Infinite recursion error with closures

# New Ticket Created by  "Zsbán Ambrus" 
# Please include the string:  [perl #42255]
# in the subject line of all future correspondence about
this issue. 
# <URL: h
ttp://rt.perl.org/rt3/Ticket/Display.html?id=42255 >


This is a bug report for perl from ambrusmath.bme.hu,
generated with the help of perlbug 1.35 running under perl
v5.8.8.


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


The following program falls into an infinite recursion with
the warning
"Deep recursion on anonymous subroutine at alapm.pl
line 17."  When,
however, you uncomment the line marked with an arrow, it
will do what I
think is the correct behaiviour: the program exits without
doing anything.


#!perl
# alapm.pl -- reduced example for a possible interpreter
bug
# by ambrus

use warnings;
use strict;

sub poss {
	my($v, $f) = _;
	if ($v) {
		&$f();
	} else {
		my(vv2) = ();
		poss(1, sub {
			#my $fwr_unused = $f; # <----
			for my $k (0 .. vv2) {
				&{sub { &$f() }}();
			}
		});
	}
}

poss(0, sub {});

__END__


I cannot see how uncommenting that line could make any
difference.

Kudos to pKai by helping me pinpoint the bug.

Thanks,

Ambrus


[Please do not change anything below this line]
------------------------------------------------------------
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---
Flags:
    category=core
    severity=low
---
Site configuration information for perl v5.8.8:

Configured by ambrus at Mon May 22 23:16:27 CEST 2006.

Summary of my perl5 (revision 5 version 8 subversion 8)
configuration:
  Platform:
    osname=linux, osvers=2.4.27-3-686, archname=i686-linux
    uname='linux king 2.4.27-3-686 #1 wed feb 8 12:40:33 utc
2006 i686
gnulinux '
    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 -pipe
-I/usr/local/include
-D_LARGEFILE_SOURCE -D_FILE_OFFSET_BITS=64',
    optimize='-O2',
    cppflags='-fno-strict-aliasing -pipe
-I/usr/local/include'
    ccversion='', gccversion='3.3.5 (Debian 1:3.3.5-13)',
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 -ldl -lm -lcrypt -lutil -lc
    perllibs=-lnsl -ldl -lm -lcrypt -lutil -lc
    libc=/lib/libc-2.3.2.so, so=so, useshrplib=false,
libperl=libperl.a
    gnulibc_version='2.3.2'
  Dynamic Linking:
    dlsrc=dl_dlopen.xs, dlext=so, d_dlsymun=undef,
ccdlflags='-Wl,-E'
    cccdlflags='-fpic', lddlflags='-shared
-L/usr/local/lib'

Locally applied patches:


---
INC
for perl v5.8.8:
    /usr/local/lib/perl5/5.8.8/i686-linux
    /usr/local/lib/perl5/5.8.8
    /usr/local/lib/perl5/site_perl/5.8.8/i686-linux
    /usr/local/lib/perl5/site_perl/5.8.8
    /usr/local/lib/perl5/site_perl
    .

---
Environment for perl v5.8.8:
    HOME=/home/ambrus
    LANG (unset)
    LANGUAGE=en_HU:en_US:en_GB:en
    LC_CTYPE=hu_HU
    LD_LIBRARY_PATH (unset)
    LOGDIR (unset)
   
PATH=/home/ambrus/local/bin:/usr/local/bin:/usr/bin:/bin:/us
r/bin/X11:/usr/games
    PERL_BADLANG (unset)
    SHELL=/bin/bash

On Sat, Mar 31, 2007 at 06:41:43AM -0700, Zsbán Ambrus
wrote:
> The following program falls into an infinite recursion
with the warning
> "Deep recursion on anonymous subroutine at
alapm.pl line 17."  When,
> however, you uncomment the line marked with an arrow,
it will do what I
> think is the correct behaiviour: the program exits
without doing anything.
> 
> 
> #!perl
> # alapm.pl -- reduced example for a possible
interpreter bug
> # by ambrus
> 
> use warnings;
> use strict;
> 
> sub poss {
> 	my($v, $f) = _;
> 	if ($v) {
> 		&$f();
> 	} else {
> 		my(vv2) = ();
> 		poss(1, sub {
> 			#my $fwr_unused = $f; # <----
> 			for my $k (0 .. vv2) {
> 				&{sub { &$f() }}();
> 			}
> 		});
> 	}
> }
> 
> poss(0, sub {});

Thanks for the report. This issue has been fixed in the
development branch
of perl, from 5.9.0 onwards.

-- 
"The GPL violates the U.S. Constitution, together with
copyright,
antitrust and export control laws"
    -- SCO smoking crack again.