Re: \z vs \Z vs $

>>>>>> "TC" == Tom Christiansen <[email protected]> writes:

>>> Could you explain what the problem is?

>TC> /$/ does not only match at the end of the string.
>TC> It also matches one character fewer.  This makes
>TC> code like $path =~ /etc$/ "wrong".

>Sorry, I'm missing it.

I know.  

On your "longest match", you are committing the classic error of thinking
green more important than eagerness.  It's not.

This is unrelated to /m.

Go back and read all the insanities we (mostly gbacon and your
truly) went through to fix the 5.6 release's modules.  People coded
them *WRONG*.  Wrong means incorrect behaviour.  Sometimes this
even leads to security foo.

BOTTOM LINE: You cannot use /foo$/ to say "does the string end in `foo'?".
You can't do that.  You can't even use /s to fix it.  It doesn't fix it.

This is an annoying gotcha.  Larry once said that he wished he had made  \Z
do what \z now does.  One would like $ to (be able to) mean "ONLY AT END OF
STRING".

--tom

EXAMPLE 1:

--- /usr/local/lib/perl5/5.00554/File/Basename.pm	Mon Jan  4 13:00:53 1999
+++ /usr/local/lib/perl5/5.6.0/File/Basename.pm	Sun Mar 12 22:24:29 2000
@@ -37,10 +37,10 @@
 "VMS", "MSDOS", "MacOS", "AmigaOS" or "MSWin32", the file specification 
 syntax of that operating system is used in future calls to 
 fileparse(), basename(), and dirname().  If it contains none of
-these substrings, UNIX syntax is used.  This pattern matching is
+these substrings, Unix syntax is used.  This pattern matching is
 case-insensitive.  If you've selected VMS syntax, and the file
 specification you pass to one of these routines contains a "/",
-they assume you are using UNIX emulation and apply the UNIX syntax
+they assume you are using Unix emulation and apply the Unix syntax
 rules instead, for that function call only.
 
 If the argument passed to it contains one of the substrings "VMS",
@@ -73,7 +73,7 @@
 
 =head1 EXAMPLES
 
-Using UNIX file syntax:
+Using Unix file syntax:
 
     ($base,$path,$type) = fileparse('/virgil/aeneid/draft.book7',
 				    '\.book\d+');
@@ -102,7 +102,7 @@
 The basename() routine returns the first element of the list produced
 by calling fileparse() with the same arguments, except that it always
 quotes metacharacters in the given suffixes.  It is provided for
-programmer compatibility with the UNIX shell command basename(1).
+programmer compatibility with the Unix shell command basename(1).
 
 =item C<dirname>
 
@@ -111,8 +111,8 @@
 second element of the list produced by calling fileparse() with the same
 input file specification.  (Under VMS, if there is no directory information
 in the input file specification, then the current default device and
-directory are returned.)  When using UNIX or MSDOS syntax, the return
-value conforms to the behavior of the UNIX shell command dirname(1).  This
+directory are returned.)  When using Unix or MSDOS syntax, the return
+value conforms to the behavior of the Unix shell command dirname(1).  This
 is usually the same as the behavior of fileparse(), but differs in some
 cases.  For example, for the input file specification F<lib/>, fileparse()
 considers the directory name to be F<lib/>, while dirname() considers the
@@ -124,12 +124,22 @@
 
 
 ## use strict;
-use re 'taint';
+# A bit of juggling to insure that C<use re 'taint';> always works, since
+# File::Basename is used during the Perl build, when the re extension may
+# not be available.
+BEGIN {
+  unless (eval { require re; })
+    { eval ' sub re::import { $^H |= 0x00100000; } ' }
+  import re 'taint';
+}
+
+
 
+use 5.005_64;
+our(@ISA, @EXPORT, $VERSION, $Fileparse_fstype, $Fileparse_igncase);
 require Exporter;
 @ISA = qw(Exporter);
 @EXPORT = qw(fileparse fileparse_set_fstype basename dirname);
-use vars qw($VERSION $Fileparse_fstype $Fileparse_igncase);
 $VERSION = "2.6";
 
