gh-126835: Disable tuple folding in the AST optimizer

Lib/test/test_ast/test_ast.py

@@ -3153,13 +3153,6 @@ def test_folding_binop(self):
             ):
                 self.assert_ast(result_code, non_optimized_target, optimized_target)
 
-        # Multiplication of constant tuples must be folded
-        code = "(1,) * 3"
-        non_optimized_target = self.wrap_expr(self.create_binop("*", ast.Tuple(elts=[ast.Constant(value=1)]), ast.Constant(value=3)))
-        optimized_target = self.wrap_expr(ast.Constant(eval(code)))
-
-        self.assert_ast(code, non_optimized_target, optimized_target)
-
     def test_folding_unaryop(self):
         code = "%s1"
         operators = self.unaryop.keys()
@@ -3179,38 +3172,6 @@ def create_unaryop(operand):
             ):
                 self.assert_ast(result_code, non_optimized_target, optimized_target)
 
-    def test_folding_not(self):
-        code = "not (1 %s (1,))"
-        operators = {
-            "in": ast.In(),
-            "is": ast.Is(),
-        }
-        opt_operators = {
-            "is": ast.IsNot(),
-            "in": ast.NotIn(),
-        }
-
-        def create_notop(operand):
-            return ast.UnaryOp(op=ast.Not(), operand=ast.Compare(
-                left=ast.Constant(value=1),
-                ops=[operators[operand]],
-                comparators=[ast.Tuple(elts=[ast.Constant(value=1)])]
-            ))
-
-        for op in operators.keys():
-            result_code = code % op
-            non_optimized_target = self.wrap_expr(create_notop(op))
-            optimized_target = self.wrap_expr(
-                ast.Compare(left=ast.Constant(1), ops=[opt_operators[op]], comparators=[ast.Constant(value=(1,))])
-            )
-
-            with self.subTest(
-                result_code=result_code,
-                non_optimized_target=non_optimized_target,
-                optimized_target=optimized_target
-            ):
-                self.assert_ast(result_code, non_optimized_target, optimized_target)
-
     def test_folding_format(self):
         code = "'%s' % (a,)"
 
@@ -3230,15 +3191,6 @@ def test_folding_format(self):
 
         self.assert_ast(code, non_optimized_target, optimized_target)
 
-
-    def test_folding_tuple(self):
-        code = "(1,)"
-
-        non_optimized_target = self.wrap_expr(ast.Tuple(elts=[ast.Constant(1)]))
-        optimized_target = self.wrap_expr(ast.Constant(value=(1,)))
-
-        self.assert_ast(code, non_optimized_target, optimized_target)
-
     def test_folding_comparator(self):
         code = "1 %s %s1%s"
         operators = [("in", ast.In()), ("not in", ast.NotIn())]
@@ -3280,13 +3232,14 @@ def test_folding_iter(self):
             self.assert_ast(code % (left, right), non_optimized_target, optimized_target)
 
     def test_folding_subscript(self):
-        code = "(1,)[0]"
+        code = "'abcd'[0]"
 
         non_optimized_target = self.wrap_expr(
-            ast.Subscript(value=ast.Tuple(elts=[ast.Constant(value=1)]), slice=ast.Constant(value=0))
+            ast.Subscript(value=ast.Constant(value='abcd'), slice=ast.Constant(value=0))
+        )
+        optimized_target = self.wrap_expr(
+            ast.JoinedStr(values=[ast.Constant(value='a')])
         )
-        optimized_target = self.wrap_expr(ast.Constant(value=1))
-
         self.assert_ast(code, non_optimized_target, optimized_target)
 
     def test_folding_type_param_in_function_def(self):

Lib/test/test_compile.py

@@ -793,14 +793,6 @@ def check_same_constant(const):
         self.check_constant(f1, Ellipsis)
         self.assertEqual(repr(f1()), repr(Ellipsis))
 
-        # Merge constants in tuple or frozenset
-        f1, f2 = lambda: "not a name", lambda: ("not a name",)
-        f3 = lambda x: x in {("not a name",)}
-        self.assertIs(f1.__code__.co_consts[0],
-                      f2.__code__.co_consts[0][0])
-        self.assertIs(next(iter(f3.__code__.co_consts[0])),
-                      f2.__code__.co_consts[0])
-
         # {0} is converted to a constant frozenset({0}) by the peephole
         # optimizer
         f1, f2 = lambda x: x in {0}, lambda x: x in {0}

Lib/test/test_opcache.py

@@ -1604,8 +1604,9 @@ def to_bool_str():
     @requires_specialization_ft
     def test_unpack_sequence(self):
         def unpack_sequence_two_tuple():
+            t = 1, 2
             for _ in range(100):
-                a, b = 1, 2
+                a, b = t
                 self.assertEqual(a, 1)
                 self.assertEqual(b, 2)
 
