tests passing for freeform queries

fastapi/_compat.py

@@ -45,7 +45,6 @@ sequence_types = tuple(sequence_annotation_to_type.keys())
 
 mapping_annotation_to_type = {
     Mapping: list,
-    List: list,
 }
 
 mapping_types = tuple(mapping_annotation_to_type.keys())
@@ -567,16 +566,19 @@ def field_annotation_is_sequence(annotation: Union[Type[Any], None]) -> bool:
         get_origin(annotation)
     )
 
+
 def _annotation_is_mapping(annotation: Union[Type[Any], None]) -> bool:
     if lenient_issubclass(annotation, (str, bytes)):
         return False
     return lenient_issubclass(annotation, mapping_types)
 
+
 def field_annotation_is_mapping(annotation: Union[Type[Any], None]) -> bool:
-    return _annotation_is_mapping(annotation) or _annotation_is_sequence(
+    return _annotation_is_mapping(annotation) or _annotation_is_mapping(
         get_origin(annotation)
     )
 
+
 def value_is_sequence(value: Any) -> bool:
     return isinstance(value, sequence_types) and not isinstance(value, (str, bytes))  # type: ignore[arg-type]
 
@@ -585,6 +587,7 @@ def _annotation_is_complex(annotation: Union[Type[Any], None]) -> bool:
     return (
         lenient_issubclass(annotation, (BaseModel, UploadFile))
         or _annotation_is_sequence(annotation)
+        or _annotation_is_mapping(annotation)
         or is_dataclass(annotation)
     )
 
@@ -623,6 +626,7 @@ def field_annotation_is_scalar_sequence(annotation: Union[Type[Any], None]) -> b
         for sub_annotation in get_args(annotation)
     )
 
+
 def field_annotation_is_scalar_mapping(annotation: Union[Type[Any], None]) -> bool:
     origin = get_origin(annotation)
     if origin is Union or origin is UnionType:
@@ -639,7 +643,10 @@ def field_annotation_is_scalar_mapping(annotation: Union[Type[Any], None]) -> bo
         for sub_annotation in get_args(annotation)
     )
 
-def field_annotation_is_scalar_sequence_mapping(annotation: Union[Type[Any], None]) -> bool:
+
+def field_annotation_is_scalar_sequence_mapping(
+    annotation: Union[Type[Any], None]
+) -> bool:
     origin = get_origin(annotation)
     if origin is Union or origin is UnionType:
         at_least_one_scalar_mapping = False
@@ -651,10 +658,14 @@ def field_annotation_is_scalar_sequence_mapping(annotation: Union[Type[Any], Non
                 return False
         return at_least_one_scalar_mapping
     return field_annotation_is_mapping(annotation) and all(
-        (field_annotation_is_scalar_sequence(sub_annotation) or field_annotation_is_scalar(sub_annotation))
+        (
+            field_annotation_is_scalar_sequence(sub_annotation)
+            or field_annotation_is_scalar(sub_annotation)
+        )
         for sub_annotation in get_args(annotation)
     )
 
+
 def is_bytes_or_nonable_bytes_annotation(annotation: Any) -> bool:
     if lenient_issubclass(annotation, bytes):
         return True

fastapi/dependencies/utils.py

@@ -652,7 +652,7 @@ def request_params_to_args(
             received_params, (QueryParams, Headers)
         ):
             value = received_params.getlist(field.alias) or field.default
-        if is_scalar_mapping_field(field) and isinstance(
+        elif is_scalar_mapping_field(field) and isinstance(
             received_params, (QueryParams, Headers)
         ):
             value = dict(received_params.multi_items()) or field.default

tests/main.py

@@ -184,16 +184,21 @@ def get_query_param_required_type(query: int = Query()):
     return f"foo bar {query}"
 
 
-@app.get("/query/params")
-def get_query_params(query: Mapping[str, int] = Query({})):
-    return f"foo bar {query}"
-
-
 @app.get("/query/sequence-params")
 def get_sequence_query_params(query: Mapping[str, List[int]] = Query({})):
     return f"foo bar {query}"
 
 
+@app.get("/query/mapping-params")
+def get_mapping_query_params(queries: Mapping[str, str] = Query({})):
+    return f"foo bar {queries['foo']} {queries['bar']}"
+
+
+@app.get("/query/mapping-sequence-params")
+def get_sequence_mapping_query_params(queries: Mapping[str, List[int]] = Query({})):
+    return f"foo bar {queries}"
+
+
 @app.get("/enum-status-code", status_code=http.HTTPStatus.CREATED)
 def get_enum_status_code():
     return "foo bar"

tests/test_query.py

@@ -408,3 +408,9 @@ def test_query_frozenset_query_1_query_1_query_2():
     response = client.get("/query/frozenset/?query=1&query=1&query=2")
     assert response.status_code == 200
     assert response.json() == "1,2"
+
+
+def test_mapping_query():
+    response = client.get("/query/mapping-params/?foo=fuzz&bar=buzz")
+    assert response.status_code == 200
+    assert response.json() == "foo bar fuzz buzz"