[rti/js_interop] Redo: Accelerate is JSObject

Change-Id: I9a252319a1c7b426a54d52660c9d8adc5e72cd2b
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/425334
Reviewed-by: Srujan Gaddam <[email protected]>
Commit-Queue: Stephen Adams <[email protected]>

Author: rakudrama

sdk/lib/_internal/js_shared/lib/rti.dart

@@ -18,7 +18,7 @@ import 'dart:_foreign_helper'
         RAW_DART_FUNCTION_REF,
         TYPE_REF;
 import 'dart:_interceptors'
-    show JavaScriptFunction, JSArray, JSNull, JSUnmodifiableArray;
+    show JavaScriptFunction, JSArray, JSNull, JSUnmodifiableArray, JSObject;
 import 'dart:_js_helper'
     as records
     show createRecordTypePredicate, getRtiForRecord;
@@ -1267,6 +1267,9 @@ bool _installSpecializedIsTest(Object? object) {
           RAW_DART_FUNCTION_REF(_isListTestViaProperty),
         );
       }
+      if (_Utils.isIdentical(testRti, TYPE_REF<JSObject>())) {
+        return _finishIsFn(testRti, object, RAW_DART_FUNCTION_REF(_isJSObject));
+      }
       return _finishIsFn(
         testRti,
         object,
@@ -1432,6 +1435,40 @@ bool _isListTestViaProperty(Object? object) {
   return JS('bool', '!!#[#]', interceptor, tag);
 }
 
+/// Specialized test for JSObject that avoids the uncached interceptor for plain
+/// JavaScript objects.
+///
+/// Based on [_isTestViaProperty] to handle mocks and fakes defined in Dart.
+bool _isJSObject(Object? object) {
+  // This static method is installed on an Rti object as a JavaScript instance
+  // method. The Rti object is 'this'.
+  Rti testRti = _Utils.asRti(JS('', 'this'));
+  if (object == null) return false;
+  if (JS('bool', 'typeof # == "object"', object)) {
+    if (_isDartObject(object)) {
+      // This path includes dart2js functions which are objects that extend
+      // `Closure`.
+      //
+      // Some Dart objects implement a subtype of JSObject, e.g. a Mock that
+      // implements Window from `dart:html`. This test would be unnecessary of
+      // the only form of js_interop was `dart:js_interop`.
+      var tag = Rti._getSpecializedTestResource(testRti);
+      return JS('bool', '!!#[#]', object, tag);
+    }
+    return true;
+  }
+  if (JS('bool', 'typeof # == "function"', object)) {
+    if (JS_GET_FLAG('DEV_COMPILER')) {
+      // DDC functions are JavaScript functions, but have a signature attached.
+      var signatureName = JS_GET_NAME(JsGetName.SIGNATURE_NAME);
+      var signature = JS('', '#[#]', object, signatureName);
+      return signature == null;
+    }
+    return true;
+  }
+  return false;
+}
+
 /// General unspecialized 'as' check that works for any type.
 /// Called from generated code.
 @pragma('dart2js:stack-starts-at-throw')

tests/web/internal/html_mocks_with_static_interop_test.dart

@@ -0,0 +1,48 @@
+// Copyright (c) 2025, 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.
+
+// Tests that Dart mocks for `dart:html` classes are recognized as
+// `dart:js_interop` JSObjects.
+//
+// This is expected to work for DDC and dart2js but not dart2wasm.
+
+import 'package:expect/expect.dart';
+
+import 'dart:js_interop' as dartJsInterop;
+import 'dart:html' show window, Window, Document, HtmlDocument;
+
+class MockWindow implements Window {
+  Document get document => MockDocument();
+
+  noSuchMethod(Invocation invocation) => super.noSuchMethod(invocation);
+}
+
+class MockDocument implements HtmlDocument {
+  noSuchMethod(Invocation invocation) => super.noSuchMethod(invocation);
+}
+
+void main() {
+  test(MockWindow(), true);
+  test(window, false);
+}
+
+void test(Window w, bool isMock) {
+  Expect.type<Window>(w);
+  Expect.type<dartJsInterop.JSObject>(w);
+
+  final doc = w.document;
+
+  Expect.type<HtmlDocument>(doc);
+  Expect.type<dartJsInterop.JSObject>(doc);
+
+  if (isMock) {
+    Expect.type<MockWindow>(w);
+    Expect.type<MockDocument>(doc);
+    Expect.isTrue(w is MockWindow);
+    Expect.isTrue(doc is MockDocument);
+  } else {
+    Expect.isFalse(w is MockWindow);
+    Expect.isFalse(doc is MockDocument);
+  }
+}

tests/web/web.status

@@ -34,6 +34,7 @@ constant_javascript_semantics2_test: Slow, Pass # Issue 25940
 deferred_split_test: Slow, Pass # Issue 25940
 
 [ $compiler == dart2js && $runtime == d8 ]
+internal/html_mocks_with_static_interop_test: SkipByDesign # Browser test
 internal/object_members_test: SkipByDesign # Browser test
 
 [ $compiler == dart2js && $runtime == ff && $system == windows ]
@@ -61,7 +62,7 @@ wasm/source_map_simple_optimized_test: SkipByDesign # Reads source map file usin
 wasm/source_map_simple_test: SkipByDesign # Reads source map file using d8's readbuffer
 wasm/uri_base_test: SkipByDesign # Converts Uri.base to file path
 
-[ $compiler == dart2wasm && ( $runtime == d8 || $runtime == jsc || $runtime == jsshell ) ]
+[ $compiler == dart2wasm && ($runtime == d8 || $runtime == jsc || $runtime == jsshell) ]
 wasm/multi_module_stress_test: SkipByDesign # DataView fails to load necessary input file.
 
 [ $compiler == dartk && $runtime == vm ]