[perl #24176] inconsistent m/.../g behaviour

# New Ticket Created by  Jonathan Eisler 
# Please include the string:  [perl #24176]
# in the subject line of all future correspondence about this issue. 
# <URL: http://rt.perl.org/rt2/Ticket/Display.html?id=24176 >


This is a bug report for perl from johny@rift.com,
generated with the help of perlbug 1.26 running under perl 5.00503.


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[Please enter your report here]
I think this is a bug, but it may just be strange behaviour: global
matching (ie: m/.../g ) behaves differently when the extracted results are
saved to lexical variables or when the $1, $2, etc, implicit variables are
used.

Consider:

my $text = "Foo\nBar\n";
while ( $text =~ /(\w+)/g ) { print $1, "\n" }

The above script prints 2 lines to standard out, as expected:
"Foo\nBar\n".

Now consider:

my $text = "Foo\nBar\n";
while ( my ( $name ) = ( $text =~ /(\w+)/g ) ) { print $name, "\n" }

The above script goes into an infinite loop, printing "Foo\n" to stdout
over and over.

Shouldn't the two scripts behave equivalently?

Note, I've tested this on:
	perl 5.00503 for freebsd
	perl 5.8.1 for linux
	perl 5.8.0 for darwin
I get the same behaviour on all 3.

[Please do not change anything below this line]
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---
Site configuration information for perl 5.00503:

Configured by markm at Sun Mar  5 13:39:27 SAST 2000.

Summary of my perl5 (5.0 patchlevel 5 subversion 3) configuration:
  Platform:
    osname=freebsd, osvers=4.0-current, archname=i386-freebsd
    uname='FreeBSD freefall.FreeBSD.org 4.0-current FreeBSD 4.0-current #0: $Date$'
    hint=recommended, useposix=true, d_sigaction=define
    usethreads=undef useperlio=undef d_sfio=undef
  Compiler:
    cc='cc', optimize='undef', gccversion=2.95.2 19991024 (release)
    cppflags=''
    ccflags =''
    stdchar='char', d_stdstdio=undef, usevfork=true
    intsize=4, longsize=4, ptrsize=4, doublesize=8
    d_longlong=define, longlongsize=8, d_longdbl=define, longdblsize=12
    alignbytes=4, usemymalloc=n, prototype=define
  Linker and Libraries:
    ld='cc', ldflags ='-Wl,-E -lperl -lm '
    libpth=/usr/lib
    libs=-lm -lc -lcrypt
    libc=, so=so, useshrplib=true, libperl=libperl.so.3
  Dynamic Linking:
    dlsrc=dl_dlopen.xs, dlext=so, d_dlsymun=undef, ccdlflags=' -Wl,-R/usr/lib'
    cccdlflags='-DPIC -fpic', lddlflags='-Wl,-E -shared -lperl -lm '

Locally applied patches:


---
@INC for perl 5.00503:
    /usr/libdata/perl/5.00503/mach
    /usr/libdata/perl/5.00503
    /usr/local/lib/perl5/site_perl/5.005/i386-freebsd
    /usr/local/lib/perl5/site_perl/5.005
    .

---
Environment for perl 5.00503:
    HOME=/usr/home/johny
    LANG (unset)
    LANGUAGE (unset)
    LD_LIBRARY_PATH (unset)
    LOGDIR (unset)
    PATH=/sbin:/bin:/usr/sbin:/usr/bin:/usr/games:/usr/local/bin:/usr/X11R6/bin:/usr/home/johny
    PERL_BADLANG (unset)
    SHELL=/usr/local/bin/tcsh

• [perl #24176] inconsistent m/.../g behaviour by Jonathan Eisler
• Re: [perl #24176] inconsistent m/.../g behaviour by Andreas J Koenig
• Re: [perl #24176] inconsistent m/.../g behaviour by Graham Barr
• Re: [perl #24176] inconsistent m/.../g behaviour by Yitzchak Scott-Thoennes