 
@@ -162,23 +172,23 @@
   if ($fstype =~ /^VMS/i) {
     if ($fullname =~ m#/#) { $fstype = '' }  # We're doing Unix emulation
     else {
-      ($dirpath,$basename) = ($fullname =~ /^(.*[:>\]])?(.*)/);
+      ($dirpath,$basename) = ($fullname =~ /^(.*[:>\]])?(.*)/s);
       $dirpath ||= '';  # should always be defined
     }
   }
   if ($fstype =~ /^MS(DOS|Win32)/i) {
-    ($dirpath,$basename) = ($fullname =~ /^((?:.*[:\\\/])?)(.*)/);
-    $dirpath .= '.\\' unless $dirpath =~ /[\\\/]$/;
+    ($dirpath,$basename) = ($fullname =~ /^((?:.*[:\\\/])?)(.*)/s);
+    $dirpath .= '.\\' unless $dirpath =~ /[\\\/]\z/;
   }
-  elsif ($fstype =~ /^MacOS/i) {
-    ($dirpath,$basename) = ($fullname =~ /^(.*:)?(.*)/);
+  elsif ($fstype =~ /^MacOS/si) {
+    ($dirpath,$basename) = ($fullname =~ /^(.*:)?(.*)/s);
   }
   elsif ($fstype =~ /^AmigaOS/i) {
-    ($dirpath,$basename) = ($fullname =~ /(.*[:\/])?(.*)/);
+    ($dirpath,$basename) = ($fullname =~ /(.*[:\/])?(.*)/s);
     $dirpath = './' unless $dirpath;
   }
   elsif ($fstype !~ /^VMS/i) {  # default to Unix
-    ($dirpath,$basename) = ($fullname =~ m#^(.*/)?(.*)#);
+    ($dirpath,$basename) = ($fullname =~ m#^(.*/)?(.*)#s);
     if ($^O eq 'VMS' and $fullname =~ m:/[^/]+/000000/?:) {
       # dev:[000000] is top of VMS tree, similar to Unix '/'
       ($basename,$dirpath) = ('',$fullname);
@@ -190,7 +200,7 @@
     $tail = '';
     foreach $suffix (@suffices) {
       my $pat = ($igncase ? '(?i)' : '') . "($suffix)\$";
-      if ($basename =~ s/$pat//) {
+      if ($basename =~ s/$pat//s) {
         $taint .= substr($suffix,0,0);
         $tail = $1 . $tail;
       }
@@ -228,30 +238,30 @@
     }
     if ($fstype =~ /MacOS/i) { return $dirname }
     elsif ($fstype =~ /MSDOS/i) { 
-        $dirname =~ s/([^:])[\\\/]*$/$1/;
+        $dirname =~ s/([^:])[\\\/]*\z/$1/;
         unless( length($basename) ) {
 	    ($basename,$dirname) = fileparse $dirname;
-	    $dirname =~ s/([^:])[\\\/]*$/$1/;
+	    $dirname =~ s/([^:])[\\\/]*\z/$1/;
 	}
     }
     elsif ($fstype =~ /MSWin32/i) { 
-        $dirname =~ s/([^:])[\\\/]*$/$1/;
+        $dirname =~ s/([^:])[\\\/]*\z/$1/;
         unless( length($basename) ) {
 	    ($basename,$dirname) = fileparse $dirname;
-	    $dirname =~ s/([^:])[\\\/]*$/$1/;
+	    $dirname =~ s/([^:])[\\\/]*\z/$1/;
 	}
     }
     elsif ($fstype =~ /AmigaOS/i) {
-        if ( $dirname =~ /:$/) { return $dirname }
+        if ( $dirname =~ /:\z/) { return $dirname }
         chop $dirname;
-        $dirname =~ s#[^:/]+$## unless length($basename);
+        $dirname =~ s#[^:/]+\z## unless length($basename);
     }
     else { 
-        $dirname =~ s:(.)/*$:$1:;
+        $dirname =~ s:(.)/*\z:$1:s;
         unless( length($basename) ) {
 	    local($File::Basename::Fileparse_fstype) = $fstype;
 	    ($basename,$dirname) = fileparse $dirname;
-	    $dirname =~ s:(.)/*$:$1:;
+	    $dirname =~ s:(.)/*\z:$1:s;
 	}
     }
 
EXAMPLE 2:

(selected File::Find diffs)
-        /^\.nfs.*$/ &&
+        /^\.nfs.*\z/s &&
-               $fixtopdir =~ s/\.dir$// if $Is_VMS;
+        $top_item =~ s|/\z|| unless $top_item eq '/';
+               $top_item =~ s/\.dir\z// if $Is_VMS;
+    my $dir_pref= ( $p_dir eq '/' ? '/' : "$p_dir/" );
+               next if $FN =~ /^\.{1,2}\z/;
-                       $name =~ s/\.dir$// if $Is_VMS;
+               next if $FN =~ /^\.{1,2}\z/;
+                       $FN =~ s/\.dir\z// if $Is_VMS;
+           $dir_name = ($p_dir eq '/' ? "/$dir_rel" : "$p_dir/$dir_rel");
+    my $dir_pref = ( $p_dir   eq '/' ? '/' : "$p_dir/" );
+    my $loc_pref = ( $dir_loc eq '/' ? '/' : "$dir_loc/" );
+           next if $FN =~ /^\.{1,2}\z/;
+           $dir_name = ($p_dir eq '/' ? "/$dir_rel" : "$p_dir/$dir_rel");