Add flag for using enum names or members as values (#73)

src/graphql/type/definition.py

@@ -1091,14 +1091,18 @@ def assert_union_type(type_: Any) -> GraphQLUnionType:
 
 class GraphQLEnumTypeKwargs(GraphQLNamedTypeKwargs, total=False):
     values: GraphQLEnumValueMap
+    names_as_values: Optional[bool]
 
 
 class GraphQLEnumType(GraphQLNamedType):
     """Enum Type Definition
 
     Some leaf values of requests and input values are Enums. GraphQL serializes Enum
     values as strings, however internally Enums can be represented by any kind of type,
-    often integers. They can also be provided as a Python Enum.
+    often integers. They can also be provided as a Python Enum. In this case, the flag
+    `names_as_values` determines what will be used as internal representation. The
+    default value of `False` will use the enum values, the value `True` will use the
+    enum names, and the value `None` will use the members themselves.
 
     Example::
 
@@ -1132,6 +1136,7 @@ def __init__(
         self,
         name: str,
         values: Union[GraphQLEnumValueMap, Mapping[str, Any], Type[Enum]],
+        names_as_values: Optional[bool] = False,
         description: Optional[str] = None,
         extensions: Optional[Dict[str, Any]] = None,
         ast_node: Optional[EnumTypeDefinitionNode] = None,
@@ -1158,10 +1163,13 @@ def __init__(
                         f"{name} values must be an Enum or a mapping"
                         " with value names as keys."
                     )
-            values = cast(Dict, values)
+            values = cast(Dict[str, Any], values)
         else:
-            values = cast(Dict, values)
-            values = {key: value.value for key, value in values.items()}
+            values = cast(Dict[str, Enum], values)
+            if names_as_values is False:
+                values = {key: value.value for key, value in values.items()}
+            elif names_as_values is True:
+                values = {key: key for key in values}
         values = {
             assert_enum_value_name(key): value
             if isinstance(value, GraphQLEnumValue)

tests/type/test_definition.py

@@ -1,3 +1,4 @@
+from enum import Enum
 from math import isnan, nan
 from typing import cast, Dict
 
@@ -1057,6 +1058,50 @@ def rejects_a_union_type_with_incorrect_extension_ast_nodes():
 
 
 def describe_type_system_enums():
+    def defines_an_enum_using_a_dict():
+        enum_type = GraphQLEnumType("SomeEnum", {"RED": 1, "BLUE": 2})
+        assert enum_type.values == {
+            "RED": GraphQLEnumValue(1),
+            "BLUE": GraphQLEnumValue(2),
+        }
+
+    def defines_an_enum_using_an_enum_value_map():
+        red, blue = GraphQLEnumValue(1), GraphQLEnumValue(2)
+        enum_type = GraphQLEnumType("SomeEnum", {"RED": red, "BLUE": blue})
+        assert enum_type.values == {"RED": red, "BLUE": blue}
+
+    def defines_an_enum_using_a_python_enum():
+        colors = Enum("Colors", "RED BLUE")
+        enum_type = GraphQLEnumType("SomeEnum", colors)
+        assert enum_type.values == {
+            "RED": GraphQLEnumValue(1),
+            "BLUE": GraphQLEnumValue(2),
+        }
+
+    def defines_an_enum_using_values_of_a_python_enum():
+        colors = Enum("Colors", "RED BLUE")
+        enum_type = GraphQLEnumType("SomeEnum", colors, names_as_values=False)
+        assert enum_type.values == {
+            "RED": GraphQLEnumValue(1),
+            "BLUE": GraphQLEnumValue(2),
+        }
+
+    def defines_an_enum_using_names_of_a_python_enum():
+        colors = Enum("Colors", "RED BLUE")
+        enum_type = GraphQLEnumType("SomeEnum", colors, names_as_values=True)
+        assert enum_type.values == {
+            "RED": GraphQLEnumValue("RED"),
+            "BLUE": GraphQLEnumValue("BLUE"),
+        }
+
+    def defines_an_enum_using_members_of_a_python_enum():
+        colors = Enum("Colors", "RED BLUE")
+        enum_type = GraphQLEnumType("SomeEnum", colors, names_as_values=None)
+        assert enum_type.values == {
+            "RED": GraphQLEnumValue(colors.RED),
+            "BLUE": GraphQLEnumValue(colors.BLUE),
+        }
+
     def defines_an_enum_type_with_a_description():
         description = "nice enum"
         enum_type = GraphQLEnumType(