flutter: shift after one shot IME capitalization (#14695)

* flutter: shift after one shot IME capitalization

Signed-off-by: Amirhossein Akhlaghpour <m9.akhlaghpoor@gmail.com>

* flutter: clarify stale mobile shift handling

Signed-off-by: Amirhossein Akhlaghpour <m9.akhlaghpoor@gmail.com>

* fix(android): gboard shift stuck

Signed-off-by: fufesou <linlong1266@gmail.com>

* fix(android): gboard shift stuck, remove unused param

Signed-off-by: fufesou <linlong1266@gmail.com>

* fix(android): gboard shift stuck, release shift before sending events

Signed-off-by: fufesou <linlong1266@gmail.com>

* chore(flutter): document stale mobile shift release flow

Signed-off-by: Amirhossein Akhlaghpour <m9.akhlaghpoor@gmail.com>

---------

Signed-off-by: Amirhossein Akhlaghpour <m9.akhlaghpoor@gmail.com>
Signed-off-by: fufesou <linlong1266@gmail.com>
Co-authored-by: fufesou <linlong1266@gmail.com>

flutter/lib/models/input_model.dart

@@ -2,6 +2,7 @@ import 'dart:async';
 import 'dart:convert';
 import 'dart:io';
 import 'dart:math';
+import 'package:flutter/foundation.dart';
 import 'dart:ui' as ui;
 
 import 'package:desktop_multi_window/desktop_multi_window.dart';
@@ -15,6 +16,7 @@ import 'package:get/get.dart';
 import '../../models/model.dart';
 import '../../models/platform_model.dart';
 import '../../models/state_model.dart';
+import 'input_modifier_utils.dart';
 import 'relative_mouse_model.dart';
 import '../common.dart';
 import '../consts.dart';
@@ -697,6 +699,38 @@ class InputModel {
     }
   }
 
+  // Safe: this only re-dispatches synthesized Shift key-up events.
+  // The key-up path clears the tracked Shift state so this does not loop.
+  void _releaseTrackedShiftKeyEventIfNeeded() {
+    final leftShift = toReleaseKeys.lastLShiftKeyEvent;
+    final rightShift = toReleaseKeys.lastRShiftKeyEvent;
+    if (leftShift != null) {
+      handleKeyEvent(leftShift);
+    }
+    if (rightShift != null) {
+      handleKeyEvent(rightShift);
+    }
+  }
+
+  // Safe: this only re-dispatches synthesized Shift key-up events.
+  // The raw key-up path clears the tracked Shift state so this does not loop.
+  void _releaseTrackedRawShiftKeyEventIfNeeded() {
+    final leftShift = toReleaseRawKeys.lastLShiftKeyEvent;
+    final rightShift = toReleaseRawKeys.lastRShiftKeyEvent;
+    if (leftShift != null) {
+      handleRawKeyEvent(RawKeyUpEvent(
+        data: leftShift.data,
+        character: leftShift.character,
+      ));
+    }
+    if (rightShift != null) {
+      handleRawKeyEvent(RawKeyUpEvent(
+        data: rightShift.data,
+        character: rightShift.character,
+      ));
+    }
+  }
+
   KeyEventResult handleRawKeyEvent(RawKeyEvent e) {
     if (isViewOnly) return KeyEventResult.handled;
     if (isViewCamera) return KeyEventResult.handled;
@@ -751,6 +785,27 @@ class InputModel {
       toReleaseRawKeys.updateKeyUp(key, e);
     }
 
