Fix exception swallowing in CompositePluginManager.start.

envisage/composite_plugin_manager.py

@@ -129,7 +129,8 @@ def remove_plugin(self, plugin):
     def start(self):
         """ Start the plugin manager. """
 
-        map(lambda plugin: self.start_plugin(plugin), self)
+        for plugin in self:
+            self.start_plugin(plugin)
 
         return
 
@@ -154,7 +155,8 @@ def stop(self):
         stop_order = list(iter(self))
         stop_order.reverse()
 
-        map(lambda plugin: self.stop_plugin(plugin), stop_order)
+        for plugin in stop_order:
+            self.stop_plugin(plugin)
 
         return
 

envisage/tests/composite_plugin_manager_test_case.py

@@ -36,6 +36,19 @@ def stop(self):
         return
 
 
+class CustomException(Exception):
+    """ Custom exception used for testing purposes. """
+
+    pass
+
+
+class RaisingPluginManager(PluginManager):
+    """ A PluginManager that raises on iteration. """
+
+    def __iter__(self):
+        raise CustomException("Something went wrong.")
+
+
 class CompositePluginManagerTestCase(unittest.TestCase):
     """ Tests for the composite plugin manager. """
 
@@ -160,6 +173,13 @@ def removed(obj, trait_name, old, new):
 
         return
 
+    def test_correct_exception_propagated_from_plugin_manager(self):
+        plugin_manager = CompositePluginManager(
+            plugin_managers=[RaisingPluginManager()]
+        )
+
+        self.assertRaises(CustomException, plugin_manager.start)
+
     #### Private protocol #####################################################
 
     def _plugin_count(self, plugin_manager):