[list] Add list.__delitem__ (#156339)

Pull Request resolved: https://github.com/pytorch/pytorch/pull/156339
Approved by: https://github.com/zou3519
ghstack dependencies: #153969, #156148, #156242, #156270, #156271

test/dynamo/test_list.py

@@ -2,7 +2,6 @@
 
 # TODO: move set tests from test_functions.py/test_misc.py to this file
 
-import unittest
 
 import torch
 import torch._dynamo.test_case
@@ -169,17 +168,6 @@ class TupleTests(torch._dynamo.test_case.TestCase):
         self.assertRaises(TypeError, p.__contains__)
         self.assertRaises(TypeError, p.__contains__, 1, 2)
 
-    @unittest.expectedFailure
-    @make_dynamo_test
-    def test___delitem__(self):
-        p = self.thetype("abc")
-        self.assertIsNone(p.__delitem__(1))
-        self.assertEqual(p, self.thetype("ac"))
-
-        # Wrong number of arguments
-        self.assertRaises(TypeError, p.__delitem__)
-        self.assertRaises(TypeError, p.__delitem__, 1, 2)
-
 
 class ListTests(TupleTests):
     # List methods
@@ -356,6 +344,20 @@ class ListTests(TupleTests):
         self.assertEqual(fn(x), x.sin())
         self.assertEqual(lst, ["a", "b"])
 
+    def test_binop_delitem_global_list(self):
+        global lst
+        lst = self.thetype(["a", "b", "c"])
+
+        @torch.compile(backend="eager", fullgraph=True)
+        def fn(x):
+            global lst
+            del lst[1]
+            return x.sin()
+
+        x = torch.tensor(1.0)
+        self.assertEqual(fn(x), x.sin())
+        self.assertEqual(lst, ["a", "c"])
+
     @make_dynamo_test
     def test___setitem__(self):
         p = self.thetype("abc")
@@ -370,6 +372,23 @@ class ListTests(TupleTests):
         self.assertRaises(TypeError, p.__setitem__, 1)
         self.assertRaises(TypeError, p.__setitem__, 1, 2, 3)
 
+    @make_dynamo_test
+    def test___delitem__(self):
+        p = self.thetype("abcdef")
+        self.assertIsNone(p.__delitem__(1))
+        self.assertEqual(p, self.thetype("acdef"))
+
+        self.assertIsNone(p.__delitem__(slice(1, 3)))
+        self.assertEqual(p, self.thetype("aef"))
+
+        # Slice step == 0
+        self.assertRaises(ValueError, p.__delitem__, slice(1, 1, 0))
+
+        # Wrong number of arguments
+        self.assertRaises(TypeError, p.__delitem__)
+        self.assertRaises(TypeError, p.__delitem__, 1.1)
+        self.assertRaises(TypeError, p.__delitem__, 1, 2)
+
 
 if __name__ == "__main__":
     from torch._dynamo.test_case import run_tests

torch/_dynamo/variables/lists.py

@@ -531,6 +531,33 @@ class CommonListMethodsVariable(BaseListVariable):
             else:
                 self.items[key.as_python_constant()] = value
             return ConstantVariable.create(None)
+        elif name == "__delitem__" and self.is_mutable():
+            if kwargs or len(args) != 1:
+                raise_args_mismatch(tx, name)
+
+            tx.output.side_effects.mutation(self)
+            if args[0].is_python_constant() and isinstance(
+                args[0].as_python_constant(), (int, slice)
+            ):
+                if isinstance(args[0], SymNodeVariable):
+                    idx = args[0].evaluate_expr()
+                else:
+                    idx = args[0].as_python_constant()
+
+                try:
+                    self.items.__delitem__(idx)
+                except (IndexError, ValueError) as exc:
+                    raise_observed_exception(
+                        type(exc),
+                        tx,
+                        args=list(map(ConstantVariable.create, exc.args)),
+                    )
+            else:
+                msg = ConstantVariable.create(
+                    f"list indices must be integers or slices, not {args[0].python_type_name()}"
+                )
+                raise_observed_exception(TypeError, tx, args=[msg])
+            return ConstantVariable.create(None)
         elif name == "copy":
             # List copy() doesn't have args and kwargs
             if args or kwargs: