handle Map[scalar, List[scalar]] and Map[scalar, scalar] sepaeratly

fastapi/dependencies/utils.py

@@ -257,9 +257,22 @@ def is_scalar_mapping_field(field: ModelField) -> bool:
         if field.sub_fields is None:
             return True
         for sub_field in field.sub_fields:
-            if (not is_scalar_field(sub_field)) and (
-                not is_scalar_sequence_field(sub_field)
-            ):
+            if not is_scalar_field(sub_field):
+                return False
+        return True
+    if lenient_issubclass(field.type_, mapping_types):
+        return True
+    return False
+
+
+def is_scalar_sequence_mapping_field(field: ModelField) -> bool:
+    if (field.shape in mapping_shapes) and not lenient_issubclass(
+        field.type_, BaseModel
+    ):
+        if field.sub_fields is None:
+            return True
+        for sub_field in field.sub_fields:
+            if not is_scalar_sequence_field(sub_field):
                 return False
         return True
     if lenient_issubclass(field.type_, mapping_types):
@@ -349,6 +362,7 @@ def get_dependant(
         elif isinstance(param.default, (params.Query, params.Header)) and (
             is_scalar_sequence_field(param_field)
             or is_scalar_mapping_field(param_field)
+            or is_scalar_sequence_mapping_field(param_field)
         ):
             add_param_to_fields(field=param_field, dependant=dependant)
         else:
@@ -628,10 +642,15 @@ def request_params_to_args(
             value = received_params.getlist(field.alias) or field.default
         elif is_scalar_mapping_field(field) and isinstance(
             received_params, (QueryParams,)
+        ):
+            value = dict(received_params.multi_items())
+        elif is_scalar_sequence_mapping_field(field) and isinstance(
+            received_params, (QueryParams,)
         ):
             value = defaultdict(list)
             for key, field_value in received_params.multi_items():
                 value[key].append(field_value)
+            value = dict(value)
         else:
             value = received_params.get(field.alias)
         field_info = field.field_info