[perl #117983] !( /\G(?=X)/gc && /\G(?=X)/gc )

# New Ticket Created by  Barrie Slaymaker 
# Please include the string:  [perl #117983]
# in the subject line of all future correspondence about this issue. 
# <URL: https://rt.perl.org:443/rt3/Ticket/Display.html?id=117983 >


This is a bug report for perl from barries@slaysys.com,
generated with the help of perlbug 1.39 running under perl 5.12.3.

     # It seems like all tests should pass, but I get:
     #
     #     ok 1 - no match, no pos
     #     not ok 2 - match, no pos
     #     #   Failed test 'match, no pos'
     #     #   at foo.pl line 34.
     #     ok 3 - no match, pos
     #     ok 4 - match, pos

     use Test::More;

     for my $m (0..3) {
         my $test_name = join ", ",
             $m & 1 ? "match" : "no match",
             $m & 2 ? "pos"   : "no pos";

         $_ = 'X';

         # This next line seems like it should not affect
         # the test results because it is a 0 width assertion
         # that matches succesfully. However, executing the
         # match causes the final match below to fail.
         m{\G(?=X)}gc if $m & 1;

         my $pos_a = pos;

         # This next line seems like it should have no effect,
         # but executing the assignment allows fourth test to pass.
         pos($_) = pos($_) if $m & 2;

         die "BUG: pos() changed" unless (pos // "") eq ($pos_a // "");

         my $result = m{\G(?=X)}gc; # This should always match

         ok $result, $test_name;
     }


---
Flags:
     category=core
     severity=medium
---
Site configuration information for perl 5.12.3:

Configured by 1 at Sun May 15 16:53:01 2011.

Summary of my perl5 (revision 5 version 12 subversion 3) configuration:

   Platform:
     osname=MSWin32, osvers=5.1, archname=MSWin32-x86-multi-thread
     uname='Win32 strawberryperl 5.12.3.0 #1 Sun May 15 09:44:53 2011 i386'
     config_args='undef'
     hint=recommended, useposix=true, d_sigaction=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='gcc', ccflags =' -s -O2 -DWIN32 -DHAVE_DES_FCRYPT  
-DUSE_SITECUSTOMIZE -DPERL_IMPLICIT_CONTEXT -DPERL_IMPLICIT_SYS 
-fno-strict-aliasing -mms-bitfields -DPERL_MSVCRT_READFIX',
     optimize='-s -O2',
     cppflags='-DWIN32'
     ccversion='', gccversion='4.4.3', gccosandvers=''
     intsize=4, longsize=4, ptrsize=4, doublesize=8, byteorder=1234
     d_longlong=undef, longlongsize=8, d_longdbl=define, longdblsize=12
     ivtype='long', ivsize=4, nvtype='double', nvsize=8, Off_t='long 
long', lseeksize=8
     alignbytes=8, prototype=define
   Linker and Libraries:
     ld='g++', ldflags ='-s -L"C:\strawberry\perl\lib\CORE" 
-L"C:\strawberry\c\lib"'
     libpth=C:\strawberry\c\lib C:\strawberry\c\i686-w64-mingw32\lib
     libs=-lmoldname -lkernel32 -luser32 -lgdi32 -lwinspool -lcomdlg32 
-ladvapi32 -lshell32 -lole32 -loleaut32 -lnetapi32 -luuid -lws2_32 -lmpr 
-lwinmm -lversion -lodbc32 -lodbccp32 -lcomctl32
     perllibs=-lmoldname -lkernel32 -luser32 -lgdi32 -lwinspool 
-lcomdlg32 -ladvapi32 -lshell32 -lole32 -loleaut32 -lnetapi32 -luuid 
-lws2_32 -lmpr -lwinmm -lversion -lodbc32 -lodbccp32 -lcomctl32
     libc=, so=dll, useshrplib=true, libperl=libperl512.a
     gnulibc_version=''
   Dynamic Linking:
     dlsrc=dl_win32.xs, dlext=dll, d_dlsymun=undef, ccdlflags=' '
     cccdlflags=' ', lddlflags='-mdll -s -L"C:\strawberry\perl\lib\CORE" 
-L"C:\strawberry\c\lib"'

Locally applied patches:


---
@INC for perl 5.12.3:
     C:\SlaySys\angular_test\lib
     C:/strawberry/perl/site/lib
     C:/strawberry/perl/vendor/lib
     C:/strawberry/perl/lib
     .

---
Environment for perl 5.12.3:
     HOME (unset)
     LANG (unset)
     LANGUAGE (unset)
     LD_LIBRARY_PATH (unset)
     LOGDIR (unset)
     PATH=C:\Program Files\Common Files\Microsoft Shared\Windows 
Live;C:\Perl\bin\;c:\bin;c:/MinGW/msys/1.0/bin;c:\MinGW\bin;C:\WINDOWS\system32;C:\WINDOWS;C:\WINDOWS\System32\Wbem;c:\bin;C:\Program 
Files\Perforce; c:\Program Files\vim;C:\Program 
Files\Perforce\;c:\Program Files\Beyond Compare 3;C:\Program 
Files\SciTools/bin/pc-win32;C:\strawberry\c\bin;C:\strawberry\perl\site\bin;C:\strawberry\perl\bin;c:\Program 
Files\Common Files\HP\Digital Imaging\bin;c:\Program Files\HP\Digital 
Imaging\bin\;c:\Program Files\HP\Digital Imaging\bin\Qt\Qt 
4.3.3;C:\Program Files\Common Files\Microsoft Shared\Windows 
Live;c:\Program Files\R\R-2.15.2\bin
     PERL5LIB=C:\SlaySys\angular_test\lib
     PERL_BADLANG (unset)
     PERL_JSON_BACKEND=JSON::XS
     PERL_YAML_BACKEND=YAML
     SHELL (unset)

• [perl #117983] !( /\G(?=X)/gc && /\G(?=X)/gc ) by Barrie Slaymaker
• Re: [perl #117983] !( /\G(?=X)/gc && /\G(?=X)/gc ) by Lukas Mai
• [perl #117983] !( /\G(?=X)/gc && /\G(?=X)/gc ) by Barrie Slaymaker via RT
• Re: [perl #117983] !( /\G(?=X)/gc && /\G(?=X)/gc ) by Barrie Slaymaker