Message from discussion Rakudo regex regression
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Date: Fri, 16 Mar 2012 16:56:44 +0000
Subject: Re: [perl #111796] Rakudo regex regression
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Sender: Nicholas Clark <n...@flirble.org>
From: n...@ccl4.org (Nicholas Clark)
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On Fri, Mar 16, 2012 at 07:51:44AM -0700, Moritz Lenz wrote:
> Somwhere between the 2012.02 release and 2012.02-180-g16bf0f4, test 253
> in S05-mass/rx.t started to fail:
> eval_dies_ok '/a|&b/', 'alternation and conjunction (|&) - parse error';
> I have no idea what might caused it, but the proper fix probably
> involves detecting Null Patterns.
Isn't this were a git bisect is a routine way to find out the cause?
(In that, it's proving a very powerful way to find the cause of regressions
in Perl 5 with minimal human effort, a fast machine, and a cup of tea*
And if git bisect on its own isn't easy enough, write a wrapper to automate
as much as possible. I wrote one for perl 5:
which tries to make it as easy as taking your failing 1 liner:
perl -e '... stuff that regressed ...'
and changing that to
.../Porting/bisect.pl -e '... stuff that regressed ...'
and off it goes.
No messing with git bisect start, git bisect run, having to make a wrapper
script, getting the build to build at that revision, getting the test case
round the wrong way, etc ...)
* Or other source of amusement whilst the bisect runs for 15 to 30 minutes