Result.get on a chain now propagates exceptions for all tasks in the chain. Also parent is now serialized when using JSON. Closes #1014

celery/result.py

@@ -28,10 +28,13 @@ def from_serializable(r):
     # earlier backends may just pickle, so check if
     # result is already prepared.
     if not isinstance(r, ResultBase):
-        id, nodes = r
+        id = parent = None
+        res, nodes = r
         if nodes:
-            return GroupResult(id, [AsyncResult(id) for id, _ in nodes])
-        return AsyncResult(id)
+            return GroupResult(res, [AsyncResult(id) for id, _ in nodes])
+        if isinstance(res, (list, tuple)):
+            id, parent = res[0], res[1]
+        return AsyncResult(id, parent=parent)
     return r
 
 
@@ -69,7 +72,7 @@ class AsyncResult(ResultBase):
         self.parent = parent
 
     def serializable(self):
-        return self.id, None
+        return [self.id, self.parent and self.parent.id], None
 
     def forget(self):
         """Forget about (and possibly remove the result of) this task."""
@@ -114,11 +117,21 @@ class AsyncResult(ResultBase):
         be re-raised.
 
         """
+        if propagate and self.parent:
+            for node in reversed(list(self._parents())):
+                node.get(propagate=True, timeout=timeout, interval=interval)
+
         return self.backend.wait_for(self.id, timeout=timeout,
                                               propagate=propagate,
                                               interval=interval)
     wait = get  # deprecated alias to :meth:`get`.
 
+    def _parents(self):
+        node = self.parent
+        while node:
+            yield node
+            node = node.parent
+
     def collect(self, intermediate=False, **kwargs):
         """Iterator, like :meth:`get` will wait for the task to complete,
         but will also follow :class:`AsyncResult` and :class:`ResultSet`