From: Jesse Luehrs <doy@tozt.net>
Date: Mon, 10 May 2010 21:47:16 +0000 (-0500)
Subject: move some metaclass compat docs from moose to here
X-Git-Tag: 1.02~5
X-Git-Url: http://git.shadowcat.co.uk/gitweb/gitweb.cgi?a=commitdiff_plain;h=3ab5cf4a1b6bc25e748ff14debc7fae766cd1a8c;p=gitmo%2FClass-MOP.git

move some metaclass compat docs from moose to here
---

diff --git a/lib/Class/MOP.pm b/lib/Class/MOP.pm
index 37a6af3..fbadae1 100644
--- a/lib/Class/MOP.pm
+++ b/lib/Class/MOP.pm
@@ -848,6 +848,18 @@ metaclass compatibility both upwards and downwards.
     |    A    |<----|    B    |
     +---------+     +---------+
 
+In actuality, I<all> of a class's metaclasses must be compatible,
+not just the class metaclass. That includes the instance, attribute,
+and method metaclasses, as well as the constructor and destructor
+classes.
+
+C<Class::MOP> will attempt to fix some simple types of
+incompatibilities. If all the metaclasses for the parent class are
+I<subclasses> of the child's metaclasses then we can simply replace
+the child's metaclasses with the parent's. In addition, if the child
+is missing a metaclass that the parent has, we can also just make the
+child use the parent's metaclass.
+
 As I said this is a highly esoteric topic and one you will only run
 into if you do a lot of subclassing of L<Class::MOP::Class>. If you
 are interested in why this is an issue see the paper I<Uniform and