mro::method_changed_in(..) ignores AUTOLOAD (RT #60220)

Patch modified to use a boolean rather than an integer for tracking
mro changes in S_glob_assign_ref and test fixed not to warn.

URL: http://rt.perl.org/rt3/Ticket/Display.html?id=60220

From the bug report:

-----------------------------------------------------------------
When creating a subclass dynamically, and when adding
AUTOLOAD dynamically into the parent class, then that
AUTOLOAD is not seen in the method cache, even after
a call to "mro::method_changed_in('Parent')".

It only appears in the method cache after a call
to mro::invalidate_all_method_caches().

The attached test file demonstrates the problem.

This was detected while trying to solve bug 40159 in DBIx::DataModel.
-----------------------------------------------------------------

Message-ID: <20081031132021.GA21341@mars.tony.develop-help.com>

1 files changed, 16 insertions, 1 deletions

diff --git a/t/mro/basic.t b/t/mro/basic.t
index e06622649e..8568517244 100644
--- a/t/mro/basic.t
+++ b/t/mro/basic.t
@@ -3,7 +3,7 @@
 use strict;
 use warnings;
 
-require q(./test.pl); plan(tests => 40);
+require q(./test.pl); plan(tests => 42);
 
 require mro;
 
@@ -233,3 +233,18 @@ is(eval { MRO_N->testfunc() }, 123);
     is($stk_obj->foo(3), 6);
 }
 
+{ 
+  {
+    # assigning @ISA via arrayref to globref RT 60220
+    package P1;
+    sub new { bless {}, shift }
+    
+    package P2;
+  }
+  *{P2::ISA} = [ 'P1' ];
+  my $foo = P2->new;
+  ok(!eval { $foo->bark }, "no bark method");
+  no warnings 'once';  # otherwise it'll bark about P1::bark used only once
+  *{P1::bark} = sub { "[bark]" };
+  is(scalar eval { $foo->bark }, "[bark]", "can bark now");
+}