Allow empty string as valid 'deprecation_reason'

Replicates graphql/graphql-js@43b7645

Author: Cito

README.md

@@ -16,7 +16,7 @@ The current stable version 3.0.1 of GraphQL-core is up-to-date
 with GraphQL.js version 14.5.8.
 
 All parts of the API are covered by an extensive test suite
-of currently 1991 unit tests.
+of currently 1992 unit tests.
 
 
 ## Documentation

src/graphql/type/definition.py

@@ -527,7 +527,7 @@ def to_kwargs(self) -> Dict[str, Any]:
 
     @property
     def is_deprecated(self) -> bool:
-        return bool(self.deprecation_reason)
+        return self.deprecation_reason is not None
 
 
 class GraphQLResolveInfo(NamedTuple):
@@ -1177,7 +1177,7 @@ def to_kwargs(self) -> Dict[str, Any]:
 
     @property
     def is_deprecated(self) -> bool:
-        return bool(self.deprecation_reason)
+        return self.deprecation_reason is not None
 
 
 GraphQLInputFieldMap = Dict[str, "GraphQLInputField"]

src/graphql/utilities/schema_printer.py

@@ -250,7 +250,7 @@ def print_deprecated(field_or_enum_value: Union[GraphQLField, GraphQLEnumValue])
         return ""
     reason = field_or_enum_value.deprecation_reason
     reason_ast = ast_from_value(reason, GraphQLString)
-    if not reason_ast or reason == "" or reason == DEFAULT_DEPRECATION_REASON:
+    if not reason_ast or reason == DEFAULT_DEPRECATION_REASON:
         return " @deprecated"
     return f" @deprecated(reason: {print_ast(reason_ast)})"
 

tests/type/test_definition.py

@@ -330,22 +330,23 @@ def does_not_mutate_passed_field_definitions():
     def defines_an_object_type_with_deprecated_field():
         TypeWithDeprecatedField = GraphQLObjectType(
             "foo",
-            {"bar": GraphQLField(ScalarType, deprecation_reason="A terrible reason")},
+            {
+                "bar": GraphQLField(ScalarType, deprecation_reason="A terrible reason"),
+                "baz": GraphQLField(ScalarType, deprecation_reason=""),
+            },
         )
 
         deprecated_field = TypeWithDeprecatedField.fields["bar"]
         assert deprecated_field == GraphQLField(
             ScalarType, deprecation_reason="A terrible reason"
         )
-        assert deprecated_field.description is None
-        assert deprecated_field.type is ScalarType
-        assert deprecated_field.args == {}
-        assert deprecated_field.resolve is None
-        assert deprecated_field.subscribe is None
         assert deprecated_field.is_deprecated is True
         assert deprecated_field.deprecation_reason == "A terrible reason"
-        assert deprecated_field.extensions is None
-        assert deprecated_field.ast_node is None
+
+        deprecated_field = TypeWithDeprecatedField.fields["baz"]
+        assert deprecated_field == GraphQLField(ScalarType, deprecation_reason="")
+        assert deprecated_field.is_deprecated is True
+        assert deprecated_field.deprecation_reason == ""
 
     def accepts_an_object_type_with_output_type_as_field():
         # this is a shortcut syntax for simple fields

tests/utilities/test_build_client_schema.py

@@ -478,6 +478,21 @@ def builds_a_schema_aware_of_deprecation():
 
         assert cycle_introspection(sdl) == sdl
 
+    def builds_a_schema_with_empty_deprecation_reasons():
+        sdl = dedent(
+            """
+            type Query {
+              someField: String @deprecated(reason: "")
+            }
+
+            enum SomeEnum {
+              SOME_VALUE @deprecated(reason: "")
+            }
+            """
+        )
+
+        assert cycle_introspection(sdl) == sdl
+
     def can_use_client_schema_for_limited_execution():
         schema = build_schema(
             """