Raise ValueError for None in Stmt lists to match CPython validator (RustPython#7670)

changjoon-park · web-flow · commit 0913563bbe08 · 2026-04-25T00:06:53.000+09:00
Sibling fix to RustPython#7656 (which handled Vec<Expr>). The same catch-all TypeError ("expected some sort of stmt, but got {}") in Stmt::ast_from_object silently swallowed None, so compile() on an AST with None in a statement-list field (ClassDef.body, Try.body, For.body, etc.) raised TypeError where CPython raises ValueError("None disallowed in statement list"). Add an is_none check before the catch-all, matching the Expr-side shape introduced in RustPython#7656. Option<Stmt> positions are unaffected — they short-circuit None earlier in node.rs. Unmasks test_classdef (body=[None] sub-case). Full test.test_ast.test_ast run: 227 tests, 0 unexpected successes, 38 expected failures (was 39).
diff --git a/Lib/test/test_ast/test_ast.py b/Lib/test/test_ast/test_ast.py
@@ -2108,7 +2108,6 @@ def foo(bar) -> pacarana:
         self.assertIsInstance(funcdef, ast.FunctionDef)
         self.assertTrue(matcher(funcdef))
 
-    @unittest.expectedFailure  # TODO: RUSTPYTHON; ValueError not raised
     def test_classdef(self):
         def cls(bases=None, keywords=None, body=None, decorator_list=None, type_params=None):
             if bases is None:
diff --git a/crates/vm/src/stdlib/_ast/statement.rs b/crates/vm/src/stdlib/_ast/statement.rs
@@ -135,6 +135,8 @@ impl Node for ast::Stmt {
                 source_file,
                 _object,
             )?)
+        } else if _vm.is_none(&_object) {
+            return Err(_vm.new_value_error("None disallowed in statement list"));
         } else {
             return Err(_vm.new_type_error(format!(
                 "expected some sort of stmt, but got {}",
