msg="source code string cannot contain null bytes"):

ast.parse("a\0b")

defassert_none_check(self,node:type[ast.AST],attr:str,source:str)->None:

withself.subTest(f"{node.__name__}.{attr}"):

tree=ast.parse(source)

forchildinast.walk(tree):

ifisinstance(child,node):

setattr(child,attr,None)

self.assertEqual(found,1)

e=re.escape(f"field '{attr}' is required for{node.__name__}")

withself.assertRaisesRegex(ValueError,f"^{e}$"):

compile(tree,"<test>","exec")

deftest_none_checks(self)->None:

tests= [

(ast.alias,"name","import spam as SPAM"),

(ast.arg,"arg","def spam(SPAM): spam"),

(ast.comprehension,"target","[spam for SPAM in spam]"),

(ast.comprehension,"iter","[spam for spam in SPAM]"),

(ast.keyword,"value","spam(**SPAM)"),

(ast.match_case,"pattern","match spam:\n case SPAM: spam"),

(ast.withitem,"context_expr","with SPAM: spam"),

]

fornode,attr,sourceintests:

self.assert_none_check(node,attr,source)

classASTHelpers_Test(unittest.TestCase):

Fix an issue that could result in crashes when compiling malformed

:mod:`ast` nodes.

args= [f.nameforfinprod.fields]

args.extend([a.nameforainprod.attributes])

self.emit("*out = %s(%s);"% (ast_func_name(name),self.buildArgs(args)),1)

self.emit("if (*out == NULL) goto failed;",1)

self.emit("return 0;",1)

self.emit("failed:",0)

self.emit("Py_XDECREF(tmp);",1)