From wesley.spikes@dreamhost.com

Created by wesley.spikes@dreamhost.com

Using SelectSaver+IO​::Scalar in one line causes perl to error with​:

  Can't call method "PRINT" on an undefined value at
  p5p-XJJCDNvk.pl line 11.

The below test case WORKS on 5.10.1, and FAILS on both Perl 5.16.3
and Perl 5.18.2. Other versions have not been tried.

This is boiled down from a real world use case where this change in
behavior is breaking a production application.

We have a workaround where we store the IO​::Scalar object and the
SelectSaver object in a stash in a wrapper object.

Test case​:

----
# http​://pastebin.com/XJJCDNvk
use strict;
use warnings;

use IO​::Scalar;
use SelectSaver;

print "Before\n";
my $out = '';
{
  my $Saver = SelectSaver->new(IO​::Scalar->new(\$out));
  print "Middle\n";
};
print "After\n";
print "out is $out\n";
----

Flags:
    category=library
    severity=medium
    module=SelectSaver

Site configuration information for perl 5.16.3:

Configured by cgranum at Wed Jan 22 09:22:45 PST 2014.

Summary of my perl5 (revision 5 version 16 subversion 3) configuration:
   
  Platform:
    osname=linux, osvers=2.6.32.8-grsec-2.1.14-modsign-xeon-64, archname=x86_64-linux
    uname='linux fubar 2.6.32.8-grsec-2.1.14-modsign-xeon-64 #2 smp sat mar 13 00:42:43 pst 2010 x86_64 gnulinux '
    config_args='-de -Dprefix=/opt/plack/perl -Accflags=-fPIC'
    hint=recommended, useposix=true, d_sigaction=define
    useithreads=undef, usemultiplicity=undef
    useperlio=define, d_sfio=undef, uselargefiles=define, usesocks=undef
    use64bitint=define, use64bitall=define, uselongdouble=undef
    usemymalloc=n, bincompat5005=undef
  Compiler:
    cc='cc', ccflags ='-fPIC -fno-strict-aliasing -pipe -fstack-protector -I/usr/local/include -D_LARGEFILE_SOURCE -D_FILE_OFFSET_BITS=64',
    optimize='-O2',
    cppflags='-fPIC -fno-strict-aliasing -pipe -fstack-protector -I/usr/local/include'
    ccversion='', gccversion='4.3.2', gccosandvers=''
    intsize=4, longsize=8, ptrsize=8, doublesize=8, byteorder=12345678
    d_longlong=define, longlongsize=8, d_longdbl=define, longdblsize=16
    ivtype='long', ivsize=8, nvtype='double', nvsize=8, Off_t='off_t', lseeksize=8
    alignbytes=8, prototype=define
  Linker and Libraries:
    ld='cc', ldflags =' -fstack-protector -L/usr/local/lib'
    libpth=/usr/local/lib /lib/../lib /usr/lib/../lib /lib /usr/lib /lib64 /usr/lib64
    libs=-lnsl -lgdbm -ldl -lm -lcrypt -lutil -lc -lgdbm_compat
    perllibs=-lnsl -ldl -lm -lcrypt -lutil -lc
    libc=/lib/libc-2.7.so, so=so, useshrplib=false, libperl=libperl.a
    gnulibc_version='2.7'
  Dynamic Linking:
    dlsrc=dl_dlopen.xs, dlext=so, d_dlsymun=undef, ccdlflags='-Wl,-E'
    cccdlflags='-fPIC', lddlflags='-shared -O2 -L/usr/local/lib -fstack-protector'

Locally applied patches:
    


@INC for perl 5.16.3:
    /opt/plack/perl/lib/site_perl/5.16.3/x86_64-linux
    /opt/plack/perl/lib/site_perl/5.16.3
    /opt/plack/perl/lib/5.16.3/x86_64-linux
    /opt/plack/perl/lib/5.16.3
    .


Environment for perl 5.16.3:
    HOME=/home/wesleys
    LANG=en_US.UTF-8
    LANGUAGE (unset)
    LC_COLLATE=C
    LD_LIBRARY_PATH (unset)
    LOGDIR (unset)
    PATH=/home/wesleys/local/bin:/dh/bin:/home/wesleys/local/bin:/home/wesleys/bin:/home/wesleys/.gems/bin:/usr/lib/ruby/gems/1.8/bin/:/usr/local/bin:/usr/bin:/bin:/usr/bin/X11:/usr/games
    PERL_BADLANG (unset)
    SHELL=/bin/bash

From @iabyn

On Mon, Feb 03, 2014 at 03​:08​:12PM -0800, via RT wrote​:

# New Ticket Created by
# Please include the string​: [perl #121158]
# in the subject line of all future correspondence about this issue.
# <URL​: https://rt-archive.perl.org/perl5/Ticket/Display.html?id=121158 >

This is a bug report for perl from wesley.spikes@​dreamhost.com,
generated with the help of perlbug 1.39 running under perl 5.16.3.

-----------------------------------------------------------------
[Please describe your issue here]

Using SelectSaver+IO​::Scalar in one line causes perl to error with​:

Can't call method "PRINT" on an undefined value at
p5p\-XJJCDNvk\.pl line 11\.

The below test case WORKS on 5.10.1, and FAILS on both Perl 5.16.3
and Perl 5.18.2. Other versions have not been tried.

This is boiled down from a real world use case where this change in
behavior is breaking a production application.

We have a workaround where we store the IO​::Scalar object and the
SelectSaver object in a stash in a wrapper object.

Test case​:

----
# http​://pastebin.com/XJJCDNvk
use strict;
use warnings;

use IO​::Scalar;
use SelectSaver;

print "Before\n";
my $out = '';
{
my $Saver = SelectSaver->new(IO​::Scalar->new(\$out));
print "Middle\n";
};
print "After\n";
print "out is $out\n";

It bisects to the following change. I don't know whether it's perl or one
of the modules at fault.

commit 2acc331
Author​: Father Chrysostomos <sprout@​cpan.org>
Date​: Sun Oct 24 15​:50​:23 2010 -0700

  [perl #77810] Scalars vs globs
 
  Stop *{} from returning globs with the SVf_FAKE flag on.
 
  It removes three tests from t/op/gv.t (that I added) that test buggy
  edge cases that can no longer occur.
 
  It also modifies tests in t/io/defout.t to keep them passing. I am not
  sure that test script serves any purpose any more.

--
I before E. Except when it isn't.

The RT System itself - Status changed from 'new' to 'open'