Subject: RE: [Breakage] Git v2.21.0-rc0 - t5318 (NonStop)

From: "Randall S. Becker" <[email-masked]>
Date: Sat, 9 Feb 2019 11:55:58 -0500

On February 9, 2019 3:40, Johannes Sixt <[email-masked]> wrote:
> Am 09.02.19 um 05:24 schrieb Jeff King:
> > On Fri, Feb 08, 2019 at 05:53:53PM -0500, Randall S. Becker wrote:
> >
> >>> diff --git a/t/test-lib-functions.sh b/t/test-lib-functions.sh index
> >>> 92cf8f812c..4afab14431 100644
> >>> --- a/t/test-lib-functions.sh
> >>> +++ b/t/test-lib-functions.sh
> >>> @@ -1302,3 +1302,8 @@ test_set_port () {
> >>>  	port=$(($port + ${GIT_TEST_STRESS_JOB_NR:-0}))
> >>>  	eval $var=$port
> >>>  }
> >>> +
> >>> +# Generate an output of $1 bytes of all zeroes (NULs, not ASCII zeroes).
> >>> +gen_zero_bytes () {
> >>> +	perl -e 'print "\0" x $ARGV[0]' "$@"
> >>> +}
> >>
> >> This function does work on platform, so it's good.
> >
> > Great. Since it sounds like you're preparing some patches to deal with
> > /dev/zero elsewhere, do you want to wrap it up in a patch as part of
> > that?
> 
> Please do not use yes to generate an infinite amount of bytes. Our
> implementation of yes() in test-lib.sh generates only 99 lines.
> 
> Perhaps do this.
> 
> ----- 8< -----
> Subject: [PATCH] t5318: avoid /dev/zero
> 
> Some platforms do not offer /dev/zero. Use printf and tr to generate a
> certain amount of NUL bytes.
> 
> Reported-by: Randall S. Becker <[email-masked]>
> Signed-off-by: Johannes Sixt <[email-masked]>
> ---
>  t/t5318-commit-graph.sh | 3 ++-
>  1 file changed, 2 insertions(+), 1 deletion(-)
> 
> diff --git a/t/t5318-commit-graph.sh b/t/t5318-commit-graph.sh index
> 16d10ebce8..04d394274f 100755
> --- a/t/t5318-commit-graph.sh
> +++ b/t/t5318-commit-graph.sh
> @@ -383,7 +383,8 @@ corrupt_graph_and_verify() {
>  	cp $objdir/info/commit-graph commit-graph-backup &&
>  	printf "$data" | dd of="$objdir/info/commit-graph" bs=1
> seek="$pos" conv=notrunc &&
>  	dd of="$objdir/info/commit-graph" bs=1 seek="$zero_pos" count=0
> &&
> -	dd if=/dev/zero of="$objdir/info/commit-graph" bs=1
> seek="$zero_pos" count=$(($orig_size - $zero_pos)) &&
> +	printf "%0*d" $(($orig_size - $zero_pos)) 0 | tr 0 '\0' |
> +		dd of="$objdir/info/commit-graph" bs=1 seek="$zero_pos"
> &&
>  	test_must_fail git commit-graph verify 2>test_err &&
>  	grep -v "^+" test_err >err &&
>  	test_i18ngrep "$grepstr" err
> --
> 2.20.1.86.gb0de946387

This would be fine with me. I'm going to prepare an alternative and let the committers decide.