[perl #24881] Closure/lexical inconsistency

# New Ticket Created by  Tassilo v. Parseval 
# Please include the string:  [perl #24881]
# in the subject line of all future correspondence about this issue. 
# <URL: http://rt.perl.org/rt3/Ticket/Display.html?id=24881 >



This is a bug report for perl from tassilo.parseval@post.rwth-aachen.de,
generated with the help of perlbug 1.34 running under perl v5.8.2.


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[Please enter your report here]

Consider this code that expectedly does the wrong thing:

    {
        my $d = 'xxx';
        sub foo {
            my ($b, $c);
            $b = '$d';
            $c = eval("\"$b\"");
            print "$c\n";
        }
    }
    foo();

No problem here: Perl doesn't see that foo() contains a hidden reference to $d and so
the garbage collector has already cleaned up $d when foo() is called.

But what about this here:

    {
        my $d;
        sub foo {
            my ($b, $c);
            $b = '$d';
            $c = eval("\"$b\"");
            print "$c\n";
        }
        sub bar {
            $d = 'xxx';
            foo();
        }
    }
    bar();

In my understanding, the mentioning of $d in bar should keep $d alive by the
time foo() is called.

I am not sure, whether this is a known issue.

[Please do not change anything below this line]
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---
Flags:
    category=core
    severity=low
---
Site configuration information for perl v5.8.2:

Configured by root at Fri Nov 14 07:29:04 UTC 2003.

Summary of my perl5 (revision 5.0 version 8 subversion 2) configuration:
  Platform:
    osname=linux, osvers=2.4.21, archname=i686-linux
    uname='linux ethan 2.4.21 #3 tue nov 11 09:22:00 utc 2003 i686 unknown '
    config_args=''
    hint=recommended, useposix=true, d_sigaction=define
    usethreads=undef use5005threads=undef useithreads=undef usemultiplicity=undef
    useperlio=define d_sfio=undef uselargefiles=define usesocks=undef
    use64bitint=undef use64bitall=undef uselongdouble=undef
    usemymalloc=n, bincompat5005=undef
  Compiler:
    cc='cc', ccflags ='-fno-strict-aliasing -D_LARGEFILE_SOURCE -D_FILE_OFFSET_BITS=64',
    optimize='-O3 -march=athlon -fomit-frame-pointer -foptimize-sibling-calls -finline-functions -fstrength-reduce -frerun-loop-opt -fexpensive-optimizations -fprefetch-loop-arrays -fmove-all-movables',
    cppflags='-fno-strict-aliasing'
    ccversion='', gccversion='3.2', gccosandvers=''
    intsize=4, longsize=4, ptrsize=4, doublesize=8, byteorder=1234
    d_longlong=define, longlongsize=8, d_longdbl=define, longdblsize=12
    ivtype='long', ivsize=4, nvtype='double', nvsize=8, Off_t='off_t', lseeksize=8
    alignbytes=4, prototype=define
  Linker and Libraries:
    ld='cc', ldflags =' -L/usr/local/lib'
    libpth=/usr/local/lib /lib /usr/lib
    libs=-lnsl -ldb -ldl -lm -lcrypt -lutil -lc
    perllibs=-lnsl -ldl -lm -lcrypt -lutil -lc
    libc=/lib/libc-2.2.5.so, so=so, useshrplib=false, libperl=libperl.a
    gnulibc_version='2.2.5'
  Dynamic Linking:
    dlsrc=dl_dlopen.xs, dlext=so, d_dlsymun=undef, ccdlflags='-rdynamic'
    cccdlflags='-fpic', lddlflags='-shared -L/usr/local/lib'

Locally applied patches:
    

---
@INC for perl v5.8.2:
    /usr/opt/perl5.8.2/lib/5.8.2/i686-linux
    /usr/opt/perl5.8.2/lib/5.8.2
    /usr/opt/perl5.8.2/lib/site_perl/5.8.2/i686-linux
    /usr/opt/perl5.8.2/lib/site_perl/5.8.2
    /usr/opt/perl5.8.2/lib/site_perl
    .

---
Environment for perl v5.8.2:
    HOME=/home/ethan
    LANG=C
    LANGUAGE (unset)
    LC_CTYPE=de_DE@euro
    LD_LIBRARY_PATH=:/usr/local/j2sdk1.4.0/jre/lib/i386:/usr/local/pwlib/lib:/usr/local/lib
    LOGDIR (unset)
    PATH=/usr/local/bin:/usr/bin:/bin:/usr/X11R6/bin:/usr/games:/usr/local/j2re1.4.1/bin:/usr/local/mpich-1.2.5/ch_p4/bin
    PERLDOC_PAGER=/bin/less -isR
    PERL_BADLANG (unset)
    SHELL=/bin/bash

• Re: [perl #24881] Closure/lexical inconsistency by Tassilo von Parseval
• [perl #24881] Closure/lexical inconsistency by perlbug-followup
• Re: [perl #24881] Closure/lexical inconsistency by Glenn Linderman