rt #72866 - add magic to arrayrefs assigned to *Foo::ISA

The fix for rt #60220 (26d68d86) updated the isa cache when an
arrayref was assigned to some *ISA, but didn't add the magic to the
new @ISA to catch any further updates to it.  Add the magic, and
tests.

1 files changed, 23 insertions, 1 deletions

diff --git a/t/mro/basic.t b/t/mro/basic.t
index a4d3015035..fbd3a6dd76 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 => 44);
+require q(./test.pl); plan(tests => 48);
 
 require mro;
 
@@ -250,6 +250,28 @@ is(eval { MRO_N->testfunc() }, 123);
 }
 
 {
+  # assigning @ISA via arrayref then modifying it RT 72866
+  {
+    package Q1;
+    sub foo {  }
+
+    package Q2;
+    sub bar { }
+
+    package Q3;
+  }
+  push @Q3::ISA, "Q1";
+  can_ok("Q3", "foo");
+  *Q3::ISA = [];
+  push @Q3::ISA, "Q1";
+  can_ok("Q3", "foo");
+  *Q3::ISA = [];
+  push @Q3::ISA, "Q2";
+  can_ok("Q3", "bar");
+  ok(!Q3->can("foo"), "can't call foo method any longer");
+}
+
+{
     # test mro::method_changed_in
     my $count = mro::get_pkg_gen("MRO_A");
     mro::method_changed_in("MRO_A");