Re: [PATCH] t5310-pack-bitmaps: fix bogus 'pack-objects to file can use bitmap' test

> The test 'pack-objects to file can use bitmap' added in 645c432d61
> (pack-objects: use reachability bitmap index when generating
> non-stdout pack, 2016-09-10) is silently buggy and doesn't check what
> it's supposed to.
> 
> In 't5310-pack-bitmaps.sh', the 'list_packed_objects' helper function
> does what its name implies by running:
> 
>   git show-index <"$1" | cut -d' ' -f2
> 
> The test in question invokes this function like this:
> 
>   list_packed_objects <packa-$packasha1.idx >packa.objects &&
>   list_packed_objects <packb-$packbsha1.idx >packb.objects &&
>   test_cmp packa.objects packb.objects
> 
> Note how these two callsites don't specify the name of the pack index
> file as the function's parameter, but redirect the function's standard
> input from it.  This triggers an error message from the shell, as it
> has no filename to redirect from in the function, but this error is
> ignored, because it happens upstream of a pipe.  Consequently, both
> invocations produce empty 'pack{a,b}.objects' files, and the
> subsequent 'test_cmp' happily finds those two empty files identical.
> 
> Fix these two 'list_packed_objects' invocations by specifying the pack
> index files as parameters.  Furthermore, eliminate the pipe in that
> function by replacing it with an &&-chained pair of commands using an
> intermediate file, so a failure of 'git show-index' or the shell
> redirection will fail the test.
> 
> Signed-off-by: SZEDER Gábor <szeder.dev@gmail.com>
> ---
>  t/t5310-pack-bitmaps.sh | 7 ++++---
>  1 file changed, 4 insertions(+), 3 deletions(-)
> 
> diff --git a/t/t5310-pack-bitmaps.sh b/t/t5310-pack-bitmaps.sh
> index 6ee4d3f2d9..557bd0d0c0 100755
> --- a/t/t5310-pack-bitmaps.sh
> +++ b/t/t5310-pack-bitmaps.sh
> @@ -9,7 +9,8 @@ objpath () {
>  
>  # show objects present in pack ($1 should be associated *.idx)
>  list_packed_objects () {
> -	git show-index <"$1" | cut -d' ' -f2
> +	git show-index <"$1" >object-list &&
> +	cut -d' ' -f2 object-list
>  }
>  
>  # has_any pattern-file content-file
> @@ -204,8 +205,8 @@ test_expect_success 'pack-objects to file can use bitmap' '
>  	# verify equivalent packs are generated with/without using bitmap index
>  	packasha1=$(git pack-objects --no-use-bitmap-index --all packa </dev/null) &&
>  	packbsha1=$(git pack-objects --use-bitmap-index --all packb </dev/null) &&
> -	list_packed_objects <packa-$packasha1.idx >packa.objects &&
> -	list_packed_objects <packb-$packbsha1.idx >packb.objects &&
> +	list_packed_objects packa-$packasha1.idx >packa.objects &&
> +	list_packed_objects packb-$packbsha1.idx >packb.objects &&
>  	test_cmp packa.objects packb.objects
>  '