From nigelsandever@btconnect.com

Created by nigelsandever@btconnect.com

The following snippet demonstrates a conflict between the :shared attribute and
lvalue subroutines.
Remove the :shared attribute from %things and the subject error goes away.

#! perl -slw
use strict;

package test;
use threads;
use threads​::shared;

my %things : shared;

sub new {
  my( $class, $thing ) = @​_;
  my $self = bless \$class, $class;
  $things{ $self } = $thing;
  return $self;
}

sub thing : lvalue {
  $things{ $_[ 0 ] };
}

sub DESTROY {
  delete $things{ $_[ 0 ] };
}

return 1 if caller;

package main;

my $test = test->new( '12345' );
print $test->thing;

$test->thing = 98765;
print $test->thing;

undef $test;
__END__
P​:\test>perl test.pm
12345
Can't return a temporary from lvalue subroutine at test.pm line 32.

Flags:
    category=core
    severity=medium

Site configuration information for perl v5.8.4:

Configured by ActiveState at Tue Jun  1 11:52:09 2004.

Summary of my perl5 (revision 5 version 8 subversion 4) configuration:
  Platform:
    osname=MSWin32, osvers=4.0, archname=MSWin32-x86-multi-thread
    uname=''
    config_args='undef'
    hint=recommended, useposix=true, d_sigaction=undef
    usethreads=undef use5005threads=undef useithreads=define 
usemultiplicity=define
    useperlio=define d_sfio=undef uselargefiles=define usesocks=undef
    use64bitint=undef use64bitall=undef uselongdouble=undef
    usemymalloc=n, bincompat5005=undef
  Compiler:
    cc='cl', ccflags ='-nologo -Gf -W3 -MD -Zi -DNDEBUG -O1 -DWIN32 -D_CONSOLE -
DNO_STRICT -DHAVE_DES_FCRYPT  -DNO_HASH_SEED -DPERL_IMPLICIT_CONTEXT -
DPERL_IMPLICIT_SYS -DUSE_PERLIO -DPERL_MSVCRT_READFIX',
    optimize='-MD -Zi -DNDEBUG -O1',
    cppflags='-DWIN32'
    ccversion='', gccversion='', gccosandvers=''
    intsize=4, longsize=4, ptrsize=4, doublesize=8, byteorder=1234
    d_longlong=undef, longlongsize=8, d_longdbl=define, longdblsize=10
    ivtype='long', ivsize=4, nvtype='double', nvsize=8, Off_t='__int64', 
lseeksize=8
    alignbytes=8, prototype=define
  Linker and Libraries:
    ld='link', ldflags ='-nologo -nodefaultlib -debug -opt:ref,icf  -libpath:"c:
\Perl\lib\CORE"  -machine:x86'
    libpth=C:\PROGRA~1\MICROS~3\VC98\lib
    libs=  oldnames.lib kernel32.lib user32.lib gdi32.lib winspool.lib  
comdlg32.lib advapi32.lib shell32.lib ole32.lib oleaut32.lib  netapi32.lib 
uuid.lib wsock32.lib mpr.lib winmm.lib  version.lib odbc32.lib odbccp32.lib 
msvcrt.lib
    perllibs=  oldnames.lib kernel32.lib user32.lib gdi32.lib winspool.lib  
comdlg32.lib advapi32.lib shell32.lib ole32.lib oleaut32.lib  netapi32.lib 
uuid.lib wsock32.lib mpr.lib winmm.lib  version.lib odbc32.lib odbccp32.lib 
msvcrt.lib
    libc=msvcrt.lib, so=dll, useshrplib=yes, libperl=perl58.lib
    gnulibc_version='undef'
  Dynamic Linking:
    dlsrc=dl_win32.xs, dlext=dll, d_dlsymun=undef, ccdlflags=' '
    cccdlflags=' ', lddlflags='-dll -nologo -nodefaultlib -debug -opt:ref,icf  -
libpath:"c:\Perl\lib\CORE"  -machine:x86'

Locally applied patches:
    ACTIVEPERL_LOCAL_PATCHES_ENTRY
    22751 Update to Test.pm 1.25
    21540 Fix backward-compatibility issues in if.pm


@INC for perl v5.8.4:
    C:/Perl/lib
    C:/Perl/site/lib
    .


Environment for perl v5.8.4:
    HOME (unset)
    LANG (unset)
    LANGUAGE (unset)
    LD_LIBRARY_PATH (unset)
    LOGDIR (unset)
    PATH=C:\Perl\bin\;C:\WINDOWS\system32;C:\WINDOWS;C:\WINDOWS\System32
\UnixTools;c:\perl584\bin;c:\perl561\bin;c:\perl581\bin;c:\perl561\bin;c:\cl;
    PERL_BADLANG (unset)
    SHELL (unset)

From @lizmat

At 7​:22 PM +0000 7/4/04, nigelsandever@​btconnect.com (via RT) wrote​:

# New Ticket Created by nigelsandever@​btconnect.com
# Please include the string​: [perl #30582]
# in the subject line of all future correspondence about this issue.
# <URL​: http​://rt.perl.org​:80/rt3/Ticket/Display.html?id=30582 >

This is a bug report for perl from nigelsandever@​btconnect.com,
generated with the help of perlbug 1.35 running under perl v5.8.4.

-----------------------------------------------------------------
[Please enter your report here]

The following snippet demonstrates a conflict between the :shared
attribute and
lvalue subroutines.

FWIW, it's the sharedness of the hash that's causing the problem, not
the attribute.

Remove the :shared attribute from %things and the subject error goes away.

#! perl -slw
use strict;

package test;
use threads;
use threads​::shared;

my %things : shared;

Replacing the above line with​:

my %things;
share( %things );

gives the same problem.

Liz

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

From @ysth

On Mon, Jul 05, 2004 at 09​:27​:52AM +0200, Elizabeth Mattijsen <liz@​dijkmat.nl> wrote​:

At 7​:22 PM +0000 7/4/04, nigelsandever@​btconnect.com (via RT) wrote​:

The following snippet demonstrates a conflict between the :shared
attribute and
lvalue subroutines.

FWIW, it's the sharedness of the hash that's causing the problem, not
the attribute.

Remove the :shared attribute from %things and the subject error goes away.

#! perl -slw
use strict;

package test;
use threads;
use threads​::shared;

my %things : shared;

Replacing the above line with​:

my %things;
share( %things );

gives the same problem.

Nothing to do with sharing; just magic​:

$ perl -MTie​::Hash -we'tie %x,"Tie​::StdHash"; sub foo​:lvalue {$x{foo}} foo=1'
Can't return a temporary from lvalue subroutine at -e line 1.

From @rgs

Fixed in bleadperl by :

Change 25194 on 2005/07/20 by rgs@​bloom

  Subject​: [PATCH] lvalue-subs returning elements of tied
hashes/arrays
  From​: Tassilo von Parseval <tassilo.von.parseval@​rwth-aachen.de>
  Date​: Wed, 20 Jul 2005 10​:43​:11 +0200
  Message-id​: <20050720084311.GA20332@​ethan>

@rgs - Status changed from 'open' to 'resolved'