+    // On some mobile soft-keyboard paths, Flutter may leave cached Shift state
+    // set even though the current raw key event is not shifted anymore.
+    if (e is RawKeyDownEvent &&
+        shouldReleaseStaleMobileShift(
+          isMobile: isMobile,
+          cachedShiftPressed: shift,
+          actualShiftPressed: e.isShiftPressed,
+          logicalKey: e.logicalKey,
+          hasTrackedShiftKeyDown: toReleaseRawKeys.lastLShiftKeyEvent != null ||
+              toReleaseRawKeys.lastRShiftKeyEvent != null,
+        )) {
+      if (kDebugMode) {
+        debugPrint(
+          'input: releasing stale mobile Shift before replaying tracked raw '
+          'key-up (logicalKey=${e.logicalKey.keyLabel}, '
+          'actualShiftPressed=${e.isShiftPressed}, cachedShiftPressed=$shift)',
+        );
+      }
+      _releaseTrackedRawShiftKeyEventIfNeeded();
+    }
+
     // * Currently mobile does not enable map mode
     if ((isDesktop || isWebDesktop) && keyboardMode == kKeyMapMode) {
       mapKeyboardModeRaw(e, iosCapsLock);
@@ -794,6 +849,8 @@ class InputModel {
       iosCapsLock = _getIosCapsFromCharacter(e);
     }
 
+    // Update cached modifier state before sending the event. The stale mobile
+    // Shift release check below relies on this cached state.
     if (e is KeyUpEvent) {
       handleKeyUpEventModifiers(e);
     } else if (e is KeyDownEvent) {
@@ -831,6 +888,21 @@ class InputModel {
         }
       }
     }
+
+    // On some mobile soft-keyboard paths, Flutter may leave cached Shift state
+    // set even though the current key event is not shifted anymore.
+    if (e is KeyDownEvent &&
+        shouldReleaseStaleMobileShift(
+          isMobile: isMobile,
+          cachedShiftPressed: shift,
+          actualShiftPressed: HardwareKeyboard.instance.isShiftPressed,
+          logicalKey: e.logicalKey,
+          hasTrackedShiftKeyDown: toReleaseKeys.lastLShiftKeyEvent != null ||
+              toReleaseKeys.lastRShiftKeyEvent != null,
+        )) {
+      _releaseTrackedShiftKeyEventIfNeeded();
+    }
+
     final isDesktopAndMapMode =
         isDesktop || (isWebDesktop && keyboardMode == kKeyMapMode);
     if (isMobileAndMapMode || isDesktopAndMapMode) {

flutter/lib/models/input_modifier_utils.dart

@@ -0,0 +1,38 @@
+import 'package:flutter/services.dart';
+
+/// Returns true when a stale mobile one-shot Shift state should be released
+/// by replaying a tracked Shift key-down as a synthesized key-up.
+///
+/// This is only valid on mobile when Flutter's cached Shift state is still on
+/// (`cachedShiftPressed == true`) but the current hardware/raw event reports
+/// Shift as off (`actualShiftPressed == false`).
+///
+/// A tracked Shift key-down is required so the caller can safely synthesize the
+/// matching key-up. Both `shiftLeft` and `shiftRight` are excluded because the
+/// Shift key event itself must be processed first; otherwise we could release
+/// the tracked key while still handling the original Shift press/release.
+/// Callers should evaluate this only after their cached modifier state has been
+/// updated for the current event.
+///
+/// When this returns true, the caller logs a line like:
+/// `input: releasing stale mobile Shift before replaying tracked raw key-up`
+/// immediately before calling `_releaseTrackedRawShiftKeyEventIfNeeded()`.
+bool shouldReleaseStaleMobileShift({
+  required bool isMobile,
+  required bool cachedShiftPressed,
+  required bool actualShiftPressed,
+  required LogicalKeyboardKey logicalKey,
+  required bool hasTrackedShiftKeyDown,
+}) {
+  if (!isMobile || !cachedShiftPressed || actualShiftPressed) {
+    return false;
+  }
+  if (!hasTrackedShiftKeyDown) {
+    return false;
+  }
+  if (logicalKey == LogicalKeyboardKey.shiftLeft ||
+      logicalKey == LogicalKeyboardKey.shiftRight) {
+    return false;
+  }
+  return true;
+}

flutter/pubspec.yaml

@@ -113,8 +113,8 @@ dependencies:
 
