[perl #68308] [PATCH] String with NULL auto-increment bug fix

# New Ticket Created by  Bo Borgerson 
# Please include the string:  [perl #68308]
# in the subject line of all future correspondence about this issue. 
# <URL: http://rt.perl.org/rt3/Ticket/Display.html?id=68308 >


This is a bug report for perl from gigabo@gmail.com,
generated with the help of perlbug 1.36 running under perl 5.10.0.


-----------------------------------------------------------------

Hi,

I recently noticed an inconsistency in Perl's auto-increment op for 
strings containing NULL bytes.

For strings matching /^([a-zA-Z]*[0-9]*)([^0-9])/ where $1 is
non-empty Perl's behavior is to "magically" auto-increment $1.  This
behavior does not hold when $2 is NULL ("\0").

I tracked this down to an assumption of NULL-termination in the
Perl_sv_inc function in sv.c.  In the attached patch I just changed the
conditional to test offset from beginning of buffer against SvCUR instead.

I've observed this inconsistency in v5.8.4, v5.10.0 and a fresh pull of 
git://perl5.git.perl.org/perl.git (against which the patch was created).

The patch also includes a test case.

Thanks,

Bo

-----------------------------------------------------------------
---
Flags:
     category=core
     severity=low
---
Site configuration information for perl 5.10.0:

Configured by Debian Project at Fri Jun 26 18:39:52 UTC 2009.

Summary of my perl5 (revision 5 version 10 subversion 0) configuration:
   Platform:
     osname=linux, osvers=2.6.24-23-server, 
archname=x86_64-linux-gnu-thread-multi
     uname='linux crested 2.6.24-23-server #1 smp wed apr 1 22:14:30 utc 
2009 x86_64 gnulinux '
     config_args='-Dusethreads -Duselargefiles -Dccflags=-DDEBIAN 
-Dcccdlflags=-fPIC -Darchname=x86_64-linux-gnu -Dprefix=/usr 
-Dprivlib=/usr/share/perl/5.10 -Darchlib=/usr/lib/perl/5.10 
-Dvendorprefix=/usr -Dvendorlib=/usr/share/perl5 
-Dvendorarch=/usr/lib/perl5 -Dsiteprefix=/usr/local 
-Dsitelib=/usr/local/share/perl/5.10.0 
-Dsitearch=/usr/local/lib/perl/5.10.0 -Dman1dir=/usr/share/man/man1 
-Dman3dir=/usr/share/man/man3 -Dsiteman1dir=/usr/local/man/man1 
-Dsiteman3dir=/usr/local/man/man3 -Dman1ext=1 -Dman3ext=3perl 
-Dpager=/usr/bin/sensible-pager -Uafs -Ud_csh -Ud_ualarm -Uusesfio 
-Uusenm -DDEBUGGING=-g -Doptimize=-O2 -Duseshrplib 
-Dlibperl=libperl.so.5.10.0 -Dd_dosuid -des'
     hint=recommended, useposix=true, d_sigaction=define
     useithreads=define, usemultiplicity=define
     useperlio=define, d_sfio=undef, uselargefiles=define, usesocks=undef
     use64bitint=define, use64bitall=define, uselongdouble=undef
     usemymalloc=n, bincompat5005=undef
   Compiler:
     cc='cc', ccflags ='-D_REENTRANT -D_GNU_SOURCE -DDEBIAN 
-fno-strict-aliasing -pipe -I/usr/local/include -D_LARGEFILE_SOURCE 
-D_FILE_OFFSET_BITS=64',
     optimize='-O2 -g',
     cppflags='-D_REENTRANT -D_GNU_SOURCE -DDEBIAN -fno-strict-aliasing 
-pipe -I/usr/local/include'
     ccversion='', gccversion='4.3.3', gccosandvers=''
     intsize=4, longsize=8, ptrsize=8, doublesize=8, byteorder=12345678
     d_longlong=define, longlongsize=8, d_longdbl=define, longdblsize=16
     ivtype='long', ivsize=8, nvtype='double', nvsize=8, Off_t='off_t', 
lseeksize=8
     alignbytes=8, prototype=define
   Linker and Libraries:
     ld='cc', ldflags =' -L/usr/local/lib'
     libpth=/usr/local/lib /lib /usr/lib /lib64 /usr/lib64
     libs=-lgdbm -lgdbm_compat -ldb -ldl -lm -lpthread -lc -lcrypt
     perllibs=-ldl -lm -lpthread -lc -lcrypt
     libc=/lib/libc-2.9.so, so=so, useshrplib=true, 
libperl=libperl.so.5.10.0
     gnulibc_version='2.9'
   Dynamic Linking:
     dlsrc=dl_dlopen.xs, dlext=so, d_dlsymun=undef, ccdlflags='-Wl,-E'
     cccdlflags='-fPIC', lddlflags='-shared -O2 -g -L/usr/local/lib'

Locally applied patches:


---
@INC for perl 5.10.0:
     /etc/perl
     /usr/local/lib/perl/5.10.0
     /usr/local/share/perl/5.10.0
     /usr/lib/perl5
     /usr/share/perl5
     /usr/lib/perl/5.10
     /usr/share/perl/5.10
     /usr/local/lib/site_perl
     .

---
Environment for perl 5.10.0:
     HOME=/home/bo
     LANG=en_US.UTF-8
     LANGUAGE (unset)
     LD_LIBRARY_PATH=/usr/lib/mozilla-firefox:
     LOGDIR (unset)
 
PATH=/home/bo/bin:/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin:/usr/games:/home/bo/bin:/home/bo/bin
     PERL_BADLANG (unset)
     SHELL=/bin/bash

• [perl #68308] [PATCH] String with NULL auto-increment bug fix by Bo Borgerson