GNU logs - #25427, boring messages

Message sent to bug-diffutils@HIDDEN:

Subject: bug#25427: strip-trailing-cr makes -q not be quick
Resent-From: Tom Vajzovic <t.gnutools@HIDDEN>
Original-Sender: "Debbugs-submit" <debbugs-submit-bounces <at> debbugs.gnu.org>
Resent-CC: bug-diffutils@HIDDEN
Resent-Date: Thu, 12 Jan 2017 16:12:01 +0000
Resent-Message-ID: <handler.25427.B.14842374825304 <at> debbugs.gnu.org>
Resent-Sender: help-debbugs@HIDDEN
To: 25427 <at> debbugs.gnu.org
Date: Thu, 12 Jan 2017 14:37:45 +0000
From: Tom Vajzovic <t.gnutools@HIDDEN>
Message-ID: <20170112143745.7cf5914e@HIDDEN>
MIME-Version: 1.0
Content-Type: text/plain; charset=US-ASCII
Content-Transfer-Encoding: 7bit
Precedence: list
Errors-To: debbugs-submit-bounces <at> debbugs.gnu.org
Sender: "Debbugs-submit" <debbugs-submit-bounces <at> debbugs.gnu.org>

Hi,

I have diff aliased to 'diff -d --strip-trailing-cr'.

When I run 'diff -qs file1 file2' it takes a very long time to return
(minutes).

If I run without the -d it still takes a noticeable amount of time (a
second or two).

If I run without --strip-trailing-cr it takes next-to-no-time, whether
or not I specify -d.

These are two very large text files, but they differ within the first
few lines.

I suspect that it is calculating the whole diff internally and
discarding it when --strip-trailing-cr is given at the same time as -q.

Obviously I understand that by putting --strip-trailing-cr in an alias
I am requiring the whole file to be read and modified in memory, this
is fine.  The fact that -d has any effect though suggests that
once the line endings are processed the wrong algorithm is being
applied.  It doesn't need to run the diff algorithm, something almost
as simple as a strcmp could be used if -q is given, in which case -d
would have no effect.

Are there active developers working on diff that want to look at and
fix this?  I am a C programmer so would be happy to do it myself, but I
have never contributed to GNU tools so I might not do it the way you
would like.  I'd rather not spend time on it if you are likely to reject
it and have to re-write it yourselves anyway.

I'm using version 3.3 from Ubuntu.  Let me know if you want me to
reproduce from master.

Many thanks/best regards,

Tom Vajzovic

Message sent:

Content-Disposition: inline
Content-Transfer-Encoding: quoted-printable
MIME-Version: 1.0
X-Mailer: MIME-tools 5.505 (Entity 5.505)
Content-Type: text/plain; charset=utf-8
X-Loop: help-debbugs@HIDDEN
From: help-debbugs@HIDDEN (GNU bug Tracking System)
To: Tom Vajzovic <t.gnutools@HIDDEN>
Subject: bug#25427: Acknowledgement (strip-trailing-cr makes -q not be quick)
Message-ID: <handler.25427.B.14842374825304.ack <at> debbugs.gnu.org>
References: <20170112143745.7cf5914e@HIDDEN>
X-Gnu-PR-Message: ack 25427
X-Gnu-PR-Package: diffutils
Reply-To: 25427 <at> debbugs.gnu.org
Date: Thu, 12 Jan 2017 16:12:02 +0000

Thank you for filing a new bug report with debbugs.gnu.org.

This is an automatically generated reply to let you know your message
has been received.

Your message is being forwarded to the package maintainers and other
interested parties for their attention; they will reply in due course.

Your message has been sent to the package maintainer(s):
 bug-diffutils@HIDDEN

If you wish to submit further information on this problem, please
send it to 25427 <at> debbugs.gnu.org.

Please do not send mail to help-debbugs@HIDDEN unless you wish
to report a problem with the Bug-tracking system.

