Add typing for print_ast function

Replicates graphql/graphql-js@213c8a7

Author: Cito

graphql/language/printer.py

@@ -8,7 +8,7 @@
 __all__ = ["print_ast"]
 
 
-def print_ast(ast: Node):
+def print_ast(ast: Node) -> str:
     """Convert an AST into a string.
 
     The conversion is done using a set of reasonable formatting rules.

graphql/language/visitor.py

@@ -190,7 +190,7 @@ class Stack(NamedTuple):
     prev: Any  # 'Stack' (python/mypy/issues/731)
 
 
-def visit(root: Node, visitor: Visitor, visitor_keys=None) -> Node:
+def visit(root: Node, visitor: Visitor, visitor_keys=None) -> Any:
     """Visit each node in an AST.
 
     `visit()` will walk through an AST using a depth first traversal, calling the

graphql/type/introspection.py

@@ -6,7 +6,6 @@
     GraphQLEnumType,
     GraphQLEnumValue,
     GraphQLField,
-    GraphQLInputType,
     GraphQLList,
     GraphQLNonNull,
     GraphQLObjectType,
@@ -21,9 +20,8 @@
     is_scalar_type,
     is_union_type,
 )
-from ..pyutils import is_invalid
 from .scalars import GraphQLBoolean, GraphQLString
-from ..language import DirectiveLocation
+from ..language import DirectiveLocation, print_ast
 
 __all__ = [
     "SchemaMetaFieldDef",
@@ -35,13 +33,6 @@
 ]
 
 
-def print_value(value: Any, type_: GraphQLInputType) -> str:
-    # Since print_value needs graphql.type, it can only be imported later
-    from ..utilities.schema_printer import print_value
-
-    return print_value(value, type_)
-
-
 __Schema: GraphQLObjectType = GraphQLObjectType(
     name="__Schema",
     description="A GraphQL Schema defines the capabilities of a GraphQL"
@@ -345,6 +336,14 @@ def of_type(type_, _info):
 )
 
 
+def _resolve_input_value_default_value(item, _info):
+    # Since ast_from_value needs graphql.type, it can only be imported later
+    from ..utilities import ast_from_value
+
+    value_ast = ast_from_value(item[1].default_value, item[1].type)
+    return print_ast(value_ast) if value_ast else None
+
+
 __InputValue: GraphQLObjectType = GraphQLObjectType(
     name="__InputValue",
     description="Arguments provided to Fields or Directives and the input"
@@ -364,9 +363,7 @@ def of_type(type_, _info):
             GraphQLString,
             description="A GraphQL-formatted string representing"
             " the default value for this input value.",
-            resolve=lambda item, _info: None
-            if is_invalid(item[1].default_value)
-            else print_value(item[1].default_value, item[1].type),
+            resolve=_resolve_input_value_default_value,
         ),
     },
 )

graphql/utilities/schema_printer.py

@@ -3,7 +3,7 @@
 from typing import Any, Callable, Dict, List, Optional, Union, cast
 
 from ..language import print_ast
-from ..pyutils import inspect, is_invalid, is_nullish
+from ..pyutils import inspect
 from ..type import (
     DEFAULT_DEPRECATION_REASON,
     GraphQLArgument,
@@ -248,9 +248,10 @@ def print_args(args: Dict[str, GraphQLArgument], indentation="") -> str:
 
 
 def print_input_value(name: str, arg: GraphQLArgument) -> str:
+    default_ast = ast_from_value(arg.default_value, arg.type)
     arg_decl = f"{name}: {arg.type}"
-    if not is_invalid(arg.default_value):
-        arg_decl += f" = {print_value(arg.default_value, arg.type)}"
+    if default_ast:
+        arg_decl += f" = {print_ast(default_ast)}"
     return arg_decl
 
 
@@ -268,10 +269,10 @@ def print_deprecated(field_or_enum_value: Union[GraphQLField, GraphQLEnumValue])
     if not field_or_enum_value.is_deprecated:
         return ""
     reason = field_or_enum_value.deprecation_reason
-    if is_nullish(reason) or reason == "" or reason == DEFAULT_DEPRECATION_REASON:
+    reason_ast = ast_from_value(reason, GraphQLString)
+    if not reason_ast or reason == "" or reason == DEFAULT_DEPRECATION_REASON:
         return " @deprecated"
-    else:
-        return f" @deprecated(reason: {print_value(reason, GraphQLString)})"
+    return f" @deprecated(reason: {print_ast(reason_ast)})"
 
 
 def print_description(

tests/utilities/test_build_ast_schema.py

@@ -3,7 +3,7 @@
 from pytest import raises
 
 from graphql import graphql_sync
-from graphql.language import parse, print_ast, DocumentNode
+from graphql.language import parse, print_ast, DocumentNode, Node
 from graphql.type import (
     GraphQLDeprecatedDirective,
     GraphQLIncludeDirective,
@@ -33,6 +33,11 @@ def cycle_sdl(sdl: str) -> str:
     return print_schema(schema)
 
