From @khwilliamson

This is a bug report for perl from public@​khwilliamson.com,
generated with the help of perlbug 1.39 running under perl 5.14.0.

If a bracketed character class includes a character that has a
multi-char fold, and it also includes the first character of that fold,
the multi-char fold will never be matched; just the first character of
the fold.

Spotted by Nicholas Clark.

Flags​:
  category=core
  severity=low

Site configuration information for perl 5.14.0​:

Configured by khw at Tue May 3 08​:46​:17 MDT 2011.

Summary of my perl5 (revision 5 version 14 subversion 0) configuration​:
  Commit id​: 2cf7ccf
  Platform​:
  osname=linux, osvers=2.6.35-28-generic-pae,
archname=i686-linux-thread-multi-64int-ld
  uname='linux karl 2.6.35-28-generic-pae #50-ubuntu smp fri mar 18
20​:43​:15 utc 2011 i686 gnulinux '
  config_args='-des -Dprefix=/home/khw/blead -Dusedevel
-D'optimize=-ggdb3' -A'optimize=-ggdb3' -A'optimize=-O0' -Dman1dir=none
-Dman3dir=none -DDEBUGGING -Dusemorebits -Dusethreads'
  hint=recommended, useposix=true, d_sigaction=define
  useithreads=define, usemultiplicity=define
  useperlio=define, d_sfio=undef, uselargefiles=define, usesocks=undef
  use64bitint=define, use64bitall=undef, uselongdouble=define
  usemymalloc=n, bincompat5005=undef
  Compiler​:
  cc='cc', ccflags ='-D_REENTRANT -D_GNU_SOURCE -DDEBUGGING
-fno-strict-aliasing -pipe -fstack-protector -I/usr/local/include
-D_LARGEFILE_SOURCE -D_FILE_OFFSET_BITS=64',
  optimize='-O0 -ggdb3',
  cppflags='-D_REENTRANT -D_GNU_SOURCE -DDEBUGGING
-fno-strict-aliasing -pipe -fstack-protector -I/usr/local/include'
  ccversion='', gccversion='4.4.5', gccosandvers=''
  intsize=4, longsize=4, ptrsize=4, doublesize=8, byteorder=12345678
  d_longlong=define, longlongsize=8, d_longdbl=define, longdblsize=12
  ivtype='long long', ivsize=8, nvtype='long double', nvsize=12,
Off_t='off_t', lseeksize=8
  alignbytes=4, prototype=define
  Linker and Libraries​:
  ld='cc', ldflags =' -fstack-protector -L/usr/local/lib'
  libpth=/usr/local/lib /lib/../lib /usr/lib/../lib /lib /usr/lib
/usr/lib/i686-linux-gnu
  libs=-lnsl -ldl -lm -lcrypt -lutil -lpthread -lc
  perllibs=-lnsl -ldl -lm -lcrypt -lutil -lpthread -lc
  libc=/lib/libc-2.12.1.so, so=so, useshrplib=false, libperl=libperl.a
  gnulibc_version='2.12.1'
  Dynamic Linking​:
  dlsrc=dl_dlopen.xs, dlext=so, d_dlsymun=undef, ccdlflags='-Wl,-E'
  cccdlflags='-fPIC', lddlflags='-shared -ggdb3 -ggdb3 -O0
-L/usr/local/lib -fstack-protector'

Locally applied patches​:
  RC1

@​INC for perl 5.14.0​:

/home/khw/blead/lib/perl5/site_perl/5.14.0/i686-linux-thread-multi-64int-ld
  /home/khw/blead/lib/perl5/site_perl/5.14.0
  /home/khw/blead/lib/perl5/5.14.0/i686-linux-thread-multi-64int-ld
  /home/khw/blead/lib/perl5/5.14.0
  /home/khw/blead/lib/perl5/site_perl
  .

Environment for perl 5.14.0​:
  HOME=/home/khw
  LANG=en_US.UTF-8
  LANGUAGE=en_US​:en
  LD_LIBRARY_PATH (unset)
  LOGDIR (unset)

PATH=/home/khw/bin​:/home/khw/print/bin​:/bin​:/usr/local/sbin​:/usr/local/bin​:/usr/sbin​:/usr/bin​:/sbin​:/usr/games​:/home/khw/cxoffice/bin
  PERL5OPT=-w
  PERL_BADLANG (unset)
  SHELL=/bin/ksh

From @khwilliamson

Fixed by commit
9d53c45

--
Karl Williamson

The RT System itself - Status changed from 'new' to 'open'

@khwilliamson - Status changed from 'open' to 'resolved'

From @cpansprout

On Sun Oct 14 08​:12​:41 2012, khw wrote​:

Fixed by commit
9d53c45

Does this affect look-behind?

--

Father Chrysostomos

From @khwilliamson

On 10/14/2012 11​:53 AM, Father Chrysostomos via RT wrote​:

On Sun Oct 14 08​:12​:41 2012, khw wrote​:

Fixed by commit
9d53c45

Does this affect look-behind?

I don't understand your question. Look-behind of classes that contain
multi-char folds did and do not work because we currently only do
fixed-length look-behind, and these by definition are not fixed-length.
  However, the fix includes what no one disagreed with before, which is
only if the character with a multi-character fold is mentioned
explicitly individually in the character class will its multi-char fold
be considered. So, look behind of /[\0-\xff]/i should now start
working, because the single character in its range that has a multi-char
fold is not mentioned explicitly. /[\0-\xff\xdf]/i will still match 1
or 2 characters, and so cannot be used in look-behind.

From @cpansprout

On Sun Oct 14 12​:08​:01 2012, public@​khwilliamson.com wrote​:

On 10/14/2012 11​:53 AM, Father Chrysostomos via RT wrote​:

On Sun Oct 14 08​:12​:41 2012, khw wrote​:

Fixed by commit
9d53c45

Does this affect look-behind?

I don't understand your question. Look-behind of classes that contain
multi-char folds did and do not work because we currently only do
fixed-length look-behind, and these by definition are not fixed-length.
However, the fix includes what no one disagreed with before, which is
only if the character with a multi-character fold is mentioned
explicitly individually in the character class will its multi-char fold
be considered. So, look behind of /[\0-\xff]/i should now start
working, because the single character in its range that has a multi-char
fold is not mentioned explicitly. /[\0-\xff\xdf]/i will still match 1
or 2 characters, and so cannot be used in look-behind.

Thank you. I couldn’t remember the details.

--

Father Chrysostomos