8 + 256 * 4 + $nr_099 * 20)) \
> -        bs=1 count=20 conv=notrunc &&
> +        skip=$((8 + 256 * 4 + $nr_099 * rawsz)) \
> +        bs=1 count=$rawsz conv=notrunc &&
>       git cat-file blob $sha1_101 > file_101_foo2'
>
>  test_expect_success \
> @@ -226,7 +230,7 @@ test_expect_success \
>       nr=$(index_obj_nr ".git/objects/pack/pack-${pack1}.idx" $obj) &&
>       chmod +w ".git/objects/pack/pack-${pack1}.idx" &&
>       printf xxxx | dd of=".git/objects/pack/pack-${pack1}.idx" conv=notrunc \
> -        bs=1 count=4 seek=$((8 + 256 * 4 + $(wc -l <obj-list) * 20 + $nr * 4)) &&
> +        bs=1 count=4 seek=$((8 + 256 * 4 + $(wc -l <obj-list) * rawsz + $nr * 4)) &&
>       ( while read obj
>         do git cat-file -p $obj >/dev/null || exit 1
>         done <obj-list ) &&
>