On Fri, Jan 29, 2021 at 02:32:50PM -0500, Jeff King wrote:
> > this construct:
> >
> > ... |
> > sed -n '1~5p' |
> > head -n "$1" |
> > ...
> >
> > which is a GNUism. Peff often says that very small population
> > actually run our perf suite, and this seems to corroborate the
> > conjecture.
>
> Oops. Looks like I was the one who introduced that. Nobody seems to have
> complained, so I'm somewhat tempted to leave it. But it would not be too
> hard to replace with perl, I think.
Maybe worth doing this?
-- >8 --
Subject: [PATCH] p5303: avoid sed GNU-ism
Using "1~5" isn't portable. Nobody seems to have noticed, since perhaps
people don't tend to run the perf suite on more exotic platforms. Still,
it's better to set a good example.
We can use:
perl -ne 'print if $. % 5 == 1'
instead. But we can further observe that perl does a good job of the
other parts of this pipeline, and fold the whole thing together.
Signed-off-by: Jeff King <peff@xxxxxxxx>
---
t/perf/p5303-many-packs.sh | 12 ++++++++----
1 file changed, 8 insertions(+), 4 deletions(-)
diff --git a/t/perf/p5303-many-packs.sh b/t/perf/p5303-many-packs.sh
index f4c2ab0584..ce0c42cc9f 100755
--- a/t/perf/p5303-many-packs.sh
+++ b/t/perf/p5303-many-packs.sh
@@ -21,10 +21,14 @@ repack_into_n () {
mkdir staging &&
git rev-list --first-parent HEAD |
- sed -n '1~5p' |
- head -n "$1" |
- perl -e 'print reverse <>' \
- >pushes
+ perl -e '
+ my $n = shift;
+ while (<>) {
+ last unless @commits < $n;
+ push @commits, $_ if $. % 5 == 1;
+ }
+ print reverse @commits;
+ ' "$1" >pushes
# create base packfile
head -n 1 pushes |
--
2.30.0.759.g69d54d14a7
