What in my code is causing TypeError: Bad source for traversal

[agenovia]

Just started using neomodel and I've been going over the Relationships documentation. I played around with the examples given (both sync and async, and converting sync examples to async to see that it all still works) and thought I understood it enough. However, trying to apply it using the model below produces an ambiguous error.

How come this code:

from neomodel import (
    AsyncRelationshipFrom,
    AsyncRelationshipTo,
    AsyncStructuredNode,
    AsyncStructuredRel,
    DateProperty,
    One,
    StringProperty,
    UniqueIdProperty,
)


class MemberRelationship(AsyncStructuredRel):
    since = DateProperty()


class User(AsyncStructuredNode):
    uuid = StringProperty(required=True, unique_index=True)
    member_of = AsyncRelationshipTo("Team", "MEMBER_OF", model=MemberRelationship)
    owns = AsyncRelationshipTo("Team", "OWNS", cardinality=One)


class Team(AsyncStructuredNode):
    uuid = UniqueIdProperty()
    name = StringProperty(required=True)
    owner = AsyncRelationshipFrom("User", "OWNS", cardinality=One)


user = await User(uuid="725223cd-31f8-4800-8515-4c16184df189").save()
team = await Team(name="My Team").save()
await user.owns.connect(team)

Produces TypeError: Bad source for traversal: <class '__main__.User'>:

---------------------------------------------------------------------------
TypeError                                 Traceback (most recent call last)
Cell In[3], line 32
     30 user = await User(uuid="725223cd-31f8-4800-8515-4c16184df189").save()
     31 team = await Team(name="My Team").save()
---> 32 await user.owns.connect(team)

File [~/anaconda3/envs/neo4j-testing/lib/python3.12/site-packages/neomodel/sync_/cardinality.py:142](http://localhost:8888/home/w/anaconda3/envs/neo4j-testing/lib/python3.12/site-packages/neomodel/sync_/cardinality.py#line=141), in One.connect(self, node, properties)
    140 if not hasattr(self.source, "element_id") or self.source.element_id is None:
    141     raise ValueError("Node has not been saved cannot connect!")
--> 142 if super().__len__():
    143     raise AttemptedCardinalityViolation("Node already has one relationship")
    144 return super().connect(node, properties)

File [~/anaconda3/envs/neo4j-testing/lib/python3.12/site-packages/neomodel/sync_/relationship_manager.py:391](http://localhost:8888/home/w/anaconda3/envs/neo4j-testing/lib/python3.12/site-packages/neomodel/sync_/relationship_manager.py#line=390), in RelationshipManager.__len__(self)
    390 def __len__(self) -> int:
--> 391     return self._new_traversal().__len__()

File [~/anaconda3/envs/neo4j-testing/lib/python3.12/site-packages/neomodel/sync_/relationship_manager.py:31](http://localhost:8888/home/w/anaconda3/envs/neo4j-testing/lib/python3.12/site-packages/neomodel/sync_/relationship_manager.py#line=30), in check_source.<locals>.checker(self, *args, **kwargs)
     28 @functools.wraps(fn)
     29 def checker(self: Any, *args: Any, **kwargs: Any) -> Callable:
     30     self.source._pre_action_check(self.name + "." + fn_name)
---> 31     return fn(self, *args, **kwargs)

File [~/anaconda3/envs/neo4j-testing/lib/python3.12/site-packages/neomodel/sync_/relationship_manager.py:300](http://localhost:8888/home/w/anaconda3/envs/neo4j-testing/lib/python3.12/site-packages/neomodel/sync_/relationship_manager.py#line=299), in RelationshipManager._new_traversal(self)
    298 @check_source
    299 def _new_traversal(self) -> Traversal:
--> 300     return Traversal(self.source, self.name, self.definition)

File [~/anaconda3/envs/neo4j-testing/lib/python3.12/site-packages/neomodel/sync_/match.py:1711](http://localhost:8888/home/w/anaconda3/envs/neo4j-testing/lib/python3.12/site-packages/neomodel/sync_/match.py#line=1710), in Traversal.__init__(self, source, name, definition)
   1709     self.source_class = source.source_class
   1710 else:
-> 1711     raise TypeError(f"Bad source for traversal: {type(source)}")
   1713 invalid_keys = set(definition) - {
   1714     "direction",
   1715     "model",
   1716     "node_class",
   1717     "relation_type",
   1718 }
   1719 if invalid_keys:

TypeError: Bad source for traversal: <class '__main__.User'>

What am I doing wrong?

[agenovia]

I figured it out. I was using neomodel.One in my code when I should have used AsyncOne.

As everything is using the async version, the cardinality has to as well. The following code works now.

from neomodel import (
    AsyncRelationshipFrom,
    AsyncRelationshipTo,
    AsyncStructuredNode,
    AsyncStructuredRel,
    DateProperty,
    AsyncOne,
    StringProperty,
    UniqueIdProperty,
)


class MemberRelationship(AsyncStructuredRel):
    since = DateProperty()


class User(AsyncStructuredNode):
    uuid = StringProperty(required=True, unique_index=True)
    member_of = AsyncRelationshipTo("Team", "MEMBER_OF", model=MemberRelationship)
    owns = AsyncRelationshipTo("Team", "OWNS", cardinality=AsyncOne)


class Team(AsyncStructuredNode):
    uuid = UniqueIdProperty()
    name = StringProperty(required=True)
    owner = AsyncRelationshipFrom("User", "OWNS", cardinality=AsyncOne)


user = await User(uuid="725223cd-31f8-4800-8515-4c16184df189").save()
team = await Team(name="My Team").save()
await user.owns.connect(team)