Merge lp:~lifeless/launchpad/bug-631884 into lp:launchpad

[Robert Collins]

Workaround bug 631884.

This works around bug 631884 permitting code that depends on features to be introduced without breaking throughout the test suite: we still need to address the root cause of bug 631884 and probably want participations in general to drive flags, but that is made difficult due to bug 623199.

[Michael Hudson-Doyle (mwhudson)]

As I said on IRC, I don't really think the comment is very helpful, but I can see the need for the code change.

review: Approve

=== modified file 'lib/lp/services/features/__init__.py'
--- lib/lp/services/features/__init__.py	2010-08-05 23:40:32 +0000
+++ lib/lp/services/features/__init__.py	2010-09-12 05:23:50 +0000
@@ -26,4 +26,9 @@
 
 def getFeatureFlag(flag):
     """Get the value of a flag for this thread's scopes."""
-    return per_thread.features.getFlag(flag)
+    # Workaround for bug 631884 - features have two homes, threads and
+    # requests.
+    features = getattr(per_thread, 'features', None)
+    if features is None:
+        return None
+    return features.getFlag(flag)

=== modified file 'lib/lp/services/features/tests/test_flags.py'
--- lib/lp/services/features/tests/test_flags.py	2010-08-20 20:31:18 +0000
+++ lib/lp/services/features/tests/test_flags.py	2010-09-12 05:23:50 +0000
@@ -129,6 +129,12 @@
         finally:
             per_thread.features = None
 
+    def test_threadGetFlagNoContext(self):
+        # If there is no context, please don't crash. workaround for the root
+        # cause in bug 631884.
+        per_thread.features = None
+        self.assertEqual(None, getFeatureFlag('ui.icing'))
+
     def testLazyScopeLookup(self):
         # feature scopes may be a bit expensive to look up, so we do it only
         # when it will make a difference to the result.