Fix reverse o2o relation resolution

graphene_django/debug/tests/test_query.py

@@ -50,9 +50,7 @@ def resolve_reporter(self, info, **args):
     """
     expected = {
         "reporter": {"lastName": "ABA"},
-        "_debug": {
-            "sql": [{"rawSql": str(Reporter.objects.order_by("pk")[:1].query)}]
-        },
+        "_debug": {"sql": [{"rawSql": str(Reporter.objects.order_by("pk")[:1].query)}]},
     }
     schema = graphene.Schema(query=Query)
     result = schema.execute(

graphene_django/tests/test_query.py

@@ -226,6 +226,66 @@ def resolve_reporter(self, info):
     assert result.data == expected
 
 
+def test_should_query_onetoone_fields():
+    film = Film(id=1)
+    film_details = FilmDetails(id=1, film=film)
+
+    class FilmNode(DjangoObjectType):
+        class Meta:
+            model = Film
+            interfaces = (Node,)
+
+    class FilmDetailsNode(DjangoObjectType):
+        class Meta:
+            model = FilmDetails
+            interfaces = (Node,)
+
+    class Query(graphene.ObjectType):
+        film = graphene.Field(FilmNode)
+        film_details = graphene.Field(FilmDetailsNode)
+
+        def resolve_film(root, info):
+            return film
+
+        def resolve_film_details(root, info):
+            return film_details
+
+    query = """
+        query FilmQuery {
+          filmDetails {
+            id
+            film {
+              id
+            }
+          }
+          film {
+            id
+            details {
+              id
+            }
+          }
+        }
+    """
+    expected = {
+        "filmDetails": {
+            "id": "RmlsbURldGFpbHNOb2RlOjE=",
+            "film": {
+                "id": "RmlsbU5vZGU6MQ=="
+            }
+        },
+        "film": {
+            "id": "RmlsbU5vZGU6MQ==",
+            "details": {
+                "id": "RmlsbURldGFpbHNOb2RlOjE="
+            }
+        },
+    }
+    schema = graphene.Schema(query=Query)
+    result = schema.execute(query)
+    assert not result.errors
+    assert result.data == expected
+
+
 def test_should_query_connectionfields():
     class ReporterType(DjangoObjectType):
         class Meta:

graphene_django/utils/utils.py

@@ -18,7 +18,8 @@ def get_reverse_fields(model, local_field_names):
         if name in local_field_names:
             continue
 
-        related = getattr(attr, "rel", None)
+        # "rel" for FK and M2M relations and "related" for O2O Relations
+        related = getattr(attr, "rel", None) or getattr(attr, "related", None)
         if isinstance(related, models.ManyToOneRel):
             yield (name, related)
         elif isinstance(related, models.ManyToManyRel) and not related.symmetrical: