Preserve schema properties when sorting

Build the sorted schema from to_kwargs() so the description and other
properties are kept. The sorted schema now inherits assume_valid.

Author: Cito

src/graphql/utilities/lexicographic_sort_schema.py

@@ -169,20 +169,24 @@ def sort_named_type(type_: GraphQLNamedType) -> GraphQLNamedType:
     }
 
     return GraphQLSchema(
-        types=type_map.values(),
-        directives=[
-            sort_directive(directive)
-            for directive in sorted(schema.directives, key=sort_by_name_key)
-        ],
-        query=cast(Optional[GraphQLObjectType], replace_maybe_type(schema.query_type)),
-        mutation=cast(
-            Optional[GraphQLObjectType], replace_maybe_type(schema.mutation_type)
-        ),
-        subscription=cast(
-            Optional[GraphQLObjectType], replace_maybe_type(schema.subscription_type)
-        ),
-        extensions=schema.extensions,
-        ast_node=schema.ast_node,
+        **merge_kwargs(
+            schema.to_kwargs(),
+            types=type_map.values(),
+            directives=[
+                sort_directive(directive)
+                for directive in sorted(schema.directives, key=sort_by_name_key)
+            ],
+            query=cast(
+                Optional[GraphQLObjectType], replace_maybe_type(schema.query_type)
+            ),
+            mutation=cast(
+                Optional[GraphQLObjectType], replace_maybe_type(schema.mutation_type)
+            ),
+            subscription=cast(
+                Optional[GraphQLObjectType],
+                replace_maybe_type(schema.subscription_type),
+            ),
+        )
     )
 
 

tests/utilities/test_lexicographic_sort_schema.py

@@ -452,3 +452,24 @@ def preserves_input_field_out_name():
 
             assert sorted_input_type.fields["aField"].out_name == "a_field"
             assert sorted_input_type.fields["zField"].out_name == "z_field"
+
+    def describe_schema_properties():
+        def preserves_schema_description():
+            query_type = GraphQLObjectType(
+                "Query", {"dummy": GraphQLField(GraphQLString)}
+            )
+            schema = GraphQLSchema(
+                query=query_type, description="This is the schema description."
+            )
+            sorted_schema = lexicographic_sort_schema(schema)
+
+            assert sorted_schema.description == "This is the schema description."
+
+        def preserves_schema_extensions():
+            query_type = GraphQLObjectType(
+                "Query", {"dummy": GraphQLField(GraphQLString)}
+            )
+            schema = GraphQLSchema(query=query_type, extensions={"custom": "value"})
+            sorted_schema = lexicographic_sort_schema(schema)
+
+            assert sorted_schema.extensions == {"custom": "value"}