gh-118761: Optimise import time for ast (#131953)

.github/CODEOWNERS

@@ -188,6 +188,7 @@ Python/ast_opt.c              @isidentical @eclips4
 Parser/asdl.py                @isidentical @JelleZijlstra @eclips4
 Parser/asdl_c.py              @isidentical @JelleZijlstra @eclips4
 Lib/ast.py                    @isidentical @JelleZijlstra @eclips4
+Lib/_ast_unparse.py           @isidentical @JelleZijlstra @eclips4
 Lib/test/test_ast/            @eclips4
 
 # Mock

Lib/test/test_ast/test_ast.py

@@ -1,3 +1,4 @@
+import _ast_unparse
 import ast
 import builtins
 import copy
@@ -732,7 +733,7 @@ class AST_Tests(unittest.TestCase):
                     return self.__class__(self + 1)
                 except ValueError:
                     return self
-        enum._test_simple_enum(_Precedence, ast._Precedence)
+        enum._test_simple_enum(_Precedence, _ast_unparse._Precedence)
 
     @support.cpython_only
     @skip_wasi_stack_overflow()

Misc/NEWS.d/next/Library/2025-03-31-19-19-36.gh-issue-118761.M0yFiZ.rst

@@ -0,0 +1,2 @@
+Improve the import time of the :mod:`ast` module by extracting the
+:func:`~ast.unparse` function to a helper module.

Python/stdlib_module_names.h

@@ -8,6 +8,7 @@ static const char* _Py_stdlib_module_names[] = {
 "_android_support",
 "_apple_support",
 "_ast",
+"_ast_unparse",
 "_asyncio",
 "_bisect",
 "_blake2",