Fix (#1079) crash when generating schema for field with UUID choices.

The crash was fixed by replacing the JSON encoder used to hash elements
for enum deduplication with DRF JSON encoder which is capable of handling
type outside of the usual JSON standard types.

drf_spectacular/plumbing.py

@@ -37,6 +37,7 @@
 from rest_framework.fields import empty
 from rest_framework.settings import api_settings
 from rest_framework.test import APIRequestFactory
+from rest_framework.utils.encoders import JSONEncoder
 from rest_framework.utils.mediatypes import _MediaType
 from rest_framework.utils.serializer_helpers import ReturnDict, ReturnList
 from uritemplate import URITemplate
@@ -839,7 +840,7 @@ def load_enum_name_overrides():
 
 
 def list_hash(lst):
-    return hashlib.sha256(json.dumps(list(lst), sort_keys=True).encode()).hexdigest()
+    return hashlib.sha256(json.dumps(list(lst), sort_keys=True, cls=JSONEncoder).encode()).hexdigest()
 
 
 def anchor_pattern(pattern: str) -> str:

tests/test_postprocessing.py

@@ -314,3 +314,29 @@ def get(self, request):
         'items': {'$ref': '#/components/schemas/QualityLevelsEnum'},
         'readOnly': True
     }
+
+
+def test_uuid_choices(no_warnings):
+
+    import uuid
+
+    class XSerializer(serializers.Serializer):
+        foo = serializers.ChoiceField(
+            choices=[
+                (uuid.UUID('93d7527f-de3c-4a76-9cc2-5578675630d4'), 'baz'),
+                (uuid.UUID('47a4b873-409e-4e43-81d5-fafc3faeb849'), 'bar')
+            ]
+        )
+
+    class XAPIView(APIView):
+        @extend_schema(responses=XSerializer)
+        def get(self, request):
+            pass  # pragma: no cover
+
+    schema = generate_schema('x', view=XAPIView)
+
+    assert 'FooEnum' in schema['components']['schemas']
+    assert schema['components']['schemas']['FooEnum']['enum'] == [
+        uuid.UUID('93d7527f-de3c-4a76-9cc2-5578675630d4'),
+        uuid.UUID('47a4b873-409e-4e43-81d5-fafc3faeb849')
+    ]