Re: [PATCH] p5311: handle spaces in wc(1) output

From: Taylor Blau <me@ttaylorr.com>
Date: Oct 3, 2021, 05:14 UTC
Message-ID: <YVk8SeuDIWwsrdO0@nand.local>
In-Reply-To: <a682e2c8-fecc-906e-0ff6-93de2b311d14@web.de>

On Sat, Oct 02, 2021 at 10:33:18PM +0200, René Scharfe wrote:

> Some implementations of wc(1) align their output with leading spaces,
> even when just a single number is requested, e.g. with "wc -c".  p5311
> runs all tests successfully on such a platform, but fails to aggregate
> their results and reports:

This makes sense, and makes me think that wc's platform-specific implementations are too tricky to use when we are being picky about leading spaces.

In other words, I think that your fix is absolutely correct, but I wonder if test_size should be friendlier in what it accepts, and to chomp off any leading space. So perhaps something like the below would work without any modification to p5311.

--- 8< ---

Subject: [PATCH] t/perf/aggregate.perl: tolerate leading spaces

When using `test_size` with `wc -c`, users on certain platforms can run into issues when `wc` emits leading space characters in its output, which confuses get_times.

Callers could switch to use test_file_size instead of `wc -c` (the former never prints leading space characters, so will always work with test_size regardless of platform), but this is an easy enough spot to miss that we should teach get_times to be more tolerant of the input it accepts.

Teach get_times to do just that by stripping any leading space characters.

Signed-off-by: Taylor Blau <me@ttaylorr.com>
---
 t/perf/aggregate.perl | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/t/perf/aggregate.perl b/t/perf/aggregate.perl
index 82c0df4553..575d2000cc 100755
--- a/t/perf/aggregate.perl
+++ b/t/perf/aggregate.perl
@@ -17,8 +17,8 @@ sub get_times {
 		my $rt = ((defined $1 ? $1 : 0.0)*60+$2)*60+$3;
 		return ($rt, $4, $5);
 	# size
-	} elsif ($line =~ /^\d+$/) {
-		return $&;
+	} elsif ($line =~ /^\s*(\d+)$/) {
+		return $1;
 	} else {
 		die "bad input line: $line";
 	}
--
2.33.0.96.g73915697e6