GNU bug report logs - #24159
[PATCH] dfa: minor fix for whether dfa is fast or not

Previous Next

Full log

View this message in rfc822 format

From: help-debbugs <at> gnu.org (GNU bug Tracking System)
To: Norihiro Tanaka <noritnk <at> kcn.ne.jp>
Subject: bug#24159: closed (Re: bug#24159: [PATCH] dfa: minor fix for
 whether dfa is fast or not)
Date: Sat, 06 Aug 2016 05:03:02 +0000

[Message part 1 (text/plain, inline)]

Your bug report

#24159: [PATCH] dfa: minor fix for whether dfa is fast or not

which was filed against the grep package, has been closed.

The explanation is attached below, along with your original report.
If you require more details, please reply to 24159 <at> debbugs.gnu.org.

-- 
24159: http://debbugs.gnu.org/cgi/bugreport.cgi?bug=24159
GNU Bug Tracking System
Contact help-debbugs <at> gnu.org with problems

[Message part 2 (message/rfc822, inline)]

From: Jim Meyering <jim <at> meyering.net>
To: Norihiro Tanaka <noritnk <at> kcn.ne.jp>
Cc: 24159-done <at> debbugs.gnu.org
Subject: Re: bug#24159: [PATCH] dfa: minor fix for whether dfa is fast or not
Date: Fri, 5 Aug 2016 22:02:31 -0700

[Message part 3 (text/plain, inline)]

On Fri, Aug 5, 2016 at 7:32 PM, Norihiro Tanaka <noritnk <at> kcn.ne.jp> wrote:
>
> On Fri, 5 Aug 2016 13:29:43 -0700
> Jim Meyering <jim <at> meyering.net> wrote:
>
>> On Fri, Aug 5, 2016 at 4:30 AM, Norihiro Tanaka <noritnk <at> kcn.ne.jp> wrote:
>> > dfaoptimize() is not set fast flag even if it is success, but it is wrong.
>> > If success, dfa matcher uses algorithm for single byte, and it is so fast.
>> >
>> > I think this bug does not affect for grep, but it will affect with the
>> > patch that I just sent to gawk.
>>
>> Thank you for the patch.
>> I was going to push it with the attached slightly updated log message.
>> Note however that grep does use that -> fast member via dfasearch.c's
>> use of the dfaisfast function.
>> But then I realized I should at least verify with "make check", and
>> found that this makes grep's dfa-match test fail.
>> Thus, I will not be pushing it as-is.
>
> Thanks for review and adjustment.  I re-ran all tests including dfa-match,
> and they were passwd again in my machine.  Next, I will re-run them on
> Fedora24, as my machine is RHEL 6.8 and GCC 4.4.7 which is too old.
>
> However, I do not know why dfa-match test fails on your machine.
> dfa-match test does not use grep.  It directly calls dfa functions through
> dfa-match-aux executable in order to test codes of dfa which grep does
> not use.  dfa-match-aux does not referer to the ->fast member.

I have examined the logs, which suggest it was a false positive in a
parallelized "make check" run, due to that test's 3-second timeout. I
have tried repeatedly to reproduce that failure, so far without
success, but in coreutils development, with parallelized tests, we
fixed many hard-to-reproduce tests with small timeout limits like this
-- most of them now use 10 seconds as the limit, so I will change this
one, too (and several others) with the attached patch.

I have pushed your patch.

[0001-tests-standardize-on-10-second-timeouts-to-avoid-rar.diff (text/plain, attachment)]

[Message part 5 (message/rfc822, inline)]

From: Norihiro Tanaka <noritnk <at> kcn.ne.jp>
To: <bug-grep <at> gnu.org>
Subject: [PATCH] dfa: minor fix for whether dfa is fast or not
Date: Fri, 05 Aug 2016 20:30:49 +0900

[Message part 6 (text/plain, inline)]

dfaoptimize() is not set fast flag even if it is success, but it is wrong.
If success, dfa matcher uses algorithm for single byte, and it is so fast.

I think this bug does not affect for grep, but it will affect with the
patch that I just sent to gawk.

[0001-dfa-minor-fix-for-whether-dfa-is-fast-or-not.patch (application/octet-stream, attachment)]

Previous Next

GNU bug tracking system
Copyright (C) 1999 Darren O. Benham, 1997,2003 nCipher Corporation Ltd, 1994-97 Ian Jackson.