GNU bug report logs - #21023
REQUEST: --no-dereference missing from manpage + please make a short option for it

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Message #5 received at submit <at> debbugs.gnu.org (full text, mbox):

From: Christoph Anton Mitterer <calestyo <at> scientia.net>
To: bug-diffutils <at> gnu.org
Subject: REQUEST: --no-dereference missing from manpage + please make a
 short option for it
Date: Fri, 10 Jul 2015 02:42:57 +0200

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

Hey.

It seems that --no-dereference is not documented in the manpage.


Apart from that, --no-dereference seem to me like the more native way
for a recursive diff to work,... i.e. diffing the values of symlinks
and not (recursively) the stuff they point to.

Since no-dereference is so helpful, could you perhaps add a shortcut -R
that is recursive + no-dereference?


Unfortunately it's probably too late to change -r to behave like --no
-dereference (and instead add a --dereference and a -R).


Best wishes,
Chris.

[smime.p7s (application/x-pkcs7-signature, attachment)]

Message #8 received at 21023 <at> debbugs.gnu.org (full text, mbox):

From: Jim Meyering <jim <at> meyering.net>
To: Christoph Anton Mitterer <calestyo <at> scientia.net>
Cc: 21023 <at> debbugs.gnu.org
Subject: Re: [bug-diffutils] bug#21023: REQUEST: --no-dereference missing from
 manpage + please make a short option for it
Date: Fri, 10 Jul 2015 11:54:37 -0700

On Thu, Jul 9, 2015 at 5:42 PM, Christoph Anton Mitterer
<calestyo <at> scientia.net> wrote:
> It seems that --no-dereference is not documented in the manpage.

Thanks for the report.
However, it is there for me (using diff-3.3), both in "diff --help"
output and in "info diffutils":

   $ diff --help|grep no-d
      --no-dereference            don't follow symbolic links

From "info diffutils":

  '--no-dereference'
       Act on symbolic links themselves instead of what they point to.

> Apart from that, --no-dereference seem to me like the more native way
> for a recursive diff to work,... i.e. diffing the values of symlinks
> and not (recursively) the stuff they point to.

It's hard to know which way is more intuitive for more people.

> Since no-dereference is so helpful, could you perhaps add a shortcut -R
> that is recursive + no-dereference?

We add short options only very rarely/carefully, because doing so
risks conflicting with usage in other versions of diff.

> Unfortunately it's probably too late to change -r to behave like --no
> -dereference (and instead add a --dereference and a -R).

-P will eventually be a synonym for --no-dereference.
It used to be documented to mean --unidirectional-new-file,
but that was undocumented in 2002.  It is time now to emit
a warning for use of -P, so that we can eventually make it
a synonym for --no-dereference as it is done in numerous
other tools.

Message #11 received at 21023 <at> debbugs.gnu.org (full text, mbox):

From: Rodrigo Valiña Gutiérrez <rodrivg <at> gmail.com>
To: 21023 <at> debbugs.gnu.org
Subject: --no-dereference
Date: Mon, 31 Aug 2015 18:59:14 +0200

--no-dereference appears in 'diff --help' and 'info diffutils', but
not in 'man diff'.

Message #16 received at 21023-done <at> debbugs.gnu.org (full text, mbox):

From: Jim Meyering <jim <at> meyering.net>
To: Rodrigo Valiña Gutiérrez <rodrivg <at> gmail.com>
Cc: 21023-done <at> debbugs.gnu.org
Subject: Re: [bug-diffutils] bug#21023: --no-dereference
Date: Mon, 31 Aug 2015 12:54:44 -0700

tags 21023 notabug
thanks

On Mon, Aug 31, 2015 at 9:59 AM, Rodrigo Valiña Gutiérrez
<rodrivg <at> gmail.com> wrote:
> --no-dereference appears in 'diff --help' and 'info diffutils', but
> not in 'man diff'.

Thanks for the report, but that is unlikely to be a problem with this
upstream diffutils package, since the man page (diff.1) is
automatically generated from the output of diff --help, and the build
machinery to do that has been in place for over a decade. I would
suspect whatever installed your diff man pages or the configuration of
your "man(1)" program -- maybe it is searching in the wrong place.

I'm closing the auto-generated ticket in our bug-tracking system, but
please reply here (we'll still see it) if you think there is something
we can improve on this front.

Message #19 received at 21023 <at> debbugs.gnu.org (full text, mbox):

From: Rodrigo Valiña Gutiérrez <rodrivg <at> gmail.com>
To: Jim Meyering <jim <at> meyering.net>
Cc: 21023 <at> debbugs.gnu.org
Subject: Re: [bug-diffutils] bug#21023: --no-dereference
Date: Mon, 31 Aug 2015 22:04:06 +0200

On 8/31/15, Jim Meyering <jim <at> meyering.net> wrote:
> tags 21023 notabug
> thanks
>
> On Mon, Aug 31, 2015 at 9:59 AM, Rodrigo Valiña Gutiérrez
> <rodrivg <at> gmail.com> wrote:
>> --no-dereference appears in 'diff --help' and 'info diffutils', but
>> not in 'man diff'.
>
> Thanks for the report, but that is unlikely to be a problem with this
> upstream diffutils package, since the man page (diff.1) is
> automatically generated from the output of diff --help, and the build
> machinery to do that has been in place for over a decade. I would
> suspect whatever installed your diff man pages or the configuration of
> your "man(1)" program -- maybe it is searching in the wrong place.

