From 3a0c27b74cd77b3af1bf4606e1ba45f8589e6563 Mon Sep 17 00:00:00 2001
From: Sigmund Cherem <sigmund@google.com>
Date: Tue, 11 May 2021 22:14:28 +0000
Subject: [PATCH] [ddc] Add a regression test for issue #45874

Expandos collide after a hot restart. This currently fails because
the DDC implementation uses a static field (_keyCounter) to compute a
unique name for each expando. After a hot-restart the counter gets reset
and keys get reused accidentally.

A hacky fix would be to ensure this field is not reset after restarts,
but a more robust fix would be to use a weak map implementation like
dart2js does.

Change-Id: I991874aabf836be66cbd44de07dd38e681415ae7
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/199221
Reviewed-by: Nicholas Shahan <nshahan@google.com>
---
 tests/dartdevc/hot_restart_expando_test.dart  | 30 +++++++++++++++++++
 .../dartdevc_2/hot_restart_expando_test.dart  | 30 +++++++++++++++++++
 2 files changed, 60 insertions(+)
 create mode 100644 tests/dartdevc/hot_restart_expando_test.dart
 create mode 100644 tests/dartdevc_2/hot_restart_expando_test.dart

diff --git a/tests/dartdevc/hot_restart_expando_test.dart b/tests/dartdevc/hot_restart_expando_test.dart
new file mode 100644
index 00000000000..4802a52423f
--- /dev/null
+++ b/tests/dartdevc/hot_restart_expando_test.dart
@@ -0,0 +1,30 @@
+// Copyright (c) 2019, the Dart project authors.  Please see the AUTHORS file
+// for details. All rights reserved. Use of this source code is governed by a
+// BSD-style license that can be found in the LICENSE file.
+
+import 'dart:_runtime' as dart;
+
+import 'package:expect/expect.dart';
+import 'package:js/js.dart';
+
+final e = Expando<int>();
+
+@JS()
+external void eval(String s);
+
+@JS()
+external Object get singleton;
+
+void main() {
+  eval('''
+    if (!self.singleton) {
+      self.singleton = {};
+    }
+  ''');
+  var o = singleton;
+  Expect.equals(null, e[o]);
+  e[o] = 1;
+
+  dart.hotRestart();
+  Expect.equals(null, e[o]);
+}
diff --git a/tests/dartdevc_2/hot_restart_expando_test.dart b/tests/dartdevc_2/hot_restart_expando_test.dart
new file mode 100644
index 00000000000..4802a52423f
--- /dev/null
+++ b/tests/dartdevc_2/hot_restart_expando_test.dart
@@ -0,0 +1,30 @@
+// Copyright (c) 2019, the Dart project authors.  Please see the AUTHORS file
+// for details. All rights reserved. Use of this source code is governed by a
+// BSD-style license that can be found in the LICENSE file.
+
+import 'dart:_runtime' as dart;
+
+import 'package:expect/expect.dart';
+import 'package:js/js.dart';
+
+final e = Expando<int>();
+
+@JS()
+external void eval(String s);
+
+@JS()
+external Object get singleton;
+
+void main() {
+  eval('''
+    if (!self.singleton) {
+      self.singleton = {};
+    }
+  ''');
+  var o = singleton;
+  Expect.equals(null, e[o]);
+  e[o] = 1;
+
+  dart.hotRestart();
+  Expect.equals(null, e[o]);
+}