Openapi document with dependecies override with Pydantic V2

fastapi/_compat.py

@@ -161,7 +161,21 @@ if PYDANTIC_V2:
         def __hash__(self) -> int:
             # Each ModelField is unique for our purposes, to allow making a dict from
             # ModelField to its JSON Schema.
-            return id(self)
+            # build a hash from the field_info and name and mode
+            # This method is probably not safe enough... but how can
+            # we easily hash and compare ModelFields builds with the same data?
+            return hash(
+                (
+                    repr(self.field_info),
+                    self.name,
+                    self.mode,
+                )
+            )
+
+        def __eq__(self, other: Any) -> bool:
+            if not isinstance(other, ModelField):
+                return False
+            return self.__hash__() == other.__hash__()
 
     def get_annotation_from_field_info(
         annotation: Any, field_info: FieldInfo, field_name: str

fastapi/openapi/utils.py

@@ -461,6 +461,17 @@ def get_fields_from_routes(
             if route.callbacks:
                 callback_flat_models.extend(get_fields_from_routes(route.callbacks))
             params = get_flat_params(route.dependant)
+            dependency_overrides = None
+            if route.dependency_overrides_provider:
+                dependency_overrides = (
+                    route.dependency_overrides_provider.dependency_overrides
+                )
+            dependant = get_resolved_dependant(
+                dependant=route.dependant,
+                dependency_overrides=dependency_overrides,
+            )
+            params.extend(get_flat_params(dependant))
+
             request_fields_from_routes.extend(params)
 
     flat_models = callback_flat_models + list(

tests/test_dependency_overrides_openapi.py

@@ -45,7 +45,10 @@ override_simple_openapi_schema = {
                 "parameters": [
                     {
                         "required": False,
-                        "schema": {"title": "Q", "type": "string"},
+                        "schema": {
+                            "anyOf": [{"type": "string"}, {"type": "null"}],
+                            "title": "Q",
+                        },
                         "name": "q",
                         "in": "query",
                     },