add mapping types

fastapi/_compat.py

@@ -43,6 +43,14 @@ sequence_annotation_to_type = {
 
 sequence_types = tuple(sequence_annotation_to_type.keys())
 
+mapping_annotation_to_type = {
+    Mapping: list,
+    List: list,
+}
+
+mapping_types = tuple(mapping_annotation_to_type.keys())
+
+
 if PYDANTIC_V2:
     from pydantic import PydanticSchemaGenerationError as PydanticSchemaGenerationError
     from pydantic import TypeAdapter
@@ -229,10 +237,10 @@ if PYDANTIC_V2:
         return field_annotation_is_scalar_sequence(field.field_info.annotation)
 
     def is_scalar_sequence_mapping_field(field: ModelField) -> bool:
-        return field_annotation_is_scalar_sequence(field.field_info.annotation)
+        return field_annotation_is_scalar_sequence_mapping(field.field_info.annotation)
 
     def is_scalar_mapping_field(field: ModelField) -> bool:
-        return field_annotation_is_scalar_sequence(field.field_info.annotation)
+        return field_annotation_is_scalar_mapping(field.field_info.annotation)
 
     def is_bytes_field(field: ModelField) -> bool:
         return is_bytes_or_nonable_bytes_annotation(field.type_)
@@ -559,6 +567,15 @@ 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(
+        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]
@@ -566,7 +583,7 @@ def value_is_sequence(value: Any) -> bool:
 
 def _annotation_is_complex(annotation: Union[Type[Any], None]) -> bool:
     return (
-        lenient_issubclass(annotation, (BaseModel, Mapping, UploadFile))
+        lenient_issubclass(annotation, (BaseModel, UploadFile))
         or _annotation_is_sequence(annotation)
         or is_dataclass(annotation)
     )
@@ -606,6 +623,37 @@ 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:
+        at_least_one_scalar_mapping = False
+        for arg in get_args(annotation):
+            if field_annotation_is_scalar_mapping(arg):
+                at_least_one_scalar_mapping = True
+                continue
+            elif not field_annotation_is_scalar(arg):
+                return False
+        return at_least_one_scalar_mapping
+    return field_annotation_is_mapping(annotation) and all(
+        field_annotation_is_scalar(sub_annotation)
+        for sub_annotation in get_args(annotation)
+    )
+
+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
+        for arg in get_args(annotation):
+            if field_annotation_is_scalar_mapping(arg):
+                at_least_one_scalar_mapping = True
+                continue
+            elif not field_annotation_is_scalar(arg):
+                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))
+        for sub_annotation in get_args(annotation)
+    )
 
 def is_bytes_or_nonable_bytes_annotation(annotation: Any) -> bool:
     if lenient_issubclass(annotation, bytes):