[perl #50538] when( @n && %n ) fails to smart match

# New Ticket Created by  "brian d foy" 
# Please include the string:  [perl #50538]
# in the subject line of all future correspondence about this issue. 
# <URL: http://rt.perl.org/rt3/Ticket/Display.html?id=50538 >


This is a bug report for perl from brian.d.foy@gmail.com,
generated with the help of perlbug 1.35 running under perl v5.10.0.


-----------------------------------------------------------------
[Please enter your report here]

I first mentioned this on p5p in " Clarifying smart match behaviour in
when( ... && ... )" at
http://groups.google.com/group/perl.perl5.porters/browse_thread/thread/5f5d24422227e57a/2c2aa46cdeabcbcc?lnk=st&q=smart+match+foy#2c2aa46cdeabcbcc

With && in a when() and when both arguments are arrays and hashes, the
smart match doesn't come out right. If it is coming out right, then
there needs to be a doc fix. No one has spoken up to say it should be
one way or the other.

Here's a patch to t/op/switch.t that tests the problem in three
different cases:

--- t/op/switch.t	2008-02-04 21:04:17.000000000 -0600
+++ t/op/switch-new.t	2008-02-04 21:13:27.000000000 -0600
@@ -8,7 +8,7 @@
 use strict;
 use warnings;

-use Test::More tests => 108;
+use Test::More tests => 111;

 # The behaviour of the feature pragma should be tested by lib/switch.t
 # using the tests in t/lib/switch/*. This file tests the behaviour of
@@ -520,6 +520,66 @@
     ok($ok, '((1 == $ok) || "foo") smartmatched');
 }

+{ # this should smart match on each side of &&
+	my @n = qw(fred barney betty);
+	my @m = @n;
+	
+	my $ok = 0;
+	given( "fred" ) {
+	when( @n ) {
+		$ok++; continue;
+	}
+	when( @m ) {
+		$ok++; continue;
+	}
+	when( @m && @n ) {
+		$ok++;
+	}
+	}
+
+	is($ok, 3, '(@n && @m) smart-matched');	
+}
+
+{ # this should smart match on each side of &&
+	my @n = qw(fred barney betty);
+	my %n = map { $_, 1 } @n;
+	
+	my $ok = 0;
+	given( "fred" ) {
+	when( @n ) {
+		$ok++; continue;
+	}
+	when( %n ) {
+		$ok++; continue;
+	}
+	when( @n && %n ) {
+		$ok++;
+	}
+	}
+
+	is($ok, 3, '(@n && %n) smart-matched');	
+}
+
+{ # this should smart match on each side of &&
+	my %n = map { $_, 1 } qw(fred barney betty);
+	my %m = %n;
+	
+	my $ok = 0;
+	given( "fred" ) {
+	when( %m ) {
+		$ok++; continue;
+	}
+	when( %n ) {
+		$ok++; continue;
+	}
+	when( %m && %n ) {
+		$ok++;
+	}
+	}
+
+	is($ok, 3, '(%m && %n) smart-matched');	
+}
+
 # Make sure we aren't invoking the get-magic more than once

 { # A helper class to count the number of accesses.
@@ -689,7 +749,7 @@
 	    	q{Can't "break" in a loop topicalizer});
 	}
 	when (1) {
-	    is($first, 1, "Lecical loop: first");
+	    is($first, 1, "Lexical loop: first");
 	    $first = 0;
 	    # Implicit break is okay
 	}



[Please do not change anything below this line]
-----------------------------------------------------------------
---
Flags:
    category=core
    severity=high
---
This perlbug was built using Perl v5.8.8 - Mon Apr  9 10:35:38 CDT 2007
It is being executed now by  Perl v5.10.0 - Sun Dec  2 12:12:45 CST 2007.

Site configuration information for perl v5.10.0:

Configured by brian at Sun Dec  2 12:12:45 CST 2007.

Summary of my perl5 (revision 5 version 10 subversion 0) configuration:
  Platform:
    osname=darwin, osvers=8.10.1, archname=darwin-2level
    uname='darwin alexandria2-10.nyc.access.net 8.10.1 darwin kernel
version 8.10.1: wed may 23 16:33:00 pdt 2007;
root:xnu-792.22.5~1release_i386 i386 i386 '
    config_args=''
    hint=recommended, useposix=true, d_sigaction=define
    useithreads=undef, usemultiplicity=undef
    useperlio=define, d_sfio=undef, uselargefiles=define, usesocks=undef
    use64bitint=undef, use64bitall=undef, uselongdouble=undef
    usemymalloc=n, bincompat5005=undef
  Compiler:
    cc='cc', ccflags ='-fno-common -DPERL_DARWIN -no-cpp-precomp
-fno-strict-aliasing -pipe -I/usr/local/include -I/opt/local/include',
    optimize='-O3',
    cppflags='-no-cpp-precomp -fno-common -DPERL_DARWIN
-no-cpp-precomp -fno-strict-aliasing -pipe -I/usr/local/include
-I/opt/local/include'
    ccversion='', gccversion='4.0.1 (Apple Computer, Inc. build
5363)', gccosandvers=''
    intsize=4, longsize=4, ptrsize=4, doublesize=8, byteorder=1234
    d_longlong=define, longlongsize=8, d_longdbl=define, longdblsize=16
    ivtype='long', ivsize=4, nvtype='double', nvsize=8, Off_t='off_t',
lseeksize=8
    alignbytes=8, prototype=define
  Linker and Libraries:
    ld='env MACOSX_DEPLOYMENT_TARGET=10.3 cc', ldflags ='
-L/usr/local/lib -L/opt/local/lib'
    libpth=/usr/local/lib /opt/local/lib /usr/lib
    libs=-ldbm -ldl -lm -lc
    perllibs=-ldl -lm -lc
    libc=/usr/lib/libc.dylib, so=dylib, useshrplib=false, libperl=libperl.a
    gnulibc_version=''
  Dynamic Linking:
    dlsrc=dl_dlopen.xs, dlext=bundle, d_dlsymun=undef, ccdlflags=' '
    cccdlflags=' ', lddlflags=' -bundle -undefined dynamic_lookup
-L/usr/local/lib -L/opt/local/lib'

Locally applied patches:


---
@INC for perl v5.10.0:
    /usr/local/perls/perl-5.10.0-rc2/lib/5.10.0/darwin-2level
    /usr/local/perls/perl-5.10.0-rc2/lib/5.10.0
    /usr/local/perls/perl-5.10.0-rc2/lib/site_perl/5.10.0/darwin-2level
    /usr/local/perls/perl-5.10.0-rc2/lib/site_perl/5.10.0
    .

---
Environment for perl v5.10.0:
    DYLD_LIBRARY_PATH (unset)
    HOME=/Users/brian
    LANG=en_US
    LANGUAGE (unset)
    LC_ALL=C
    LD_LIBRARY_PATH (unset)
    LOGDIR (unset)
    PATH=/Library/Frameworks/Python.framework/Versions/Current/bin:/Users/brian/bin:/usr/local/bin:/opt/local/bin:/Users/brian/TPR/scripts:/bin:/usr/bin:/sbin:/usr/sbin:/usr/local/mysql/bin:/usr/X11R6/bin:/usr/local/teTeX/bin/powerpc-apple-darwin-current:/usr/local/pgsql/bin:/usr/local/gcj/bin
    PERL_BADLANG (unset)
    SHELL=/bin/bash


-- 
brian d foy <brian.d.foy@gmail.com>
http://www.pair.com/~comdog/

• [perl #50538] when( @n && %n ) fails to smart match by brian d foy