bugfix isolation of derivatives for @extend_schema_serializer/@extend…

…_schema_field #585

drf_spectacular/drainage.py

@@ -101,6 +101,8 @@ def get_override(obj, prop, default=None):
 def set_override(obj, prop, value):
     if not hasattr(obj, '_spectacular_annotation'):
         obj._spectacular_annotation = {}
+    elif '_spectacular_annotation' not in obj.__dict__:
+        obj._spectacular_annotation = obj._spectacular_annotation.copy()
     obj._spectacular_annotation[prop] = value
     return obj
 

tests/test_regressions.py

@@ -2753,3 +2753,29 @@ def view_func(request, format=None):
         'wo': {'type': 'string', 'writeOnly': True, 'minLength': 1},
         'rw': {'type': 'string', 'minLength': 1}
     }
+
+
+def test_extend_schema_serializer_isolation(no_warnings):
+    @extend_schema_serializer(component_name='ABC')
+    class OneSerializer(serializers.Serializer):
+        pass
+
+    @extend_schema_serializer(component_name='XYZ')
+    class TwoSerializer(OneSerializer):
+        pass
+
+    assert OneSerializer._spectacular_annotation == {'component_name': 'ABC'}
+    assert TwoSerializer._spectacular_annotation == {'component_name': 'XYZ'}
+
+
+def test_extend_schema_field_isolation(no_warnings):
+    @extend_schema_field(field=OpenApiTypes.FLOAT)
+    class OneField(serializers.IntegerField):
+        pass
+
+    @extend_schema_field(field=OpenApiTypes.DOUBLE)
+    class TwoField(OneField):
+        pass
+
+    assert OneField._spectacular_annotation['field'] == OpenApiTypes.FLOAT
+    assert TwoField._spectacular_annotation['field'] == OpenApiTypes.DOUBLE