overload.pm: Allow :: in method names

According to overload’s documentation, ‘[v]alues specified as strings
are interpreted as method names.’

But it behaves differently if the string contains a double colon:

use overload q\""\=>"bar::baz";
@bar::ISA = foo;
sub foo::baz{a}
warn bless[]
__END__
Undefined subroutine &bar::baz called at - line 4.

But apostrophes work as documented:

use overload q\""\=>"bar'baz";
@bar::ISA = foo;
sub foo::baz{a}
warn bless[]
__END__
a at - line 4.

I can’t see how the treatment of ::, introduced in a60067777, is not a
bug, though the method logic looks intentional:

+      if (not ref $sub and $sub !~ /::/) {

I suspect it was one of those things that was just not thought
through.  The pre-a60067777 logic was in gv.c, and treated strings
containing package separators just like any other strings:

          switch (SvTYPE(sv)) {
            default:
              if (!SvROK(sv)) {
                if (!SvOK(sv)) break;
		gv = gv_fetchmethod(stash, SvPV(sv, na));
                if (gv) cv = GvCV(gv);
                break;
              }
              cv = (CV*)SvRV(sv);

1 files changed, 15 insertions, 1 deletions

diff --git a/lib/overload.t b/lib/overload.t
index fed261dafb..7657010a2a 100644
--- a/lib/overload.t
+++ b/lib/overload.t
@@ -48,7 +48,7 @@ package main;
 
 $| = 1;
 BEGIN { require './test.pl' }
-plan tests => 5051;
+plan tests => 5053;
 
 use Scalar::Util qw(tainted);
 
@@ -2297,6 +2297,20 @@ is eval {"$a"}, overload::StrVal($a),
  'fallback is inherited by classes that have their own overloading'
  or diag $@;
 
+# package separators in method names
+{
+ package mane;
+ use overload q\""\ => "bear::strength";
+ use overload bool  => "bear'bouillon";
+}
+@bear::ISA = 'food';
+sub food::strength { 'twine' }
+sub food::bouillon { 0 }
+$a = bless[], mane::;
+is eval { "$a" }, 'twine', ':: in method name' or diag $@;
+is eval { !$a  },   1,      "' in method name" or diag $@;
+
+
 { # undefining the overload stash -- KEEP THIS TEST LAST
     package ant;
     use overload '+' => 'onion';