[Keyboard, Windows] Fix that IME events are still dispatched to FocusNode.onKey (#104244)

Author: dkwingsmt

packages/flutter/lib/src/services/hardware_keyboard.dart

@@ -766,6 +766,11 @@ class KeyEventManager {
   // dispatchable [RawKeyEvent] is available.
   final List<KeyEvent> _keyEventsSinceLastMessage = <KeyEvent>[];
 
+  // When a RawKeyDownEvent is skipped ([RawKeyEventData.shouldDispatchEvent]
+  // is false), its physical key will be recorded here, so that its up event
+  // can also be properly skipped.
+  final Set<PhysicalKeyboardKey> _skippedRawKeysPressed = <PhysicalKeyboardKey>{};
+
   /// Dispatch a key data to global and leaf listeners.
   ///
   /// This method is the handler to the global `onKeyData` API.
@@ -843,21 +848,40 @@ class KeyEventManager {
       _rawKeyboard.addListener(_convertRawEventAndStore);
     }
     final RawKeyEvent rawEvent = RawKeyEvent.fromMessage(message as Map<String, dynamic>);
-    // The following `handleRawKeyEvent` will call `_convertRawEventAndStore`
-    // unless the event is not dispatched.
-    bool handled = _rawKeyboard.handleRawKeyEvent(rawEvent);
 
-    for (final KeyEvent event in _keyEventsSinceLastMessage) {
-      handled = _hardwareKeyboard.handleKeyEvent(event) || handled;
-    }
-    if (_transitMode == KeyDataTransitMode.rawKeyData) {
-      assert(setEquals(_rawKeyboard.physicalKeysPressed, _hardwareKeyboard.physicalKeysPressed),
-        'RawKeyboard reported ${_rawKeyboard.physicalKeysPressed}, '
-        'while HardwareKeyboard reported ${_hardwareKeyboard.physicalKeysPressed}');
+    bool shouldDispatch = true;
+    if (rawEvent is RawKeyDownEvent) {
+      if (!rawEvent.data.shouldDispatchEvent()) {
+        shouldDispatch = false;
+        _skippedRawKeysPressed.add(rawEvent.physicalKey);
+      } else {
+        _skippedRawKeysPressed.remove(rawEvent.physicalKey);
+      }
+    } else if (rawEvent is RawKeyUpEvent) {
+      if (_skippedRawKeysPressed.contains(rawEvent.physicalKey)) {
+        _skippedRawKeysPressed.remove(rawEvent.physicalKey);
+        shouldDispatch = false;
+      }
     }
 
-    handled = _dispatchKeyMessage(_keyEventsSinceLastMessage, rawEvent) || handled;
-    _keyEventsSinceLastMessage.clear();
+    bool handled = true;
+    if (shouldDispatch) {
+      // The following `handleRawKeyEvent` will call `_convertRawEventAndStore`
+      // unless the event is not dispatched.
+      handled = _rawKeyboard.handleRawKeyEvent(rawEvent);
+
+      for (final KeyEvent event in _keyEventsSinceLastMessage) {
+        handled = _hardwareKeyboard.handleKeyEvent(event) || handled;
+      }
+      if (_transitMode == KeyDataTransitMode.rawKeyData) {
+        assert(setEquals(_rawKeyboard.physicalKeysPressed, _hardwareKeyboard.physicalKeysPressed),
+          'RawKeyboard reported ${_rawKeyboard.physicalKeysPressed}, '
+          'while HardwareKeyboard reported ${_hardwareKeyboard.physicalKeysPressed}');
+      }
+
+      handled = _dispatchKeyMessage(_keyEventsSinceLastMessage, rawEvent) || handled;
+      _keyEventsSinceLastMessage.clear();
+    }
 
