[dart2js] Handle Object members of dart:html types

`dart:html` types have changed to inherit `JavaScriptObject`. Therefore,
the dart2js runtime needs to be changed so that interceptors are still
created for those types, and they're properly handled in `toString`
calculations. Includes tests on `Object` members that are currently
inconsistent between both compilers.

This test passes on dart2js with and without making the types in `dart:html`
extend `JavaScriptObject`. This test fails in DDC for the following reasons:

- `toString` of native types calls the native `toString`
- `hashCode` for interop objects are random and not 0
- `runtimeType` of interop objects is `LegacyJavaScriptObject` not `JSObject`

Change-Id: Ibf80109174615120df9e64995fa13016f7a1677b
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/228741
Reviewed-by: Stephen Adams <sra@google.com>
Commit-Queue: Srujan Gaddam <srujzs@google.com>

pkg/compiler/lib/src/js_emitter/native_emitter.dart

@@ -94,6 +94,7 @@ class NativeEmitter {
 
     Class objectClass = null;
     Class jsInterceptorClass = null;
+    Class jsJavaScriptObjectClass = null;
 
     void walk(Class cls) {
       if (cls.element == _commonElements.objectClass) {
@@ -104,6 +105,11 @@ class NativeEmitter {
         jsInterceptorClass = cls;
         return;
       }
+      // Native classes may inherit either `Interceptor` e.g. `JSBool` or
+      // `JavaScriptObject` e.g. `dart:html` classes.
+      if (cls.element == _commonElements.jsJavaScriptObjectClass) {
+        jsJavaScriptObjectClass = cls;
+      }
       if (seen.contains(cls)) return;
       seen.add(cls);
       walk(cls.superclass);
@@ -215,6 +221,9 @@ class NativeEmitter {
     // by getNativeInterceptor and custom elements.
     if (_nativeCodegenEnqueuer.hasInstantiatedNativeClasses) {
       fillNativeInfo(jsInterceptorClass);
+      if (jsJavaScriptObjectClass != null) {
+        fillNativeInfo(jsJavaScriptObjectClass);
+      }
       for (Class cls in classes) {
         if (!cls.isNative || neededClasses.contains(cls)) {
           fillNativeInfo(cls);

pkg/compiler/test/jsinterop/internal_annotations_test.dart

@@ -184,7 +184,15 @@ $mainSource
             "Expected $name to be indirectly instantiated in `${mainSource}`:"
             "\n${world.classHierarchy.dump(cls)}");
       }
-      if (!isInstantiated && (name != 'Object' && name != 'Interceptor')) {
+      // Classes that are expected to be instantiated by default. `Object` and
+      // `Interceptor` are base types for non-native and native types, and
+      // `JavaScriptObject` is the base type for `dart:html` types.
+      var insantiatedBaseClasses = [
+        'Object',
+        'Interceptor',
+        'JavaScriptObject'
+      ];
+      if (!isInstantiated && !insantiatedBaseClasses.contains(name)) {
         Expect.isFalse(
             world.classHierarchy.isInstantiated(cls),
             "Expected $name to be uninstantiated in `${mainSource}`:"

pkg/compiler/test/jsinterop/world_test.dart

@@ -178,7 +178,15 @@ $mainSource
             "Expected $name to be indirectly instantiated in `${mainSource}`:"
             "\n${world.classHierarchy.dump(cls)}");
       }
-      if (!isInstantiated && (name != 'Object' && name != 'Interceptor')) {
+      // Classes that are expected to be instantiated by default. `Object` and
+      // `Interceptor` are base types for non-native and native types, and
+      // `JavaScriptObject` is the base type for `dart:html` types.
+      var insantiatedBaseClasses = [
+        'Object',
+        'Interceptor',
+        'JavaScriptObject'
+      ];
+      if (!isInstantiated && !insantiatedBaseClasses.contains(name)) {
         Expect.isFalse(
             world.classHierarchy.isInstantiated(cls),
             "Expected $name to be uninstantiated in `${mainSource}`:"