 dev_dependencies:
   icons_launcher: ^2.0.4
-  #flutter_test:
-  #sdk: flutter
+  flutter_test:
+    sdk: flutter
   build_runner: ^2.4.6
   freezed: ^2.4.2
   flutter_lints: ^2.0.2

flutter/test/input_modifier_utils_test.dart

@@ -0,0 +1,125 @@
+import 'package:flutter/services.dart';
+import 'package:flutter_test/flutter_test.dart';
+import 'package:flutter_hbb/models/input_modifier_utils.dart';
+
+void main() {
+  group('shouldReleaseStaleMobileShift', () {
+    test('does not release when cached shift is already false', () {
+      expect(
+        shouldReleaseStaleMobileShift(
+          isMobile: true,
+          cachedShiftPressed: false,
+          actualShiftPressed: false,
+          logicalKey: LogicalKeyboardKey.keyD,
+          hasTrackedShiftKeyDown: true,
+        ),
+        isFalse,
+      );
+    });
+
+    test('releases one-shot mobile shift after a text key', () {
+      expect(
+        shouldReleaseStaleMobileShift(
+          isMobile: true,
+          cachedShiftPressed: true,
+          actualShiftPressed: false,
+          logicalKey: LogicalKeyboardKey.keyD,
+          hasTrackedShiftKeyDown: true,
+        ),
+        isTrue,
+      );
+    });
+
+    test('does not release manually toggled shift without tracked key down',
+        () {
+      expect(
+        shouldReleaseStaleMobileShift(
+          isMobile: true,
+          cachedShiftPressed: true,
+          actualShiftPressed: false,
+          logicalKey: LogicalKeyboardKey.keyD,
+          hasTrackedShiftKeyDown: false,
+        ),
+        isFalse,
+      );
+    });
+
+    test('does not release when shift is still physically pressed', () {
+      expect(
+        shouldReleaseStaleMobileShift(
+          isMobile: true,
+          cachedShiftPressed: true,
+          actualShiftPressed: true,
+          logicalKey: LogicalKeyboardKey.keyD,
+          hasTrackedShiftKeyDown: true,
+        ),
+        isFalse,
+      );
+    });
+
+    test('does not release on non-mobile platforms', () {
+      expect(
+        shouldReleaseStaleMobileShift(
+          isMobile: false,
+          cachedShiftPressed: true,
+          actualShiftPressed: false,
+          logicalKey: LogicalKeyboardKey.keyD,
+          hasTrackedShiftKeyDown: true,
+        ),
+        isFalse,
+      );
+    });
+
+    test('releases on enter key', () {
+      expect(
+        shouldReleaseStaleMobileShift(
+          isMobile: true,
+          cachedShiftPressed: true,
+          actualShiftPressed: false,
+          logicalKey: LogicalKeyboardKey.enter,
+          hasTrackedShiftKeyDown: true,
+        ),
+        isTrue,
+      );
+    });
+
+    test('releases on arrow key', () {
+      expect(
+        shouldReleaseStaleMobileShift(
+          isMobile: true,
+          cachedShiftPressed: true,
+          actualShiftPressed: false,
+          logicalKey: LogicalKeyboardKey.arrowLeft,
+          hasTrackedShiftKeyDown: true,
+        ),
+        isTrue,
+      );
+    });
+
+    test('does not release on modifier events', () {
+      expect(
+        shouldReleaseStaleMobileShift(
+          isMobile: true,
+          cachedShiftPressed: true,
+          actualShiftPressed: false,
+          logicalKey: LogicalKeyboardKey.shiftLeft,
+          hasTrackedShiftKeyDown: true,
+        ),
+        isFalse,
+      );
+    });
+
+    test('does not release on shiftRight modifier events', () {
+      expect(
+        shouldReleaseStaleMobileShift(
+          isMobile: true,
+          cachedShiftPressed: true,
+          actualShiftPressed: false,
+          logicalKey: LogicalKeyboardKey.shiftRight,
+          hasTrackedShiftKeyDown: true,
+        ),
+        isFalse,
+      );
+    });
+  });
+}