Add support for directives on directive definitions

Replicates graphql/graphql-js@ad9c519

Author: Cito

docs/modules/language.rst

@@ -25,6 +25,7 @@ Each kind of AST node has its own class:
 .. autoclass:: ConstValueNode
 .. autoclass:: DefinitionNode
 .. autoclass:: DirectiveDefinitionNode
+.. autoclass:: DirectiveExtensionNode
 .. autoclass:: DirectiveNode
 .. autoclass:: DocumentNode
 .. autoclass:: EnumTypeDefinitionNode

src/graphql/__init__.py

@@ -160,6 +160,7 @@
     UnionTypeExtensionNode,
     EnumTypeExtensionNode,
     InputObjectTypeExtensionNode,
+    DirectiveExtensionNode,
     # Schema Coordinates
     SchemaCoordinateNode,
     TypeCoordinateNode,
@@ -709,6 +710,7 @@
     "UnionTypeExtensionNode",
     "EnumTypeExtensionNode",
     "InputObjectTypeExtensionNode",
+    "DirectiveExtensionNode",
     "SchemaCoordinateNode",
     "TypeCoordinateNode",
     "MemberCoordinateNode",

src/graphql/execution/values.py

@@ -2,6 +2,8 @@
 
 from ..error import GraphQLError
 from ..language import (
+    DirectiveDefinitionNode,
+    DirectiveExtensionNode,
     DirectiveNode,
     EnumValueDefinitionNode,
     ExecutableDefinitionNode,
@@ -224,6 +226,8 @@ def get_argument_values(
 
 
 NodeWithDirective = Union[
+    DirectiveDefinitionNode,
+    DirectiveExtensionNode,
     EnumValueDefinitionNode,
     ExecutableDefinitionNode,
     FieldDefinitionNode,

src/graphql/language/__init__.py

@@ -100,6 +100,7 @@
     UnionTypeExtensionNode,
     EnumTypeExtensionNode,
     InputObjectTypeExtensionNode,
+    DirectiveExtensionNode,
     SchemaCoordinateNode,
     TypeCoordinateNode,
     MemberCoordinateNode,
@@ -209,6 +210,7 @@
     "UnionTypeExtensionNode",
     "EnumTypeExtensionNode",
     "InputObjectTypeExtensionNode",
+    "DirectiveExtensionNode",
     "SchemaCoordinateNode",
     "TypeCoordinateNode",
     "MemberCoordinateNode",

src/graphql/language/ast.py

@@ -69,6 +69,7 @@
     "UnionTypeExtensionNode",
     "EnumTypeExtensionNode",
     "InputObjectTypeExtensionNode",
+    "DirectiveExtensionNode",
     "SchemaCoordinateNode",
     "TypeCoordinateNode",
     "MemberCoordinateNode",
@@ -312,8 +313,15 @@ class OperationType(Enum):
     "enum_type_definition": ("description", "name", "directives", "values"),
     "enum_value_definition": ("description", "name", "directives"),
     "input_object_type_definition": ("description", "name", "directives", "fields"),
-    "directive_definition": ("description", "name", "arguments", "locations"),
+    "directive_definition": (
+        "description",
+        "name",
+        "arguments",
+        "directives",
+        "locations",
+    ),
     "schema_extension": ("directives", "operation_types"),
+    "directive_extension": ("name", "directives"),
     "scalar_type_extension": ("name", "directives"),
     "object_type_extension": ("name", "interfaces", "directives", "fields"),
     "interface_type_extension": ("name", "interfaces", "directives", "fields"),
@@ -771,11 +779,19 @@ class InputObjectTypeDefinitionNode(TypeDefinitionNode):
 
 
 class DirectiveDefinitionNode(TypeSystemDefinitionNode):
-    __slots__ = "description", "name", "arguments", "repeatable", "locations"
+    __slots__ = (
+        "description",
+        "name",
+        "arguments",
+        "directives",
+        "repeatable",
+        "locations",
+    )
 
     description: Optional[StringValueNode]
     name: NameNode
     arguments: Tuple[InputValueDefinitionNode, ...]
+    directives: Tuple[ConstDirectiveNode, ...]
     repeatable: bool
     locations: Tuple[NameNode, ...]
 
@@ -790,6 +806,13 @@ class SchemaExtensionNode(Node):
     operation_types: Tuple[OperationTypeDefinitionNode, ...]
 
 
+class DirectiveExtensionNode(Node):
+    __slots__ = "name", "directives"
+
+    name: NameNode
+    directives: Tuple[ConstDirectiveNode, ...]
+
+
 # Type Extensions
 
 
@@ -800,7 +823,9 @@ class TypeExtensionNode(TypeSystemDefinitionNode):
     directives: Tuple[ConstDirectiveNode, ...]
 
