From c12cc036ebb693083392ceb64895233e5045a05e Mon Sep 17 00:00:00 2001
From: Ruby Loo <rloo@yahoo-inc.com>
Date: Wed, 13 Jan 2016 20:59:06 +0000
Subject: [PATCH] Document backwards compat for passthru methods

This adds a section to the vendor-passthru documentation
about backwards compatibility (which isn't necessary but
desirable) for vendor-passthru methods.

Change-Id: I27b4a6638772e3508e9dab34d90ca904198352f0
---
 doc/source/dev/vendor-passthru.rst | 13 +++++++++++++
 1 file changed, 13 insertions(+)

diff --git a/doc/source/dev/vendor-passthru.rst b/doc/source/dev/vendor-passthru.rst
index 03d7afe0d3..0a2b16440d 100644
--- a/doc/source/dev/vendor-passthru.rst
+++ b/doc/source/dev/vendor-passthru.rst
@@ -129,3 +129,16 @@ Both decorators accepts the same parameters:
    Each asynchronous request consumes a worker thread in the
    ``ironic-conductor`` process. This can lead to starvation of the
    thread pool, resulting in a denial of service.
+
+Backwards Compatibility
+=======================
+
+There is no requirement that changes to a vendor method be backwards
+compatible. However, for your users' sakes, we highly recommend that
+you do so.
+
+If you are changing the exceptions being raised, you might want to ensure
+that the same HTTP code is being returned to the user.
+
+For non-backwards compatibility, please make sure you add a release
+note that indicates this.