From 02e1fe45e4bb2d7473296d2b8c2114680d9c75c2 Mon Sep 17 00:00:00 2001
From: Chris McDonough <chrism@agendaless.com>
Date: Wed, 23 Sep 2009 09:30:46 +0000
Subject: - Speed up ``repoze.bfg.location.lineage`` slightly.

---
 CHANGES.txt            |  9 +++++++++
 repoze/bfg/location.py | 12 +++++++++++-
 2 files changed, 20 insertions(+), 1 deletion(-)

diff --git a/CHANGES.txt b/CHANGES.txt
index bd28f160b..42a87940c 100644
--- a/CHANGES.txt
+++ b/CHANGES.txt
@@ -1,3 +1,12 @@
+Next release
+============
+
+Features
+--------
+
+- Speed up ``repoze.bfg.location.lineage`` slightly.
+
+
 1.1a4 (2009-09-23)
 ==================
 
diff --git a/repoze/bfg/location.py b/repoze/bfg/location.py
index adb01d129..8e8eff671 100644
--- a/repoze/bfg/location.py
+++ b/repoze/bfg/location.py
@@ -55,5 +55,15 @@ def lineage(model):
     """
     while model is not None:
         yield model
-        model = getattr(model, '__parent__', None)
+        # The common case is that the AttributeError exception below
+        # is exceptional as long as the developer is a "good citizen"
+        # who has a root object with a __parent__ of None.  Using an
+        # exception here instead of a getattr with a default is an
+        # important micro-optimization, because this function is
+        # called in any non-trivial application over and over again to
+        # generate URLs and paths.
+        try:
+            model = model.__parent__
+        except AttributeError:
+            model = None
 
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