 
-TypeSystemExtensionNode = Union[SchemaExtensionNode, TypeExtensionNode]
+TypeSystemExtensionNode = Union[
+    SchemaExtensionNode, TypeExtensionNode, DirectiveExtensionNode
+]
 
 
 class ScalarTypeExtensionNode(TypeExtensionNode):

src/graphql/language/directive_locations.py

@@ -28,3 +28,4 @@ class DirectiveLocation(Enum):
     ENUM_VALUE = "enum value"
     INPUT_OBJECT = "input object"
     INPUT_FIELD_DEFINITION = "input field definition"
+    DIRECTIVE_DEFINITION = "directive definition"

src/graphql/language/parser.py

@@ -13,6 +13,7 @@
     DirectiveArgumentCoordinateNode,
     DirectiveCoordinateNode,
     DirectiveDefinitionNode,
+    DirectiveExtensionNode,
     DirectiveNode,
     DocumentNode,
     EnumTypeDefinitionNode,
@@ -88,6 +89,7 @@ def parse(
     no_location: bool = False,
     max_tokens: Optional[int] = None,
     allow_legacy_fragment_variables: bool = False,
+    experimental_directives_on_directive_definitions: bool = False,
 ) -> DocumentNode:
     """Given a GraphQL source, parse it into a Document.
 
@@ -116,12 +118,23 @@ def parse(
         fragment A($var: Boolean = false) on T  {
           ...
         }
+
+    Experimental feature:
+
+    If ``experimental_directives_on_directive_definitions`` is set to ``True``, the
+    parser will understand and parse directives on directive definitions. This syntax
+    is not part of the GraphQL specification and may change. For example::
+
+        directive @foo @bar on FIELD
     """
     parser = Parser(
         source,
         no_location=no_location,
         max_tokens=max_tokens,
         allow_legacy_fragment_variables=allow_legacy_fragment_variables,
+        experimental_directives_on_directive_definitions=(
+            experimental_directives_on_directive_definitions
+        ),
     )
     return parser.parse_document()
 
@@ -131,6 +144,7 @@ def parse_value(
     no_location: bool = False,
     max_tokens: Optional[int] = None,
     allow_legacy_fragment_variables: bool = False,
+    experimental_directives_on_directive_definitions: bool = False,
 ) -> ValueNode:
     """Parse the AST for a given string containing a GraphQL value.
 
@@ -147,6 +161,9 @@ def parse_value(
         no_location=no_location,
         max_tokens=max_tokens,
         allow_legacy_fragment_variables=allow_legacy_fragment_variables,
+        experimental_directives_on_directive_definitions=(
+            experimental_directives_on_directive_definitions
+        ),
     )
     parser.expect_token(TokenKind.SOF)
     value = parser.parse_value_literal(False)
@@ -159,6 +176,7 @@ def parse_const_value(
     no_location: bool = False,
     max_tokens: Optional[int] = None,
     allow_legacy_fragment_variables: bool = False,
+    experimental_directives_on_directive_definitions: bool = False,
 ) -> ConstValueNode:
     """Parse the AST for a given string containing a GraphQL constant value.
 
@@ -170,6 +188,9 @@ def parse_const_value(
         no_location=no_location,
         max_tokens=max_tokens,
         allow_legacy_fragment_variables=allow_legacy_fragment_variables,
+        experimental_directives_on_directive_definitions=(
+            experimental_directives_on_directive_definitions
+        ),
     )
     parser.expect_token(TokenKind.SOF)
     value = parser.parse_const_value_literal()
@@ -182,6 +203,7 @@ def parse_type(
     no_location: bool = False,
     max_tokens: Optional[int] = None,
     allow_legacy_fragment_variables: bool = False,
+    experimental_directives_on_directive_definitions: bool = False,
 ) -> TypeNode:
     """Parse the AST for a given string containing a GraphQL Type.
 