sdk/lib/_internal/js_runtime/lib/js_helper.dart

@@ -415,19 +415,21 @@ class Primitives {
 
     var interceptor = getInterceptor(object);
     if (identical(interceptor, JS_INTERCEPTOR_CONSTANT(Interceptor)) ||
+        identical(interceptor, JS_INTERCEPTOR_CONSTANT(JavaScriptObject)) ||
         object is UnknownJavaScriptObject) {
       // Try to do better.  If we do not find something better, fallthrough to
-      // Dart-type based name that leave the name as 'UnknownJavaScriptObject'
-      // or 'Interceptor' (or the minified versions thereof).
+      // Dart-type based name that leave the name as 'UnknownJavaScriptObject',
+      // 'Interceptor', or 'JavaScriptObject' (or their minified versions).
       //
       // When we get here via the UnknownJavaScriptObject test (for JavaScript
       // objects from outside the program), the object's constructor has a
       // better name that 'UnknownJavaScriptObject'.
       //
-      // When we get here the Interceptor test (for Native classes that are
-      // declared in the Dart program but have been 'folded' into Interceptor),
-      // the native class's constructor name is better than the generic
-      // 'Interceptor' (an abstract class).
+      // When we get here via either the Interceptor or JavaScriptObject test
+      // (for Native classes that are declared in the Dart program but have been
+      // 'folded' into one of those interceptors), the native class's
+      // constructor name is better than the generic 'Interceptor' or
+      // 'JavaScriptObject'.
 
       // Try the [constructorNameFallback]. This gets the constructor name for
       // any browser (used by [getNativeInterceptor]).

tests/web/internal/object_members_test.dart

@@ -0,0 +1,80 @@
+// Copyright (c) 2022, 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.
+
+// Make sure `Object` methods work as expected with `dart:html` and interop
+// types. The expectations here aren't guarantees that they should work a
+// particular way, but rather a way to monitor regressions/changes.
+
+@JS()
+library object_members_test;
+
+import 'package:js/js.dart';
+import 'package:expect/minitest.dart';
+
+import 'dart:html';
+import 'dart:_interceptors' show JSObject;
+
+@JS()
+external void eval(String code);
+
+@JS()
+class JSClass {
+  external JSClass();
+}
+
+void main() {
+  eval(r'''
+    function JSClass() {}
+  ''');
+
+  // `dart:html` type.
+  var div = document.createElement('div');
+  expect(div == div, true);
+  expect(div == DomPointReadOnly(), false);
+  // Ensure that we get a random hash for each new instance. It should be
+  // improbable for this to fail across many runs if the hash is
+  // non-deterministic.
+  var hashCode = div.hashCode;
+  var attempts = 0;
+  var maxAttempts = 1000;
+  while (div.hashCode == hashCode && attempts < maxAttempts) {
+    div = document.createElement('div');
+    attempts++;
+  }
+  expect(attempts > 0 && attempts != maxAttempts, isTrue);
+  expect(div.toString, isNotNull);
+  expect(div.toString(), 'div');
+  expect(div.noSuchMethod, isNotNull);
+  var noSuchMethodErrorThrown = true;
+  try {
+    (div as dynamic).triggerNoSuchMethod();
+    noSuchMethodErrorThrown = false;
+  } catch (_) {}
+  expect(noSuchMethodErrorThrown, isTrue);
+  expect(div.runtimeType, DivElement);
+
+  // `toString` for `dart:html` types that do not have an overridden `toString`
+  // should look up the type through the proto.
+  expect(window.navigator.toString(), "Instance of 'Navigator'");
+
+  // Interop type.
+  var js = JSClass();
+  expect(js == js, true);
+  expect(js == JSClass(), false);
+  // TODO(srujzs): Modify this once interop has random hash codes.
+  hashCode = js.hashCode;
+  expect(hashCode, 0);
+  expect(hashCode, js.hashCode);
+  expect(js.toString, isNotNull);
+  // Should forward to underlying `toString` call.
+  expect(js.toString(), '[object Object]');
+  expect(js.noSuchMethod, isNotNull);
+  noSuchMethodErrorThrown = true;
+  try {
+    (js as dynamic).triggerNoSuchMethod();
+    noSuchMethodErrorThrown = false;
+  } catch (_) {}
+  expect(noSuchMethodErrorThrown, isTrue);
+  expect(js.runtimeType, JSObject);
+}

tests/web/web.status

@@ -27,12 +27,16 @@ deferred_split_test: Slow, Pass # Issue 25940
 [ $compiler == dart2js && $runtime == chrome && $csp ]
 deferred/load_in_correct_order_test: SkipByDesign # Purposely uses `eval`
 