--=20
25427: http://debbugs.gnu.org/cgi/bugreport.cgi?bug=3D25427
GNU Bug Tracking System
Contact help-debbugs@HIDDEN with problems

Message sent to bug-diffutils@HIDDEN:

Subject: bug#25427: [bug-diffutils] bug#25427: strip-trailing-cr makes -q not be quick
Resent-From: Paul Eggert <eggert@HIDDEN>
Original-Sender: "Debbugs-submit" <debbugs-submit-bounces <at> debbugs.gnu.org>
Resent-CC: bug-diffutils@HIDDEN
Resent-Date: Thu, 12 Jan 2017 23:39:02 +0000
Resent-Message-ID: <handler.25427.B25427.148426431630778 <at> debbugs.gnu.org>
Resent-Sender: help-debbugs@HIDDEN
To: Tom Vajzovic <t.gnutools@HIDDEN>, 25427 <at> debbugs.gnu.org
References: <20170112143745.7cf5914e@HIDDEN>
From: Paul Eggert <eggert@HIDDEN>
Organization: UCLA Computer Science Department
Message-ID: <1768de52-8245-5358-1912-1ef73f0858d1@HIDDEN>
Date: Thu, 12 Jan 2017 15:38:27 -0800
User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:45.0) Gecko/20100101
 Thunderbird/45.6.0
MIME-Version: 1.0
In-Reply-To: <20170112143745.7cf5914e@HIDDEN>
Content-Type: text/plain; charset=utf-8
Content-Transfer-Encoding: 7bit
Precedence: list
Errors-To: debbugs-submit-bounces <at> debbugs.gnu.org
Sender: "Debbugs-submit" <debbugs-submit-bounces <at> debbugs.gnu.org>

On 01/12/2017 06:37 AM, Tom Vajzovic wrote:
> Are there active developers working on diff that want to look at and
> fix this?  I am a C programmer so would be happy to do it myself, but I
> have never contributed to GNU tools so I might not do it the way you
> would like.  I'd rather not spend time on it if you are likely to reject
> it and have to re-write it yourselves anyway.

That option is low on my priority list so it'd be nice if you could fix
it. Please use the style the code is already using; you can see the GNU
Coding Standards for more details. Most likely your change would be
significant enough that we'd need copyright assignment from you and your
employer; I can send you details about how to do that, privately, if you
like.

Message sent to bug-diffutils@HIDDEN:

Subject: bug#25427: [bug-diffutils] bug#25427: strip-trailing-cr makes -q not be quick
Resent-From: Tom Vajzovic <t.gnutools@HIDDEN>
Original-Sender: "Debbugs-submit" <debbugs-submit-bounces <at> debbugs.gnu.org>
Resent-CC: bug-diffutils@HIDDEN
Resent-Date: Sun, 22 Jan 2017 20:38:01 +0000
Resent-Message-ID: <handler.25427.B25427.148511746816202 <at> debbugs.gnu.org>
Resent-Sender: help-debbugs@HIDDEN
To: Paul Eggert <eggert@HIDDEN>
Cc: 25427 <at> debbugs.gnu.org, Tom Vajzovic <t.gnutools@HIDDEN>
Date: Sun, 22 Jan 2017 20:37:34 +0000
From: Tom Vajzovic <t.gnutools@HIDDEN>
Message-ID: <20170122203734.75f3723c@HIDDEN>
In-Reply-To: <1768de52-8245-5358-1912-1ef73f0858d1@HIDDEN>
References: <20170112143745.7cf5914e@HIDDEN>
 <1768de52-8245-5358-1912-1ef73f0858d1@HIDDEN>
MIME-Version: 1.0
Content-Type: text/plain; charset=US-ASCII
Content-Transfer-Encoding: 7bit
Precedence: list
Errors-To: debbugs-submit-bounces <at> debbugs.gnu.org
Sender: "Debbugs-submit" <debbugs-submit-bounces <at> debbugs.gnu.org>

Hi,

On Thu, 12 Jan 2017 15:38:27 -0800
Paul Eggert <eggert@HIDDEN> wrote:

> On 01/12/2017 06:37 AM, Tom Vajzovic wrote:
> > Are there active developers working on diff that want to look at and
> > fix this?  I am a C programmer so would be happy to do it myself,
> > but I have never contributed to GNU tools so I might not do it the
> > way you would like.  I'd rather not spend time on it if you are
> > likely to reject it and have to re-write it yourselves anyway.  
> 
> That option is low on my priority list so it'd be nice if you could
> fix it. Please use the style the code is already using; you can see
> the GNU Coding Standards for more details. Most likely your change
> would be significant enough that we'd need copyright assignment from
> you and your employer; I can send you details about how to do that,
> privately, if you like.

I'll take this one then.  I'll have time to start looking at it in
about a month from now.

Tom

Last modified: Mon, 25 Nov 2019 12:00:02 UTC

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