Thanks for the reply.
I downloaded diffutils-3.3.tar.xz and in diffutils-3.3/man/diff.1 does
not appear the --no-dereference option. I don't know whether it is
re-generated at compile or install time... but at the moment that file
does not have the said option.

Message #22 received at 21023 <at> debbugs.gnu.org (full text, mbox):

From: Jim Meyering <jim <at> meyering.net>
To: Rodrigo Valiña Gutiérrez <rodrivg <at> gmail.com>
Cc: 21023 <at> debbugs.gnu.org
Subject: Re: [bug-diffutils] bug#21023: --no-dereference
Date: Mon, 31 Aug 2015 13:42:40 -0700

reopen 21023
tags 21023 -notabug
thanks

On Mon, Aug 31, 2015 at 1:04 PM, Rodrigo Valiña Gutiérrez
<rodrivg <at> gmail.com> wrote:
> On 8/31/15, Jim Meyering <jim <at> meyering.net> wrote:
>> tags 21023 notabug
>> thanks
>>
>> On Mon, Aug 31, 2015 at 9:59 AM, Rodrigo Valiña Gutiérrez
>> <rodrivg <at> gmail.com> wrote:
>>> --no-dereference appears in 'diff --help' and 'info diffutils', but
>>> not in 'man diff'.
>>
>> Thanks for the report, but that is unlikely to be a problem with this
>> upstream diffutils package, since the man page (diff.1) is
>> automatically generated from the output of diff --help, and the build
>> machinery to do that has been in place for over a decade. I would
>> suspect whatever installed your diff man pages or the configuration of
>> your "man(1)" program -- maybe it is searching in the wrong place.
>
> Thanks for the reply.
> I downloaded diffutils-3.3.tar.xz and in diffutils-3.3/man/diff.1 does
> not appear the --no-dereference option. I don't know whether it is
> re-generated at compile or install time... but at the moment that file
> does not have the said option.

Oh, I see that you are right! So this *is* a bug. Reopening and untagging.
It looks like I managed to include a stale diff.1 (not including the
then-new --no-dereference description) in the distribution tarball.
That makes me think there is or was a missing dependency.  I'll
investigate and report back here.

Message #25 received at 21023 <at> debbugs.gnu.org (full text, mbox):

From: Jim Meyering <jim <at> meyering.net>
To: Rodrigo Valiña Gutiérrez <rodrivg <at> gmail.com>
Cc: 21023 <at> debbugs.gnu.org
Subject: Re: [bug-diffutils] bug#21023: bug#21023: --no-dereference
Date: Mon, 31 Aug 2015 23:14:02 -0700

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

On Mon, Aug 31, 2015 at 1:42 PM, Jim Meyering <jim <at> meyering.net> wrote:
> reopen 21023
> tags 21023 -notabug
> thanks
>
> On Mon, Aug 31, 2015 at 1:04 PM, Rodrigo Valiña Gutiérrez
> <rodrivg <at> gmail.com> wrote:
>> On 8/31/15, Jim Meyering <jim <at> meyering.net> wrote:
>>> tags 21023 notabug
>>> thanks
>>>
>>> On Mon, Aug 31, 2015 at 9:59 AM, Rodrigo Valiña Gutiérrez
>>> <rodrivg <at> gmail.com> wrote:
>>>> --no-dereference appears in 'diff --help' and 'info diffutils', but
>>>> not in 'man diff'.
>>>
>>> Thanks for the report, but that is unlikely to be a problem with this
>>> upstream diffutils package, since the man page (diff.1) is
>>> automatically generated from the output of diff --help, and the build
>>> machinery to do that has been in place for over a decade. I would
>>> suspect whatever installed your diff man pages or the configuration of
>>> your "man(1)" program -- maybe it is searching in the wrong place.
>>
>> Thanks for the reply.
>> I downloaded diffutils-3.3.tar.xz and in diffutils-3.3/man/diff.1 does
>> not appear the --no-dereference option. I don't know whether it is
>> re-generated at compile or install time... but at the moment that file
>> does not have the said option.
>
> Oh, I see that you are right! So this *is* a bug. Reopening and untagging.
> It looks like I managed to include a stale diff.1 (not including the
> then-new --no-dereference description) in the distribution tarball.
> That makes me think there is or was a missing dependency.  I'll
> investigate and report back here.

Found the bug. Here's the fix:

[0001-build-correct-man-page-generation-rule.patch (text/x-patch, attachment)]

Message #28 received at 21023-done <at> debbugs.gnu.org (full text, mbox):

From: Jim Meyering <jim <at> meyering.net>
To: Rodrigo Valiña Gutiérrez <rodrivg <at> gmail.com>
Cc: 21023-done <at> debbugs.gnu.org
Subject: Re: [bug-diffutils] bug#21023: bug#21023: bug#21023: --no-dereference
Date: Tue, 1 Sep 2015 21:18:46 -0700

On Mon, Aug 31, 2015 at 11:14 PM, Jim Meyering <jim <at> meyering.net> wrote:
> Found the bug. Here's the fix:

Thanks again, Rodrigo.

I've pushed that with a small improvement to help prevent
a repeat of that problem:

  http://git.savannah.gnu.org/cgit/diffutils.git/commit/?id=2cd4ff3a5ff52d89

At the same time, I pushed a documentation-improving patch that
had been collecting dust:

  http://git.savannah.gnu.org/cgit/diffutils.git/commit/?id=5801f8add854c84

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