 
+def print_node(node: Node) -> str:
+    assert node
+    return print_ast(node)
+
+
 def describe_schema_builder():
     def can_use_built_schema_for_limited_execution():
         schema = build_ast_schema(
@@ -704,7 +709,9 @@ def correctly_assign_ast_nodes():
             directive @test(arg: TestScalar) on FIELD
             """
         )
-        schema = build_schema(sdl)
+        ast = parse(sdl, no_location=True)
+
+        schema = build_ast_schema(ast)
         query = assert_object_type(schema.get_type("Query"))
         test_input = assert_input_object_type(schema.get_type("TestInput"))
         test_enum = assert_enum_type(schema.get_type("TestEnum"))
@@ -725,22 +732,23 @@ def correctly_assign_ast_nodes():
                 test_type.ast_node,
                 test_scalar.ast_node,
                 test_directive.ast_node,
-            ]
+            ],
+            loc=None,
         )
-        assert print_ast(restored_schema_ast) == sdl
+        assert restored_schema_ast == ast
 
         test_field = query.fields["testField"]
-        assert print_ast(test_field.ast_node) == (
+        assert print_node(test_field.ast_node) == (
             "testField(testArg: TestInput): TestUnion"
         )
-        assert print_ast(test_field.args["testArg"].ast_node) == "testArg: TestInput"
-        assert print_ast(test_input.fields["testInputField"].ast_node) == (
+        assert print_node(test_field.args["testArg"].ast_node) == "testArg: TestInput"
+        assert print_node(test_input.fields["testInputField"].ast_node) == (
             "testInputField: TestEnum"
         )
         test_enum_value = test_enum.values["TEST_VALUE"]
         assert test_enum_value
-        assert print_ast(test_enum_value.ast_node) == "TEST_VALUE"
-        assert print_ast(test_interface.fields["interfaceField"].ast_node) == (
+        assert print_node(test_enum_value.ast_node) == "TEST_VALUE"
+        assert print_node(test_interface.fields["interfaceField"].ast_node) == (
             "interfaceField: String"
         )
         assert print_ast(test_directive.args["arg"].ast_node) == "arg: TestScalar"

tests/utilities/test_extend_schema.py

@@ -1,7 +1,7 @@
 from pytest import raises
 
 from graphql import graphql_sync
-from graphql.language import parse, print_ast, DirectiveLocation, DocumentNode
+from graphql.language import parse, print_ast, DirectiveLocation, DocumentNode, Node
 from graphql.pyutils import dedent
 from graphql.type import (
     GraphQLArgument,
@@ -140,6 +140,11 @@ def print_test_schema_changes(extended_schema):
     return print_ast(ast)
 
 
+def print_node(node: Node) -> str:
+    assert node
+    return print_ast(node)
+
+
 def describe_extend_schema():
     def returns_the_original_schema_when_there_are_no_type_definitions():
         extended_schema = extend_test_schema("{ field }")
@@ -423,51 +428,53 @@ def correctly_assigns_ast_nodes_to_new_and_extended_types():
         ) == print_schema(extended_twice_schema)
 
         new_field = query.fields["newField"]
-        assert print_ast(new_field.ast_node) == "newField(testArg: TestInput): TestEnum"
-        assert print_ast(new_field.args["testArg"].ast_node) == "testArg: TestInput"
         assert (
-            print_ast(query.fields["oneMoreNewField"].ast_node)
+            print_node(new_field.ast_node) == "newField(testArg: TestInput): TestEnum"
+        )
+        assert print_node(new_field.args["testArg"].ast_node) == "testArg: TestInput"
+        assert (
+            print_node(query.fields["oneMoreNewField"].ast_node)
             == "oneMoreNewField: TestUnion"
         )
 
         new_value = some_enum.values["NEW_VALUE"]
         assert some_enum
-        assert print_ast(new_value.ast_node) == "NEW_VALUE"
+        assert print_node(new_value.ast_node) == "NEW_VALUE"
 
         one_more_new_value = some_enum.values["ONE_MORE_NEW_VALUE"]
         assert one_more_new_value
-        assert print_ast(one_more_new_value.ast_node) == "ONE_MORE_NEW_VALUE"
-        assert print_ast(some_input.fields["newField"].ast_node) == "newField: String"
+        assert print_node(one_more_new_value.ast_node) == "ONE_MORE_NEW_VALUE"
+        assert print_node(some_input.fields["newField"].ast_node) == "newField: String"
         assert (
-            print_ast(some_input.fields["oneMoreNewField"].ast_node)
+            print_node(some_input.fields["oneMoreNewField"].ast_node)
             == "oneMoreNewField: String"
         )
         assert (
-            print_ast(some_interface.fields["newField"].ast_node) == "newField: String"
+            print_node(some_interface.fields["newField"].ast_node) == "newField: String"
         )
         assert (
-            print_ast(some_interface.fields["oneMoreNewField"].ast_node)
+            print_node(some_interface.fields["oneMoreNewField"].ast_node)
             == "oneMoreNewField: String"
         )
 
         assert (
-            print_ast(test_input.fields["testInputField"].ast_node)
+            print_node(test_input.fields["testInputField"].ast_node)
             == "testInputField: TestEnum"
         )
 
         test_value = test_enum.values["TEST_VALUE"]
         assert test_value
-        assert print_ast(test_value.ast_node) == "TEST_VALUE"
+        assert print_node(test_value.ast_node) == "TEST_VALUE"
 
         assert (
-            print_ast(test_interface.fields["interfaceField"].ast_node)
+            print_node(test_interface.fields["interfaceField"].ast_node)
             == "interfaceField: String"
         )
         assert (
-            print_ast(test_type.fields["interfaceField"].ast_node)
+            print_node(test_type.fields["interfaceField"].ast_node)
             == "interfaceField: String"
         )
-        assert print_ast(test_directive.args["arg"].ast_node) == "arg: Int"
+        assert print_node(test_directive.args["arg"].ast_node) == "arg: Int"
 
     def builds_types_with_deprecated_fields_and_values():
         extended_schema = extend_test_schema(
@@ -1092,7 +1099,7 @@ def adds_schema_definition_missing_in_the_original_schema():
             schema = extend_schema(schema, parse(extension_sdl))
             query_type = schema.query_type
             assert query_type.name == "Foo"
-            assert print_ast(schema.ast_node) == extension_sdl.rstrip()
+            assert print_node(schema.ast_node) == extension_sdl.rstrip()
 
         def adds_new_root_types_via_schema_extension():
             schema = extend_test_schema(