Incorrect validation errors when variable descriptions are used

Replicates graphql/graphql-js@3f8f27a3

Author: Cito

src/graphql/validation/rules/values_of_correct_type.py

@@ -120,6 +120,11 @@ def enter_int_value(self, node: IntValueNode, *_args: Any) -> None:
     def enter_float_value(self, node: FloatValueNode, *_args: Any) -> None:
         self.is_valid_value_node(node)
 
+    # Descriptions are string values that would not validate according
+    # to the below logic, but since (per the specification) descriptions must
+    # not affect validation, they are ignored entirely when visiting the AST
+    # and do not require special handling.
+    # See https://spec.graphql.org/draft/#sec-Descriptions
     def enter_string_value(self, node: StringValueNode, *_args: Any) -> None:
         self.is_valid_value_node(node)
 

src/graphql/validation/validate.py

@@ -1,7 +1,8 @@
-from typing import Collection, List, Optional, Type
+from typing import Collection, Dict, List, Optional, Tuple, Type
 
 from ..error import GraphQLError
 from ..language import DocumentNode, ParallelVisitor, visit
+from ..language.ast import QUERY_DOCUMENT_KEYS
 from ..pyutils import inspect, is_collection
 from ..type import GraphQLSchema, assert_valid_schema
 from ..utilities import TypeInfo, TypeInfoVisitor
@@ -16,6 +17,14 @@ class ValidationAbortedError(RuntimeError):
     """Error when a validation has been aborted (error limit reached)."""
 
 
+# Per the specification, descriptions must not affect validation.
+# See https://spec.graphql.org/draft/#sec-Descriptions
+query_document_keys_to_validate: Dict[str, Tuple[str, ...]] = {
+    kind: tuple(key for key in keys if key != "description")
+    for kind, keys in QUERY_DOCUMENT_KEYS.items()
+}
+
+
 def validate(
     schema: GraphQLSchema,
     document_ast: DocumentNode,
@@ -83,7 +92,11 @@ def on_error(error: GraphQLError) -> None:
 
     # Visit the whole document with each instance of all provided rules.
     try:
-        visit(document_ast, TypeInfoVisitor(type_info, ParallelVisitor(visitors)))
+        visit(
+            document_ast,
+            TypeInfoVisitor(type_info, ParallelVisitor(visitors)),
+            query_document_keys_to_validate,
+        )
     except ValidationAbortedError:
         pass
     return errors

tests/validation/test_validation.py

@@ -192,3 +192,22 @@ def enter_field(self, *_args):
 
         with raises(RuntimeError, match="^Error from custom rule!$"):
             validate(test_schema, doc, [CustomRule], max_errors=1)
+
+
+def describe_operation_and_variable_definition_descriptions():
+    def validates_operation_with_description_and_variable_descriptions():
+        schema = build_schema("type Query { field(a: Int, b: String): String }")
+        query = '''
+            "Operation description"
+            query myQuery(
+              "Variable a description"
+              $a: Int,
+              """Variable b\nmultiline description"""
+              $b: String
+            ) {
+              field(a: $a, b: $b)
+            }
+            '''
+        ast = parse(query)
+        errors = validate(schema, ast)
+        assert errors == []