[3.13] fix: remove ast.MatchStar.name class-level default value (gh-134674)

Lib/ast.py

@@ -155,8 +155,8 @@ def _format(node, level=0):
                     not show_empty
                     and (value is None or value == [])
                     # Special cases:
-                    # `Constant(value=None)` and `MatchSingleton(value=None)`
-                    and not isinstance(node, (Constant, MatchSingleton))
+                    # `Constant(value=None)` and `MatchSingleton(value=None)` and `MatchStar(name=None)`
+                    and not isinstance(node, (Constant, MatchSingleton, MatchStar))
                 ):
                     args_buffer.append(repr(value))
                     continue

Misc/NEWS.d/next/Library/2025-05-25-20-30-00.gh-issue-134674.MatchS.rst

@@ -0,0 +1,4 @@
+Fixed :class:`ast.MatchStar` to remove incorrect class-level default value
+for the ``name`` field.
+Fixed :func:`ast.dump` to show the ``name`` field of
+:class:`ast.MatchStar` when the value is ``None``.

Parser/Python.asdl

@@ -135,7 +135,7 @@ module Python
             | MatchMapping(expr* keys, pattern* patterns, identifier? rest)
             | MatchClass(expr cls, pattern* patterns, identifier* kwd_attrs, pattern* kwd_patterns)
 
-            | MatchStar(identifier? name)
+            | MatchStar(identifier name)
             -- The optional "rest" MatchMapping parameter handles capturing extra mapping keys
 
             | MatchAs(pattern? pattern, identifier? name)