X-Git-Url: http://git.freeside.biz/gitweb/?a=blobdiff_plain;f=rt%2Flib%2FRT%2FStyleGuide.pod;fp=rt%2Flib%2FRT%2FStyleGuide.pod;h=d958c87d478c5478f79e7dfa0dbbe14d3bc31b07;hb=33beebf4cb42eba3e1dd868ad5e0af102de961da;hp=84ccb89df76d1dc836e74a6ae6a9451bce8f8a51;hpb=7ac86daf67b0a95153b736d5811f9050363f6553;p=freeside.git

diff --git a/rt/lib/RT/StyleGuide.pod b/rt/lib/RT/StyleGuide.pod
index 84ccb89df..d958c87d4 100644
--- a/rt/lib/RT/StyleGuide.pod
+++ b/rt/lib/RT/StyleGuide.pod
@@ -892,6 +892,22 @@ There are some legacy fields that did not follow this rule, namely
 C<ACL.PrincipalId>, C<GroupMembers.GroupId> and C<Attachments.TransactionId>,
 but new tables are expected to be consistent.
 
+
+=head1 EXTENDING RT CLASSES
+
+=head2 The Overlay mechanism
+
+RT's classes allow "overlay" methods to be placed into files named Filename_Vendor.pm and Filename_Local.pm
+_Vendor is for 3rd-party vendor add-ons, while _Local is for site-local customizations.
+
+These overlay files can contain new subs or subs to replace existing subs in this module.
+
+Each of these files should begin with the line
+
+   no warnings qw(redefine);
+
+so that perl does not kick and scream when you redefine a subroutine or variable in your overlay.
+
 =head1 TO DO
 
 Talk about DBIx::SearchBuilder