5.005_63: Regex strangeness

[p5pRT]

Migrated from rt.perl.org#1894 (status was 'resolved')

Searchable as RT1894$

[p5pRT]

From @sciurius

The second match should succeed as well.

$x = "\nx\taa\n";
print "This one matches\n" if $x =~ /^\S\saa$/m;
print "But this one doesn't\n" if $x =~ /^\S\s+aa$/m;

Perl Info

Site configuration information for perl 5.00563:

Configured by jv at Mon Dec 13 17:32:43 MET 1999.

Summary of my perl5 (revision 5.0 version 5 subversion 63) configuration:
  Platform:
    osname=linux, osvers=2.2.13, archname=i386-linux
    uname='linux phoenix.squirrel.nl 2.2.13 #1 fri oct 22 12:28:44 mest 1999 i686 unknown '
    config_args='-des -Dprefix=/usr -Dinstallprefix=/usr -Darchname=i386-linux -Dd_dosuid'
    hint=recommended, useposix=true, d_sigaction=define
    usethreads=undef useperlio=undef d_sfio=undef
    use64bits=undef usemultiplicity=undef
  Compiler:
    cc='cc', optimize='-O2', gccversion=2.8.1
    cppflags='-Dbool=char -DHAS_BOOL -I/usr/local/include'
    ccflags ='-Dbool=char -DHAS_BOOL -I/usr/local/include'
    stdchar='char', d_stdstdio=define, usevfork=false
    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 =' -L/usr/local/lib'
    libpth=/usr/local/lib /lib /usr/lib
    libs=-lnsl -lndbm -lgdbm -ldb -ldl -lm -lc -lposix -lcrypt
    libc=/lib/libc-2.0.7.so, so=so, useshrplib=false, libperl=libperl.a
  Dynamic Linking:
    dlsrc=dl_dlopen.xs, dlext=so, d_dlsymun=undef, ccdlflags='-rdynamic'
    cccdlflags='-fpic', lddlflags='-shared -L/usr/local/lib'

Locally applied patches:
    


@INC for perl 5.00563:
    /usr/lib/perl5/5.00563/i386-linux
    /usr/lib/perl5/5.00563
    /usr/lib/site_perl/5.00563/i386-linux
    /usr/lib/site_perl
    .


Environment for perl 5.00563:
    HOME=/home/jv
    LANG (unset)
    LANGUAGE (unset)
    LD_LIBRARY_PATH (unset)
    LOGDIR (unset)
    PATH=.:/home/jv/bin:/usr/local/bin:/bin:/usr/bin:/usr/X11/bin
    PERL_BADLANG (unset)
    SHELL=/bin/tcsh

[p5pRT]

From [Unknown Contact. See original ticket]

Johan Vromans writes​:

The second match should succeed as well.

$x = "\nx\taa\n";
print "This one matches\n" if $x =~ /^\S\saa$/m;
print "But this one doesn't\n" if $x =~ /^\S\s+aa$/m;

[I did not look into alleged UTEST failures yet...]

Enjoy,
Ilya

Inline Patch

--- ./regexec.c~	Wed Dec  8 15:17:53 1999
+++ ./regexec.c	Fri Dec 17 03:08:26 1999
@@ -730,13 +730,17 @@ Perl_re_intuit_start(pTHX_ regexp *prog,
 			  (long)(other_last - i_strpos)) );
 		goto do_other_anchored;
 	    }
-	    if (!prog->float_substr) {	/* Could have been deleted */
-		if (ml_anch) {
-		    s = t = t + 1;
-		    goto try_at_offset;
-		}
-		goto fail;
+	    /* Another way we could have checked stclass at the
+               current position only: */
+	    if (ml_anch) {
+		s = t = t + 1;
+		DEBUG_r( PerlIO_printf(Perl_debug_log,
+			  "Trying /^/m starting at offset %ld...\n",
+			  (long)(t - i_strpos)) );
+		goto try_at_offset;
 	    }
+	    if (!prog->float_substr)	/* Could have been deleted */
+		goto fail;
 	    /* Check is floating subtring. */
 	  retry_floating_check:
 	    t = check_at - start_shift;
--- ./t/op/re_tests~	Wed Dec  8 15:17:53 1999
+++ ./t/op/re_tests	Wed Dec 15 17:57:32 1999
@@ -748,3 +748,4 @@ tt+$	xxxtt	y	-	-
 '\.c(pp|xx|c)?$'i	IO.c	y	-	-
 '(\.c(pp|xx|c)?$)'i	IO.c	y	$1	.c
 ^([a-z]:)	C:/	n	-	-
+'^\S\s+aa$'m	\nx aa	y	-	-

[p5pRT]

From [Unknown Contact. See original ticket]

Johan Vromans writes​:

The second match should succeed as well.

$x = "\nx\taa\n";
print "This one matches\n" if $x =~ /^\S\saa$/m;
print "But this one doesn't\n" if $x =~ /^\S\s+aa$/m;

Oups, forgot to thank you a lot for your investigations.

Sorry,
Ilya