@@ -1616,8 +1617,8 @@ def unpack_sequence_two_tuple():
 
         def unpack_sequence_tuple():
             for _ in range(100):
-                a, = 1,
-                self.assertEqual(a, 1)
+                a, b, c, d = 1, 2, 3, 4
+                self.assertEqual((a, b, c, d), (1, 2, 3, 4))
 
         unpack_sequence_tuple()
         self.assert_specialized(unpack_sequence_tuple, "UNPACK_SEQUENCE_TUPLE")

Lib/test/test_peepholer.py

@@ -203,7 +203,8 @@ def test_folding_of_sets_of_constants(self):
             ('a in {1,2,3}', frozenset({1, 2, 3})),
             ('a not in {"a","b","c"}', frozenset({'a', 'c', 'b'})),
             ('a in {None, 1, None}', frozenset({1, None})),
-            ('a not in {(1, 2), 3, 4}', frozenset({(1, 2), 3, 4})),
+            # Tuple folding is currently disabled in the AST optimizer
+            # ('a not in {(1, 2), 3, 4}', frozenset({(1, 2), 3, 4})),
             ('a in {1, 2, 3, 3, 2, 1}', frozenset({1, 2, 3})),
             ):
             with self.subTest(line=line):
@@ -239,7 +240,8 @@ def test_folding_of_binops_on_constants(self):
             ('a = 14%4', 2),                    # binary modulo
             ('a = 2+3', 5),                     # binary add
             ('a = 13-4', 9),                    # binary subtract
-            ('a = (12,13)[1]', 13),             # binary subscr
+            # Tuple folding is currently disabled in the AST optimizer
+            # ('a = (12,13)[1]', 13),             # binary subscr
             ('a = 13 << 2', 52),                # binary lshift
             ('a = 13 >> 2', 3),                 # binary rshift
             ('a = 13 & 7', 5),                  # binary and
@@ -457,12 +459,13 @@ def test_constant_folding(self):
             '3 * -5',
             '-3 * 5',
             '2 * (3 * 4)',
-            '(2 * 3) * 4',
-            '(-1, 2, 3)',
-            '(1, -2, 3)',
-            '(1, 2, -3)',
-            '(1, 2, -3) * 6',
-            'lambda x: x in {(3 * -5) + (-1 - 6), (1, -2, 3) * 2, None}',
+            # Tuple folding is currently disabled in the AST optimizer
+            # '(2 * 3) * 4',
+            # '(-1, 2, 3)',
+            # '(1, -2, 3)',
+            # '(1, 2, -3)',
+            # '(1, 2, -3) * 6',
+            # 'lambda x: x in {(3 * -5) + (-1 - 6), (1, -2, 3) * 2, None}',
         ]
         for e in exprs:
             with self.subTest(e=e):

Python/ast_opt.c

@@ -555,18 +555,6 @@ make_const_tuple(asdl_expr_seq *elts)
     return newval;
 }
 
-static int
-fold_tuple(expr_ty node, PyArena *arena, _PyASTOptimizeState *state)
-{
-    PyObject *newval;
-
-    if (node->v.Tuple.ctx != Load)
-        return 1;
-
-    newval = make_const_tuple(node->v.Tuple.elts);
-    return make_const(node, newval, arena);
-}
-
 static int
 fold_subscr(expr_ty node, PyArena *arena, _PyASTOptimizeState *state)
 {
@@ -837,7 +825,6 @@ astfold_expr(expr_ty node_, PyArena *ctx_, _PyASTOptimizeState *state)
         break;
     case Tuple_kind:
         CALL_SEQ(astfold_expr, expr, node_->v.Tuple.elts);
-        CALL(fold_tuple, expr_ty, node_);
         break;
     case Name_kind:
         if (node_->v.Name.ctx == Load &&

Python/codegen.c

@@ -1696,11 +1696,26 @@ codegen_typealias(compiler *c, stmt_ty s)
     return SUCCESS;
 }
 
+static bool
+is_const_tuple(asdl_expr_seq *elts)
+{
+    for (Py_ssize_t i = 0; i < asdl_seq_LEN(elts); i++) {
+        expr_ty e = (expr_ty)asdl_seq_GET(elts, i);
+        if (e->kind != Constant_kind) {
+            return false;
+        }
+    }
+    return true;
+}
+
 /* Return false if the expression is a constant value except named singletons.
    Return true otherwise. */
 static bool
 check_is_arg(expr_ty e)
 {
+    if (e->kind == Tuple_kind) {
+        return !is_const_tuple(e->v.Tuple.elts);
+    }
     if (e->kind != Constant_kind) {
         return true;
     }