Bug #46086 for MooseX-Singleton: "name used only once" warning from MX::Singleton

Thu May 14 15:41:44 2009 perl [...] evancarroll.com - Ticket created

Subject:

awkward warnings violation

Name "POE::Kernel::singleton" used only once: possible typo at /usr/local/share/perl/5.10.0/MooseX/Singleton/Meta/Class.pm line 53.

Thu May 14 15:45:16 2009 autarch [...] urth.org - Correspondence added

Subject:	Re: [rt.cpan.org #46086] awkward warnings violation
Date:	Thu, 14 May 2009 14:44:57 -0500 (CDT)
To:	Evan Carroll via RT <bug-MooseX-Singleton [...] rt.cpan.org>
From:	Dave Rolsky <autarch [...] urth.org>

On Thu, 14 May 2009, Evan Carroll via RT wrote: Show quoted text

> Thu May 14 15:41:44 2009: Request 46086 was acted upon. > Transaction: Ticket created by ECARROLL > Queue: MooseX-Singleton > Subject: awkward warnings violation > Broken in: (no value) > Severity: (no value) > Owner: Nobody > Requestors: perl@evancarroll.com > Status: new > Ticket <URL: https://rt.cpan.org/Ticket/Display.html?id=46086 > > > > Name "POE::Kernel::singleton" used only once: possible typo at > /usr/local/share/perl/5.10.0/MooseX/Singleton/Meta/Class.pm line 53.

Can you reproduce this without POE and submit a test? I think it's probably easy enough to fix. -dave /*============================================================ http://VegGuide.org http://blog.urth.org Your guide to all that's veg House Absolute(ly Pointless) ============================================================*/

Thu May 14 15:45:17 2009 The RT System itself - Status changed from 'new' to 'open'

Thu Dec 24 15:09:04 2009 DROLSKY [...] cpan.org - Status changed from 'open' to 'stalled'

Fri Jul 02 22:00:53 2010 mschwern [...] cpan.org - Correspondence added

I've hit this problem in some commercial code. It boils down to this: package Foo; use strict; use warnings; use MooseX::Singleton; Foo->_clear_instance; 1; Load that module and you'll get the warning. I'm not sure why the code in question finds it necessary to clear the instance on module load, its in a method called reset() and hdp wrote it. The fix is to add a "use warnings 'once'" to clear_singleton.

Fri Jul 02 22:01:00 2010 The RT System itself - Status changed from 'stalled' to 'open'

Fri Jul 02 22:02:02 2010 mschwern [...] cpan.org - Correspondence added

On Fri Jul 02 22:00:53 2010, MSCHWERN wrote: Show quoted text

> Load that module and you'll get the warning. I'm not sure why the code > in question finds it necessary to clear the instance on module load, its > in a method called reset() and hdp wrote it.

Code's open sourced now, though the history is truncated, if you want to puzzle it out. http://github.com/opensourcery/elementalClinic/blob/master/app/lib/eleMentalClinic/Config.pm

Fri Oct 15 06:28:58 2010 robin.ge [...] gmail.com - Correspondence added

From:

robin.ge [...] gmail.com

We have also had this issue, adding: no warnings 'once'; At line 24 "fixed" it, R

Mon Feb 21 03:08:27 2011 DROLSKY [...] cpan.org - Subject changed from 'awkward warnings violation' to '"name used only once" warning from MX::Singleton'

Fri Feb 25 09:34:29 2011 chisel [...] chizography.net - Correspondence added

On Fri Oct 15 11:28:58 2010, robinedwards wrote: Show quoted text

> We have also had this issue, > > adding: > > no warnings 'once'; > > At line 24 "fixed" it, > > R

This is the fix I made for the same issue. no strict 'refs'; no warnings 'once'; return ${"$pkg\::singleton"} = super;

Fri Feb 25 10:24:32 2011 autarch [...] urth.org - Correspondence added

Subject:	Re: [rt.cpan.org #46086] "name used only once" warning from MX::Singleton
Date:	Fri, 25 Feb 2011 09:24:22 -0600 (CST)
To:	Chisel Wright via RT <bug-MooseX-Singleton [...] rt.cpan.org>
From:	Dave Rolsky <autarch [...] urth.org>

On Fri, 25 Feb 2011, Chisel Wright via RT wrote: Show quoted text

> Queue: MooseX-Singleton > Ticket <URL: https://rt.cpan.org/Ticket/Display.html?id=46086 > > > On Fri Oct 15 11:28:58 2010, robinedwards wrote:

>> We have also had this issue, >> >> adding: >> >> no warnings 'once'; >> >> At line 24 "fixed" it, >> >> R

> > This is the fix I made for the same issue. > > no strict 'refs'; > no warnings 'once'; > return ${"$pkg\::singleton"} = super;

I don't suppose you have a test case? -dave /*============================================================ http://VegGuide.org http://blog.urth.org Your guide to all that's veg House Absolute(ly Pointless) ============================================================*/

Wed Apr 20 23:10:42 2011 zwon [...] trinitum.org - Correspondence added

This one fails for me both with Moose-1.25 and Moose-2.0000 on MooseX::Singleton 0.26 -- Pavel Shaydo

Subject:

warning_once.t

use Test::More qw(no_plan); use Test::NoWarnings; BEGIN { package Singleton; use MooseX::Singleton; has attribute => (is => 'rw'); sub BUILD { shift->attribute(1); } } BEGIN { Singleton->initialize } my $s = Singleton->instance; ok $s->attribute, "Attribute is set";

Sat Jul 02 09:57:06 2011 jquelin [...] cpan.org - Cc JQUELIN added

Tue Nov 22 06:13:01 2011 chisel [...] chizography.net - Correspondence added 45 min

On Fri Feb 25 15:24:32 2011, autarch@urth.org wrote: Show quoted text

> I don't suppose you have a test case? >

Sorry - I don't know how I missed this response. My test is very similar to the last comment in the thread. For some reason 'override _construct_instance => sub { ... }' seems overly sensitive to 'once' warnings where 'sub clear_singleton' isn't. I've attached a patch and a test that should fail until the patch is applied. This was written and tested against: $MooseX::Singleton::Role::Meta::Class::VERSION = '0.27';

Subject:

warnings_once.patch

--- /tmp/Meta-Class.pm.original 2011-11-21 17:57:36.000000000 +0000 +++ /opt/xt/xt-perl/lib/site_perl/5.14.2/MooseX/Singleton/Role/Meta/Class.pm 2011-11-21 17:57:39.000000000 +0000 @@ -40,6 +40,7 @@ my $pkg = $class->name; no strict 'refs'; + no warnings 'once'; return ${"$pkg\::singleton"} = super; };

Subject:

warnings_once.t

# test script for: https://rt.cpan.org/Ticket/Display.html?id=46086 use Test::More qw(no_plan); use Test::NoWarnings; BEGIN { package OnlyUsedOnce; use strict; use warnings; use MooseX::Singleton; } BEGIN { OnlyUsedOnce->initialize; } my $s = OnlyUsedOnce->instance;

Sun Nov 27 05:32:36 2011 KAARE [...] cpan.org - Correspondence added

Show quoted text

> My test is very similar to the last comment in the thread.

Fixed in HEAD http://git.shadowcat.co.uk/gitweb/gitweb.cgi?p=gitmo/MooseX-Singleton.git;a=commit;h=0f22810a8a14902c7724ea80a9951829e42ac8eb

Sun Nov 27 05:32:44 2011 KAARE [...] cpan.org - Status changed from 'open' to 'resolved'