Replace distributor deferred list, with a simple for loop until I understand why the former breaks and the latter doesn't

synapse/util/distributor.py

@@ -115,10 +115,10 @@ class Signal(object):
                             failure.value,
                             failure.getTracebackObject()))
                     if not self.suppress_failures:
-                        raise failure
+                        failure.raiseException()
                 deferreds.append(d.addErrback(eb))
-
+            results = []
-            result = yield defer.DeferredList(
+            for deferred in deferreds:
-                deferreds, fireOnOneErrback=not self.suppress_failures
+                result = yield deferred
-            )
+                results.append(results)
-        defer.returnValue(result)
+        defer.returnValue(results)

tests/test_distributor.py

@@ -13,12 +13,13 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
-from tests import unittest
+from . import unittest
 from twisted.internet import defer
 
 from mock import Mock, patch
 
 from synapse.util.distributor import Distributor
+from synapse.util.async import run_on_reactor
 
 
 class DistributorTestCase(unittest.TestCase):
@@ -26,6 +27,7 @@ class DistributorTestCase(unittest.TestCase):
     def setUp(self):
         self.dist = Distributor()
 
+    @defer.inlineCallbacks
     def test_signal_dispatch(self):
         self.dist.declare("alert")
 
@@ -33,10 +35,11 @@ class DistributorTestCase(unittest.TestCase):
         self.dist.observe("alert", observer)
 
         d = self.dist.fire("alert", 1, 2, 3)
-
+        yield d
         self.assertTrue(d.called)
         observer.assert_called_with(1, 2, 3)
 
+    @defer.inlineCallbacks
     def test_signal_dispatch_deferred(self):
         self.dist.declare("whine")
 
@@ -50,8 +53,10 @@ class DistributorTestCase(unittest.TestCase):
         self.assertFalse(d_outer.called)
 
         d_inner.callback(None)
+        yield d_outer
         self.assertTrue(d_outer.called)
 
+    @defer.inlineCallbacks
     def test_signal_catch(self):
         self.dist.declare("alarm")
 
@@ -65,6 +70,7 @@ class DistributorTestCase(unittest.TestCase):
                 spec=["warning"]
         ) as mock_logger:
             d = self.dist.fire("alarm", "Go")
+            yield d
             self.assertTrue(d.called)
 
             observers[0].assert_called_once("Go")
@@ -81,23 +87,28 @@ class DistributorTestCase(unittest.TestCase):
 
         self.dist.declare("whail")
 
-        observer = Mock()
+        class MyException(Exception):
-        observer.return_value = defer.fail(
+            pass
-            Exception("Oopsie")
+
-        )
+        @defer.inlineCallbacks
+        def observer():
+            yield run_on_reactor()
+            raise MyException("Oopsie")
 
         self.dist.observe("whail", observer)
 
         d = self.dist.fire("whail")
 
-        yield self.assertFailure(d, Exception)
+        yield self.assertFailure(d, MyException)
+        self.dist.suppress_failures = True
 
+    @defer.inlineCallbacks
     def test_signal_prereg(self):
         observer = Mock()
         self.dist.observe("flare", observer)
 
         self.dist.declare("flare")
-        self.dist.fire("flare", 4, 5)
+        yield self.dist.fire("flare", 4, 5)
 
         observer.assert_called_with(4, 5)