Fixed issue with afterInit being called twice & errors in afterInit n…

…ot being caught when constructing a new model instance; refs bmuller#30; fixes bmuller#34

twistar/dbobject.py

@@ -58,6 +58,16 @@ class DBObject(Validator):
     # it will be of the form {'othername': <BelongsTo instance>, 'anothername': <HasMany instance>}
     RELATIONSHIP_CACHE = None
 
+    def __new__(cls, *args, **kwargs):
+        try:
+            ret = super(DBObject, cls).__new__(cls, *args, **kwargs)
+            ret.__init__(*args, **kwargs)
+        except:
+            return defer.fail()
+        else:
+            return defer.maybeDeferred(ret.afterInit).addCallback(lambda _: ret)
+
+
     def __init__(self, **kwargs):
         """
         Constructor.  DO NOT OVERWRITE.  Use the L{DBObject.afterInit} method.
@@ -377,7 +387,7 @@ def findOrCreate(klass, **attrs):
         def _findOrCreate(trans):
             def handle(result):
                 if len(result) == 0:
-                    return klass(**attrs).save()
+                    return klass(**attrs).addCallback(lambda inst: inst.save())
                 return result[0]
             return klass.findBy(**attrs).addCallback(handle)
         return _findOrCreate()

twistar/utils.py

@@ -44,15 +44,13 @@ def createInstances(props, klass):
     @return: A C{Deferred} that will pass the result to a callback
     """
     if type(props) is list:
-        ks = [klass(**prop) for prop in props]
-        ds = [defer.maybeDeferred(k.afterInit) for k in ks]
-        return defer.DeferredList(ds).addCallback(lambda _: ks)
-
-    if props is not None:
-        k = klass(**props)
-        return defer.maybeDeferred(k.afterInit).addCallback(lambda _: k)
-
-    return defer.succeed(None)
+        return defer.DeferredList(
+            [klass(**prop) for prop in props], fireOnOneErrback=True, consumeErrors=True
+        ).addCallback(lambda result: [x[1] for x in result])
+    elif props is not None:
+        return klass(**props)
+    else:
+        return defer.succeed(None)
 
 
 def dictToWhere(attrs, joiner="AND"):