Add a note in perldelta about undefining *ISA

p4raw-id: //depot/perl@31550

diff --git a/pod/perl595delta.pod b/pod/perl595delta.pod
index 12b61d7..8ff50be 100644 (file)
--- a/pod/perl595delta.pod
+++ b/pod/perl595delta.pod
@@ -243,6 +243,11 @@ default MRO hasn't changed (DFS, for Depth First Search). Another MRO is
 available: the C3 algorithm. See L<mro> for more information.
 (Brandon Black)
 
+Note that, due to changes in the implentation of class hierarchy search,
+code that used to undef the C<*ISA> glob will most probably break. Anyway,
+undef'ing C<*ISA> had the side-effect of removing the magic on the @ISA
+array and should not have been done in the first place.
+
 =head2 bignum, bigint, bigrat
 
 The three numeric pragmas C<bignum>, C<bigint> and C<bigrat> are now