+[ $compiler == dart2js && $runtime == d8 ]
+internal/object_members_test: SkipByDesign # Browser test
+
 [ $compiler == dart2js && $runtime == ff && $system == windows ]
 consistent_index_error_string_test: Slow, Pass # Issue 25940
 
 [ $compiler == dart2js && $csp ]
 deferred_custom_loader_test: SkipByDesign # Issue 25683
 deferred_fail_and_retry_test: SkipByDesign # Uses eval to simulate failed loading.
+internal/object_members_test: SkipByDesign # Uses eval for interop
 
 [ $compiler == dart2js && !$host_checked ]
 dummy_compiler_test: Slow, Pass # Issue 32439. self-hosting doesn't work with CFE yet.

tests/web_2/internal/object_members_test.dart

@@ -0,0 +1,80 @@
+// Copyright (c) 2022, 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.
+
+// Make sure `Object` methods work as expected with `dart:html` and interop
+// types. The expectations here aren't guarantees that they should work a
+// particular way, but rather a way to monitor regressions/changes.
+
+@JS()
+library object_members_test;
+
+import 'package:js/js.dart';
+import 'package:expect/minitest.dart';
+
+import 'dart:html';
+import 'dart:_interceptors' show JSObject;
+
+@JS()
+external void eval(String code);
+
+@JS()
+class JSClass {
+  external JSClass();
+}
+
+void main() {
+  eval(r'''
+    function JSClass() {}
+  ''');
+
+  // `dart:html` type.
+  var div = document.createElement('div');
+  expect(div == div, true);
+  expect(div == DomPointReadOnly(), false);
+  // Ensure that we get a random hash for each new instance. It should be
+  // improbable for this to fail across many runs if the hash is
+  // non-deterministic.
+  var hashCode = div.hashCode;
+  var attempts = 0;
+  var maxAttempts = 1000;
+  while (div.hashCode == hashCode && attempts < maxAttempts) {
+    div = document.createElement('div');
+    attempts++;
+  }
+  expect(attempts > 0 && attempts != maxAttempts, isTrue);
+  expect(div.toString, isNotNull);
+  expect(div.toString(), 'div');
+  expect(div.noSuchMethod, isNotNull);
+  var noSuchMethodErrorThrown = true;
+  try {
+    (div as dynamic).triggerNoSuchMethod();
+    noSuchMethodErrorThrown = false;
+  } catch (_) {}
+  expect(noSuchMethodErrorThrown, isTrue);
+  expect(div.runtimeType, DivElement);
+
+  // `toString` for `dart:html` types that do not have an overridden `toString`
+  // should look up the type through the proto.
+  expect(window.navigator.toString(), "Instance of 'Navigator'");
+
+  // Interop type.
+  var js = JSClass();
+  expect(js == js, true);
+  expect(js == JSClass(), false);
+  // TODO(srujzs): Modify this once interop has random hash codes.
+  hashCode = js.hashCode;
+  expect(hashCode, 0);
+  expect(hashCode, js.hashCode);
+  expect(js.toString, isNotNull);
+  // Should forward to underlying `toString` call.
+  expect(js.toString(), '[object Object]');
+  expect(js.noSuchMethod, isNotNull);
+  noSuchMethodErrorThrown = true;
+  try {
+    (js as dynamic).triggerNoSuchMethod();
+    noSuchMethodErrorThrown = false;
+  } catch (_) {}
+  expect(noSuchMethodErrorThrown, isTrue);
+  expect(js.runtimeType, JSObject);
+}

tests/web_2/web_2.status

@@ -27,12 +27,16 @@ deferred_split_test: Slow, Pass # Issue 25940
 [ $compiler == dart2js && $runtime == chrome && $csp ]
 deferred/load_in_correct_order_test: SkipByDesign # Purposely uses `eval`
 
+[ $compiler == dart2js && $runtime == d8 ]
+internal/object_members_test: SkipByDesign # Browser test
+
 [ $compiler == dart2js && $runtime == ff && $system == windows ]
 consistent_index_error_string_test: Slow, Pass # Issue 25940
 
 [ $compiler == dart2js && $csp ]
 deferred_custom_loader_test: SkipByDesign # Issue 25683
 deferred_fail_and_retry_test: SkipByDesign # Uses eval to simulate failed loading.
+internal/object_members_test: SkipByDesign # Uses eval for interop
 
 [ $compiler == dart2js && !$host_checked ]
 dummy_compiler_test: Slow, Pass # Issue 32439. self-hosting doesn't work with CFE yet.