job.save() shouldn't crash on unpickleable return value.

rq/job.py

@@ -441,7 +441,6 @@ class Job(object):
 
         You can exclude serializing the `meta` dictionary by setting
         `include_meta=False`.
-
         """
         obj = {}
         obj['created_at'] = utcformat(self.created_at or utcnow())
@@ -458,7 +457,10 @@ class Job(object):
         if self.ended_at is not None:
             obj['ended_at'] = utcformat(self.ended_at)
         if self._result is not None:
+            try:
                 obj['result'] = dumps(self._result)
+            except:
+                obj['result'] = 'Unpickleable return value'
         if self.exc_info is not None:
             obj['exc_info'] = self.exc_info
         if self.timeout is not None:

tests/test_job.py

@@ -5,6 +5,7 @@ from __future__ import (absolute_import, division, print_function,
 from datetime import datetime
 import time
 
+from Queue import Queue
 from tests import fixtures, RQTestCase
 from tests.helpers import strip_microseconds
 
@@ -292,6 +293,13 @@ class TestJob(RQTestCase):
         serialized2.pop('meta')
         self.assertDictEqual(serialized, serialized2)
 
+    def test_unpickleable_result(self):
+        """Unpickleable job result doesn't crash job.to_dict()"""
+        job = Job.create(func=fixtures.say_hello, args=('Lionel',))
+        job._result = Queue()
+        data = job.to_dict()
+        self.assertEqual(data['result'], 'Unpickleable return value')
+
     def test_result_ttl_is_persisted(self):
         """Ensure that job's result_ttl is set properly"""
         job = Job.create(func=fixtures.say_hello, args=('Lionel',), result_ttl=10)