Bug#651696: Please use a different variable name than slots in keymaker.h

[Olly Betts]

tags 651696 + pending fixed-upstream
thanks

On Sun, Dec 11, 2011 at 02:39:20PM +0100, Kai Wasserbäch wrote:
> Olly Betts schrieb am 11.12.2011 14:31:
> > On Sun, Dec 11, 2011 at 01:48:57PM +0100, Kai Wasserbäch wrote:
> >> I've been busy packaging (or rather making fit for release) QApt, which
> >> uses Xapian. Currently QApt and some other programs also using Qt (e.g.
> >> packagesearch [0]) need to employ a workaround [1] to be able to use
> >> both Qt and Xapian in conjunction. This is because both Qt and Xapian
> >> have "slots".
> > 
> > Hmm, "slots" is a class member in Xapian.  Is Qt really defining "slots"
> > as a pre-processor macro?  Haven't they heard of not polluting the
> > global namespace?
> 
> I think they have, by now. I can only guess here, but as the slots stuff is
> one of the older but still core parts of Qt, I suspect they didn't care _too_
> much back then. One can use Q_SLOTS today. But slots will still be there in
> the headers.

You can disable Qt's macro definitions for slots, etc with no_keywords:

http://qt-project.org/doc/qt-4.7/signalsandslots.html#id-5f48cb91-f39a-4dda-a168-4fe9bdd07e49

I think promoting use of no_keywords and Q_SLOTS is the best solution.
It's not sensible for Qt to own a generic token like slots and force
the rest of the world to stop using it.  Even acting as if they own
"Q_*" seems unhelpful - there are only 26 single letter prefixes.

I've added a check to the Xapian header upstream for 1.2.11 which gives
a clear error if slots and Q_OBJECT are defined, suggesting including
 first or using no_keywords.

Cheers,
Olly



--
To UNSUBSCRIBE, email to debian-bugs-dist-requ...@lists.debian.org
with a subject of "unsubscribe". Trouble? Contact listmas...@lists.debian.org

Bug#651696: Please use a different variable name than slots in keymaker.h

[Kai Wasserbäch]

Dear Olly,
Olly Betts schrieb am 11.12.2011 14:31:
> On Sun, Dec 11, 2011 at 01:48:57PM +0100, Kai Wasserbäch wrote:
>> I've been busy packaging (or rather making fit for release) QApt, which
>> uses Xapian. Currently QApt and some other programs also using Qt (e.g.
>> packagesearch [0]) need to employ a workaround [1] to be able to use
>> both Qt and Xapian in conjunction. This is because both Qt and Xapian
>> have "slots".
> 
> Hmm, "slots" is a class member in Xapian.  Is Qt really defining "slots"
> as a pre-processor macro?  Haven't they heard of not polluting the
> global namespace?

I think they have, by now. I can only guess here, but as the slots stuff is one
of the older but still core parts of Qt, I suspect they didn't care _too_ much
back then. One can use Q_SLOTS today. But slots will still be there in the 
headers.

> And if so, why not just include xapian.h *first*?

I could do that too and can propose the required changes to QApt's upstream, but
I'd prefer, if both Xapian and Qt could be used alongside each other without
such requirements.

>> Hence I'd like to ask you to consider changing "slots" in keymaker.h
>> (and of course the other files including keymaker.h) to something
>> different. I know this would require some more work from the packages
>> using Xapian, but the amount seems way smaller than changing all Qt
>> packages.
> 
> I think that would mean an incompatible ABI change - if so, it certainly
> can't happen in the 1.2.x series.  

That'd be great. As you can see from the chosen severity, this is nothing I find
too pressing. It's just, that I suspect others might encounter this problem too
and in the long run it might be easier to just change one side. But this is
absolutely your call and if you prefer not to do this, then tag #651696 wontfix
and I forward the appropriate changes to QApt's upstream.

Kind regards,
Kai Wasserbäch



-- 

E-Mail: cu...@debian.org
IRC: Curan
Jabber: dri...@debianforum.de
URL: http://wiki.debian.org/C%C3%B9ran
GnuPG: 0xE1DE59D2  0600 96CE F3C8 E733 E5B6 1587 A309 D76C E1DE 59D2



signature.asc
Description: OpenPGP digital signature

Bug#651696: Please use a different variable name than slots in keymaker.h

[Olly Betts]

On Sun, Dec 11, 2011 at 01:48:57PM +0100, Kai Wasserbäch wrote:
> I've been busy packaging (or rather making fit for release) QApt, which
> uses Xapian. Currently QApt and some other programs also using Qt (e.g.
> packagesearch [0]) need to employ a workaround [1] to be able to use
> both Qt and Xapian in conjunction. This is because both Qt and Xapian
> have "slots".

Hmm, "slots" is a class member in Xapian.  Is Qt really defining "slots"
as a pre-processor macro?  Haven't they heard of not polluting the
global namespace?

And if so, why not just include xapian.h *first*?

> Hence I'd like to ask you to consider changing "slots" in keymaker.h
> (and of course the other files including keymaker.h) to something
> different. I know this would require some more work from the packages
> using Xapian, but the amount seems way smaller than changing all Qt
> packages.

I think that would mean an incompatible ABI change - if so, it certainly
can't happen in the 1.2.x series.  

Cheers,
Olly



-- 
To UNSUBSCRIBE, email to debian-bugs-dist-requ...@lists.debian.org
with a subject of "unsubscribe". Trouble? Contact listmas...@lists.debian.org

Bug#651696: Please use a different variable name than slots in keymaker.h

[Kai Wasserbäch]

Package: xapian-core
Version: 1.2.7-1
Severity: wishlist

-BEGIN PGP SIGNED MESSAGE-
Hash: SHA1

Dear xapian maintainers,
I've been busy packaging (or rather making fit for release) QApt, which
uses Xapian. Currently QApt and some other programs also using Qt (e.g.
packagesearch [0]) need to employ a workaround [1] to be able to use
both Qt and Xapian in conjunction. This is because both Qt and Xapian
have "slots".

Hence I'd like to ask you to consider changing "slots" in keymaker.h
(and of course the other files including keymaker.h) to something
different. I know this would require some more work from the packages
using Xapian, but the amount seems way smaller than changing all Qt
packages.

Thank you in advance!

Kind regards,
Kai Wasserbäch


[0] 
[1]



- -- System Information:
Debian Release: wheezy/sid
  APT prefers testing
  APT policy: (900, 'testing')
Architecture: amd64 (x86_64)

Kernel: Linux 3.1.5-esgaroth (SMP w/4 CPU cores)
Locale: LANG=de_DE.UTF-8, LC_CTYPE=de_DE.UTF-8 (charmap=UTF-8)
Shell: /bin/sh linked to /bin/dash

-BEGIN PGP SIGNATURE-
Version: GnuPG v1.4.11 (GNU/Linux)
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=eEnX
-END PGP SIGNATURE-



--
To UNSUBSCRIBE, email to debian-bugs-dist-requ...@lists.debian.org
with a subject of "unsubscribe". Trouble? Contact listmas...@lists.debian.org