[TINKERPOP-2395] Gremlin Python doesn't support list as keys in groupCount

• Type: Improvement
• Status: Closed
• Priority: Major
• Resolution: Fixed
• Affects Version/s: 3.4.7
• Fix Version/s: 3.5.0
• Component/s: python
• Assignee: Stephen Mallette
• Reporter: Connor Skennerton
• Created: 27/Jul/20 19:46
• Updated: 08/Feb/21 17:19
• Resolved: 08/Feb/21 17:19

Description

The following works fine in the console but fails when converted to python using gremlin-server 3.4.7.

graph = TinkerGraph.open()
g = graph.traversal()
g.addV('test').property(set, 'name', 'name1').property(set, 'name', 'name2')
g.addV('test').property(set, 'name', 'name1').property(set, 'name', 'name2')
g.addV('source').property(set, 'name', 'source')
g.V(0L).as('0').V(3L).as('3').V(6L).as('6').addE('root').from('6').to('0').addE('root').from('6').to('3')
g.V().has('name', 'source').out('root').groupCount().by(values('name').fold())
==>[[name1,name2]:2]

The stack trace from python is as follows

 File "/Users/connor.skennerton/.pyenv/versions/dogma/lib/python3.6/site-packages/gremlin_python/driver/connection.py", line 83, in _receive
    status_code = self._protocol.data_received(data, self._results)
  File "/Users/connor.skennerton/.pyenv/versions/dogma/lib/python3.6/site-packages/gremlin_python/driver/protocol.py", line 83, in data_received
    message = self._message_serializer.deserialize_message(message)
  File "/Users/connor.skennerton/.pyenv/versions/dogma/lib/python3.6/site-packages/gremlin_python/driver/serializer.py", line 163, in deserialize_message
    return self._graphson_reader.toObject(msg)
  File "/Users/connor.skennerton/.pyenv/versions/dogma/lib/python3.6/site-packages/gremlin_python/structure/io/graphsonV3d0.py", line 129, in toObject
    return dict((self.toObject(k), self.toObject(v)) for k, v in obj.items())
  File "/Users/connor.skennerton/.pyenv/versions/dogma/lib/python3.6/site-packages/gremlin_python/structure/io/graphsonV3d0.py", line 129, in <genexpr>
    return dict((self.toObject(k), self.toObject(v)) for k, v in obj.items())
  File "/Users/connor.skennerton/.pyenv/versions/dogma/lib/python3.6/site-packages/gremlin_python/structure/io/graphsonV3d0.py", line 129, in toObject
    return dict((self.toObject(k), self.toObject(v)) for k, v in obj.items())
  File "/Users/connor.skennerton/.pyenv/versions/dogma/lib/python3.6/site-packages/gremlin_python/structure/io/graphsonV3d0.py", line 129, in <genexpr>
    return dict((self.toObject(k), self.toObject(v)) for k, v in obj.items())
  File "/Users/connor.skennerton/.pyenv/versions/dogma/lib/python3.6/site-packages/gremlin_python/structure/io/graphsonV3d0.py", line 126, in toObject
    return self.deserializers[obj[GraphSONUtil.TYPE_KEY]].objectify(obj[GraphSONUtil.VALUE_KEY], self)
  File "/Users/connor.skennerton/.pyenv/versions/dogma/lib/python3.6/site-packages/gremlin_python/structure/io/graphsonV3d0.py", line 432, in objectify
    new_list.append(reader.toObject(obj))
  File "/Users/connor.skennerton/.pyenv/versions/dogma/lib/python3.6/site-packages/gremlin_python/structure/io/graphsonV3d0.py", line 126, in toObject
    return self.deserializers[obj[GraphSONUtil.TYPE_KEY]].objectify(obj[GraphSONUtil.VALUE_KEY], self)
  File "/Users/connor.skennerton/.pyenv/versions/dogma/lib/python3.6/site-packages/gremlin_python/structure/io/graphsonV3d0.py", line 269, in objectify
    return Traverser(reader.toObject(d["value"]),
  File "/Users/connor.skennerton/.pyenv/versions/dogma/lib/python3.6/site-packages/gremlin_python/structure/io/graphsonV3d0.py", line 126, in toObject
    return self.deserializers[obj[GraphSONUtil.TYPE_KEY]].objectify(obj[GraphSONUtil.VALUE_KEY], self)
  File "/Users/connor.skennerton/.pyenv/versions/dogma/lib/python3.6/site-packages/gremlin_python/structure/io/graphsonV3d0.py", line 484, in objectify
    new_dict[reader.toObject(l[x])] = reader.toObject(l[x + 1])
TypeError: unhashable type: 'list'

Converting the list to a tuple would allow python to use these values as dictionary keys