Fix KeyError @ fields to JSON:API schema rendering

Author: alida

starlette_jsonapi/openapi.py

@@ -96,6 +96,7 @@ def fields2jsonschema(self, fields, *, ordered=False, partial=None):
         for field_name, field_obj in fields.items():
             observed_field_name = field_obj.data_key or field_name
             prop = self.field2property(field_obj)
+
             if observed_field_name == 'id':
                 properties[observed_field_name] = prop
             elif isinstance(field_obj, JSONAPIRelationship):
@@ -111,9 +112,11 @@ def fields2jsonschema(self, fields, *, ordered=False, partial=None):
                     is_collection(partial) and field_name not in partial
                 ):
                     if isinstance(field_obj, JSONAPIRelationship):
-                        properties['relationships'].setdefault('required', []).append(observed_field_name)
+                        properties['relationships'].setdefault('required', [])
+                        properties['relationships']['required'].append(observed_field_name)
                     else:
-                        properties['attributes'].setdefault('required', []).append(observed_field_name)
+                        properties['attributes'].setdefault('required', [])
+                        properties['attributes']['required'].append(observed_field_name)
 
         jsonschema['required'] = ['type']
         if 'attributes' in properties and 'required' in properties['attributes']: