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Postings from April 2007
On Apr 19 2007, Nicholas Clark wrote:
> On Thu, Apr 19, 2007 at 10:05:30AM +0200, Rafael Garcia-Suarez wrote:
> > On 18/04/07, via RT Colin Robertson <perlbug-followup@perl.org> wrote:
> > >Running "perl -we 'use Once;'" gives us no warnings, but running "perl
> > >-we 'use Once; use Twice;'" gives us:
> > >
> > >Subroutine Twice::foobar redefined at
> > >/usr/local/lib/perl5/5.8.7/Exporter.pm line 65.
> > > at Twice.pm line 4
> > >
> > >Ideally, there should have been a warning just when compiling Once.
> >
> > I get a warning with only Once.pm with perl 5.8.8 (and also bleadperl
> > and peprl 5.6.2). Not sure what has changed since 5.8.7...
>
> It might be this one. From perl588delta.pod:
>
> =head2 no warnings 'category' works correctly with -w
>
> Previously when running with warnings enabled globally via C<-w>, selective
> disabling of specific warning categories would actually turn off all warnings.
> This is now fixed; now C<no warnings 'io';> will only turn off warnings in the
> C<io> class. Previously it would erroneously turn off all warnings.
>
> This bug fix may cause some programs to start correctly issuing warnings.
>
> =cut
That seems pretty likely, since Carp::Heavy (ultimately loaded by
Exporter) has a C<no warnings "once";> in it. I believe the workaround
for this in older perls is to make sure to use warnings before anything
else. So for Colin's test, try
perl -we 'use warnings; use Once;'
And for the in-the-wild case:
use warnings;
use File::Slurp;
use File::Temp;
--
Rick Delaney
rick@bort.ca
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