     return <String, dynamic>{ 'handled': handled };
   }

packages/flutter/lib/src/services/raw_keyboard.dart

@@ -661,27 +661,13 @@ class RawKeyboard {
   /// Process a new [RawKeyEvent] by recording the state changes and
   /// dispatching to listeners.
   bool handleRawKeyEvent(RawKeyEvent event) {
-    bool shouldDispatch = true;
     if (event is RawKeyDownEvent) {
-      if (event.data.shouldDispatchEvent()) {
-        _keysPressed[event.physicalKey] = event.logicalKey;
-      } else {
-        shouldDispatch = false;
-        _hiddenKeysPressed.add(event.physicalKey);
-      }
+      _keysPressed[event.physicalKey] = event.logicalKey;
     } else if (event is RawKeyUpEvent) {
-      if (!_hiddenKeysPressed.contains(event.physicalKey)) {
-        // Use the physical key in the key up event to find the physical key from
-        // the corresponding key down event and remove it, even if the logical
-        // keys don't match.
-        _keysPressed.remove(event.physicalKey);
-      } else {
-        _hiddenKeysPressed.remove(event.physicalKey);
-        shouldDispatch = false;
-      }
-    }
-    if (!shouldDispatch) {
-      return true;
+      // Use the physical key in the key up event to find the physical key from
+      // the corresponding key down event and remove it, even if the logical
+      // keys don't match.
+      _keysPressed.remove(event.physicalKey);
     }
     // Make sure that the modifiers reflect reality, in case a modifier key was
     // pressed/released while the app didn't have focus.
@@ -855,7 +841,6 @@ class RawKeyboard {
   }
 
   final Map<PhysicalKeyboardKey, LogicalKeyboardKey> _keysPressed = <PhysicalKeyboardKey, LogicalKeyboardKey>{};
-  final Set<PhysicalKeyboardKey> _hiddenKeysPressed = <PhysicalKeyboardKey>{};
 
   /// Returns the set of keys currently pressed.
   Set<LogicalKeyboardKey> get keysPressed => _keysPressed.values.toSet();

packages/flutter/test/services/raw_keyboard_test.dart

@@ -1936,6 +1936,28 @@ void main() {
       const  String platform = 'windows';
       bool lastHandled = true;
       final List<RawKeyEvent> events = <RawKeyEvent>[];
+
+      // Test both code paths: addListener, and FocusNode.onKey.
+      RawKeyboard.instance.addListener(events.add);
+      final FocusNode node = FocusNode(
+        onKey: (_, RawKeyEvent event) {
+          events.add(event);
+          return KeyEventResult.ignored;
+        },
+      );
+      await tester.pumpWidget(RawKeyboardListener(
+        focusNode: node,
+        child: Container(),
+      ));
+      node.requestFocus();
+      await tester.pumpAndSettle();
+
+      // Dispatch an arbitrary key press for the correct transit mode.
+      await simulateKeyDownEvent(LogicalKeyboardKey.keyA);
+      await simulateKeyUpEvent(LogicalKeyboardKey.keyA);
+      expect(events, hasLength(4));
+      events.clear();
+
       // Simulate raw events because VK_PROCESSKEY does not exist in the key mapping.
       Future<void> simulateKeyEventMessage(String type, int keyCode, int scanCode) {
         return ServicesBinding.instance.defaultBinaryMessenger.handlePlatformMessage(
@@ -1953,7 +1975,7 @@ void main() {
           },
         );
       }
-      RawKeyboard.instance.addListener(events.add);
+
       await simulateKeyEventMessage('keydown', 229, 30);
       expect(events, isEmpty);
       expect(lastHandled, true);
@@ -1962,7 +1984,7 @@ void main() {
       expect(events, isEmpty);
       expect(lastHandled, true);
       expect(RawKeyboard.instance.keysPressed, isEmpty);
-    });
+    }, variant: KeySimulatorTransitModeVariant.keyDataThenRawKeyData());
 
     test('data.toString', () {
       expect(RawKeyEvent.fromMessage(const <String, Object?>{