account for functools.partial wrapped type hints #451

drf_spectacular/contrib/django_filters.py

@@ -1,12 +1,10 @@
-import typing
-
 from django.db import models
 
 from drf_spectacular.drainage import warn
 from drf_spectacular.extensions import OpenApiFilterExtension
 from drf_spectacular.plumbing import (
-    build_array_type, build_basic_type, build_parameter_type, follow_field_source, get_view_model,
-    is_basic_type,
+    build_array_type, build_basic_type, build_parameter_type, follow_field_source, get_type_hints,
+    get_view_model, is_basic_type,
 )
 from drf_spectacular.types import OpenApiTypes
 from drf_spectacular.utils import OpenApiParameter
@@ -167,7 +165,7 @@ def _build_filter_method_type(self, filterset_class, filter_field):
             filter_method = getattr(filterset_class, filter_field.method)
 
         try:
-            filter_method_hints = typing.get_type_hints(filter_method)
+            filter_method_hints = get_type_hints(filter_method)
         except:  # noqa: E722
             filter_method_hints = {}
 

drf_spectacular/drainage.py

@@ -1,4 +1,5 @@
 import contextlib
+import functools
 import sys
 from collections import defaultdict
 from typing import DefaultDict
@@ -70,6 +71,8 @@ def _get_current_trace():
 
 
 def has_override(obj, prop):
+    if isinstance(obj, functools.partial):
+        obj = obj.func
     if not hasattr(obj, '_spectacular_annotation'):
         return False
     if prop not in obj._spectacular_annotation:
@@ -78,6 +81,8 @@ def has_override(obj, prop):
 
 
 def get_override(obj, prop, default=None):
+    if isinstance(obj, functools.partial):
+        obj = obj.func
     if not has_override(obj, prop):
         return default
     return obj._spectacular_annotation[prop]

drf_spectacular/openapi.py

@@ -27,9 +27,9 @@
     ComponentRegistry, ResolvedComponent, UnableToProceedError, append_meta, build_array_type,
     build_basic_type, build_choice_field, build_examples_list, build_media_type_object,
     build_object_type, build_parameter_type, error, follow_field_source, force_instance, get_doc,
-    get_view_model, is_basic_type, is_field, is_list_serializer, is_patched_serializer,
-    is_serializer, is_trivial_string_variation, resolve_regex_path_parameter, resolve_type_hint,
-    safe_ref, warn,
+    get_type_hints, get_view_model, is_basic_type, is_field, is_list_serializer,
+    is_patched_serializer, is_serializer, is_trivial_string_variation, resolve_regex_path_parameter,
+    resolve_type_hint, safe_ref, warn,
 )
 from drf_spectacular.settings import spectacular_settings
 from drf_spectacular.types import OpenApiTypes, build_generic_type
@@ -828,7 +828,7 @@ def _map_field_validators(self, field, schema):
                     schema['minimum'] = -schema['maximum']
 
     def _map_response_type_hint(self, method):
-        hint = get_override(method, 'field') or typing.get_type_hints(method).get('return')
+        hint = get_override(method, 'field') or get_type_hints(method).get('return')
 
         if is_serializer(hint) or is_field(hint):
             return self._map_serializer_field(force_instance(hint), 'response')

drf_spectacular/plumbing.py

@@ -1,4 +1,5 @@
 import collections
+import functools
 import hashlib
 import inspect
 import json
@@ -164,6 +165,13 @@ def safe_index(lst, item):
     return ''
 
 
+def get_type_hints(obj):
+    """ unpack wrapped partial object and use actual func object """
+    if isinstance(obj, functools.partial):
+        obj = obj.func
+    return typing.get_type_hints(obj)
+
+
 def build_basic_type(obj):
     """
     resolve either enum or actual type and yield schema template for modification
@@ -409,7 +417,7 @@ def _follow_field_source(model, path: List[str]):
 
 
 def _follow_return_type(a_callable):
-    target_type = typing.get_type_hints(a_callable).get('return')
+    target_type = get_type_hints(a_callable).get('return')
     if target_type is None:
         return target_type
     origin, args = _get_type_hint_origin(target_type)
@@ -929,8 +937,8 @@ def resolve_type_hint(hint):
         return build_basic_type(hint)
     elif origin is None and inspect.isclass(hint) and issubclass(hint, tuple):
         # a convoluted way to catch NamedTuple. suggestions welcome.
-        if typing.get_type_hints(hint):
-            properties = {k: resolve_type_hint(v) for k, v in typing.get_type_hints(hint).items()}
+        if get_type_hints(hint):
+            properties = {k: resolve_type_hint(v) for k, v in get_type_hints(hint).items()}
         else:
             properties = {k: build_basic_type(OpenApiTypes.ANY) for k in hint._fields}
         return build_object_type(properties=properties, required=properties.keys())
@@ -962,7 +970,7 @@ def resolve_type_hint(hint):
     elif hasattr(typing, 'TypedDict') and isinstance(hint, typing._TypedDictMeta):
         return build_object_type(
             properties={
-                k: resolve_type_hint(v) for k, v in typing.get_type_hints(hint).items()
+                k: resolve_type_hint(v) for k, v in get_type_hints(hint).items()
             }
         )
     elif origin is typing.Union:

tests/test_regressions.py

@@ -2,6 +2,7 @@
 import typing
 import uuid
 from decimal import Decimal
+from functools import partialmethod
 from unittest import mock
 
 import pytest
@@ -2024,3 +2025,30 @@ def get(self, request):
     assert get_response_schema(schema['paths']['/x/']['get'])['properties']['results'] == {
         'type': 'array', 'items': {'type': 'object', 'additionalProperties': {}}
     }
+
+
+def test_serializer_method_field_with_functools_partial():
+    class XSerializer(serializers.Serializer):
+        foo = serializers.SerializerMethodField()
+        bar = serializers.SerializerMethodField()
+
+        @extend_schema_field(OpenApiTypes.DATE)
+        def _private_method_foo(self, field, extra_param):
+            return 'foo'  # pragma: no cover
+
+        def _private_method_bar(self, field, extra_param) -> int:
+            return 1  # pragma: no cover
+
+        get_foo = partialmethod(_private_method_foo, extra_param='foo')
+        get_bar = partialmethod(_private_method_bar, extra_param='bar')
+
+    @extend_schema(request=XSerializer, responses=XSerializer)
+    @api_view(['POST'])
+    def view_func(request, format=None):
+        pass  # pragma: no cover
+
+    schema = generate_schema('/x/', view_function=view_func)
+    assert schema['components']['schemas']['X']['properties'] == {
+        'foo': {'type': 'string', 'format': 'date', 'readOnly': True},
+        'bar': {'type': 'integer', 'readOnly': True}
+    }