@@ -198,6 +220,9 @@ def parse_type(
         no_location=no_location,
         max_tokens=max_tokens,
         allow_legacy_fragment_variables=allow_legacy_fragment_variables,
+        experimental_directives_on_directive_definitions=(
+            experimental_directives_on_directive_definitions
+        ),
     )
     parser.expect_token(TokenKind.SOF)
     type_ = parser.parse_type_reference()
@@ -247,6 +272,7 @@ class Parser:
     _no_location: bool
     _max_tokens: Optional[int]
     _allow_legacy_fragment_variables: bool
+    _experimental_directives_on_directive_definitions: bool
     _token_counter: int
 
     def __init__(
@@ -255,6 +281,7 @@ def __init__(
         no_location: bool = False,
         max_tokens: Optional[int] = None,
         allow_legacy_fragment_variables: bool = False,
+        experimental_directives_on_directive_definitions: bool = False,
         lexer: Optional[Lexer] = None,
     ):
         source = (
@@ -267,6 +294,9 @@ def __init__(
         self._no_location = no_location
         self._max_tokens = max_tokens
         self._allow_legacy_fragment_variables = allow_legacy_fragment_variables
+        self._experimental_directives_on_directive_definitions = (
+            experimental_directives_on_directive_definitions
+        )
         self._token_counter = 0
 
     def parse_name(self) -> NameNode:
@@ -710,6 +740,11 @@ def parse_type_system_extension(self) -> TypeSystemExtensionNode:
             )
             if method_name:  # pragma: no cover
                 return getattr(self, f"parse_{method_name}")()
+            if (
+                keyword_token.value == "directive"
+                and self._experimental_directives_on_directive_definitions
+            ):
+                return self.parse_directive_definition_extension()
         raise self.unexpected(keyword_token)
 
     def peek_description(self) -> bool:
@@ -1057,6 +1092,22 @@ def parse_input_object_type_extension(self) -> InputObjectTypeExtensionNode:
             name=name, directives=directives, fields=fields, loc=self.loc(start)
         )
 
+    def parse_directive_definition_extension(self) -> DirectiveExtensionNode:
+        """DirectiveDefinitionExtension"""
+        start = self._lexer.token
+        self.expect_keyword("extend")
+        self.expect_keyword("directive")
+        self.expect_token(TokenKind.AT)
+        name = self.parse_name()
+        directives = self.parse_const_directives()
+        if not directives:
+            raise self.unexpected()
+        return DirectiveExtensionNode(
+            name=name,
+            directives=directives,
+            loc=self.loc(start),
+        )
+
     def parse_directive_definition(self) -> DirectiveDefinitionNode:
         """DirectiveDefinition"""
         start = self._lexer.token
@@ -1065,13 +1116,19 @@ def parse_directive_definition(self) -> DirectiveDefinitionNode:
         self.expect_token(TokenKind.AT)
         name = self.parse_name()
         args = self.parse_argument_defs()
+        directives = (
+            self.parse_const_directives()
+            if self._experimental_directives_on_directive_definitions
+            else []
+        )
         repeatable = self.expect_optional_keyword("repeatable")
         self.expect_keyword("on")
         locations = self.parse_directive_locations()
         return DirectiveDefinitionNode(
             description=description,
             name=name,
             arguments=args,
+            directives=directives,
             repeatable=repeatable,
             locations=locations,
             loc=self.loc(start),

src/graphql/language/predicates.py

@@ -5,6 +5,7 @@
     MemberCoordinateNode,
     Node,
     DefinitionNode,
+    DirectiveExtensionNode,
     ExecutableDefinitionNode,
     ListValueNode,
     ObjectValueNode,
@@ -84,7 +85,9 @@ def is_type_definition_node(node: Node) -> bool:
 
 def is_type_system_extension_node(node: Node) -> bool:
     """Check whether the given node represents a type system extension."""
-    return isinstance(node, (SchemaExtensionNode, TypeExtensionNode))
+    return isinstance(
+        node, (SchemaExtensionNode, DirectiveExtensionNode, TypeExtensionNode)
+    )
 
 
 def is_type_extension_node(node: Node) -> bool:

src/graphql/language/printer.py

@@ -318,11 +318,12 @@ def leave_directive_definition(node: PrintedNode, *_args: Any) -> str:
             if has_multiline_items(args)
             else wrap("(", join(args, ", "), ")")
         )
+        directives = wrap(" ", join(node.directives, " "))
         repeatable = " repeatable" if node.repeatable else ""
         locations = join(node.locations, " | ")
         return (
             wrap("", node.description, "\n")
-            + f"directive @{node.name}{args}{repeatable} on {locations}"
+            + f"directive @{node.name}{args}{directives}{repeatable} on {locations}"
         )
 
     @staticmethod
@@ -332,6 +333,10 @@ def leave_schema_extension(node: PrintedNode, *_args: Any) -> str:
             " ",
         )
 
+    @staticmethod
+    def leave_directive_extension(node: PrintedNode, *_args: Any) -> str:
+        return join((f"extend directive @{node.name}", join(node.directives, " ")), " ")
+
     @staticmethod
     def leave_scalar_type_extension(node: PrintedNode, *_args: Any) -> str:
         return join(("extend scalar", node.name, join(node.directives, " ")), " ")