PointerDeviceKind and ui.PointerChange forwards-compatibility (#97350)

* PointerDeviceKind and ui.PointerChange forwards-compatibility

* Add link to trackpad gestures issue

* Add TODO

packages/flutter/lib/src/gestures/converter.dart

@@ -21,6 +21,8 @@ int _synthesiseDownButtons(int buttons, PointerDeviceKind kind) {
     case PointerDeviceKind.invertedStylus:
       return buttons == 0 ? kPrimaryButton : buttons;
     case PointerDeviceKind.unknown:
+    default: // ignore: no_default_cases, to allow adding new device types to [PointerDeviceKind]
+             // TODO(moffatman): Remove after landing https://github.com/flutter/flutter/issues/23604
       // We have no information about the device but we know we never want
       // buttons to be 0 when the pointer is down.
       return buttons == 0 ? kPrimaryButton : buttons;
@@ -207,6 +209,9 @@ class PointerEventConverter {
                     radiusMax: radiusMax,
                     embedderId: datum.embedderId,
                   );
+                default: // ignore: no_default_cases, to allow adding new pointer events to [ui.PointerChange]
+                         // TODO(moffatman): Remove after landing https://github.com/flutter/flutter/issues/23604
+                  throw StateError('Unreachable');
               }
             case ui.PointerSignalKind.scroll:
               final Offset scrollDelta =

packages/flutter/lib/src/gestures/events.dart

@@ -2108,6 +2108,8 @@ double computeHitSlop(PointerDeviceKind kind, DeviceGestureSettings? settings) {
     case PointerDeviceKind.invertedStylus:
     case PointerDeviceKind.unknown:
     case PointerDeviceKind.touch:
+    default: // ignore: no_default_cases, to allow adding new device types to [PointerDeviceKind]
+             // TODO(moffatman): Remove after landing https://github.com/flutter/flutter/issues/23604
       return settings?.touchSlop ?? kTouchSlop;
   }
 }
@@ -2121,6 +2123,8 @@ double computePanSlop(PointerDeviceKind kind, DeviceGestureSettings? settings) {
     case PointerDeviceKind.invertedStylus:
     case PointerDeviceKind.unknown:
     case PointerDeviceKind.touch:
+    default: // ignore: no_default_cases, to allow adding new device types to [PointerDeviceKind]
+             // TODO(moffatman): Remove after landing https://github.com/flutter/flutter/issues/23604
       return settings?.panSlop ?? kPanSlop;
   }
 }
@@ -2134,6 +2138,8 @@ double computeScaleSlop(PointerDeviceKind kind) {
     case PointerDeviceKind.invertedStylus:
     case PointerDeviceKind.unknown:
     case PointerDeviceKind.touch:
+    default: // ignore: no_default_cases, to allow adding new device types to [PointerDeviceKind]
+             // TODO(moffatman): Remove after landing https://github.com/flutter/flutter/issues/23604
       return kScaleSlop;
   }
 }

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

@@ -653,6 +653,8 @@ class _AndroidMotionEventConverter {
         toolType = AndroidPointerProperties.kToolTypeEraser;
         break;
       case PointerDeviceKind.unknown:
+      default: // ignore: no_default_cases, to allow adding new device types to [PointerDeviceKind]
+               // TODO(moffatman): Remove after landing https://github.com/flutter/flutter/issues/23604
         toolType = AndroidPointerProperties.kToolTypeUnknown;
         break;
     }

packages/flutter/lib/src/widgets/focus_manager.dart

@@ -1649,6 +1649,8 @@ class FocusManager with DiagnosticableTreeMixin, ChangeNotifier {
         break;
       case PointerDeviceKind.mouse:
       case PointerDeviceKind.unknown:
+      default: // ignore: no_default_cases, to allow adding new device types to [PointerDeviceKind]
+               // TODO(moffatman): Remove after landing https://github.com/flutter/flutter/issues/23604
         _lastInteractionWasTouch = false;
         expectedMode = FocusHighlightMode.traditional;
         break;

packages/flutter/lib/src/widgets/scrollbar.dart

@@ -668,6 +668,8 @@ class ScrollbarPainter extends ChangeNotifier implements CustomPainter {
       case PointerDeviceKind.stylus:
       case PointerDeviceKind.invertedStylus:
       case PointerDeviceKind.unknown:
+      default: // ignore: no_default_cases, to allow adding new device types to [PointerDeviceKind]
+               // TODO(moffatman): Remove after landing https://github.com/flutter/flutter/issues/23604
         return interactiveRect.contains(position);
     }
   }
@@ -700,6 +702,8 @@ class ScrollbarPainter extends ChangeNotifier implements CustomPainter {
       case PointerDeviceKind.stylus:
       case PointerDeviceKind.invertedStylus:
       case PointerDeviceKind.unknown:
+      default: // ignore: no_default_cases, to allow adding new device types to [PointerDeviceKind]
+               // TODO(moffatman): Remove after landing https://github.com/flutter/flutter/issues/23604
         return _thumbRect!.contains(position);
     }
   }
@@ -1936,6 +1940,8 @@ class RawScrollbarState<T extends RawScrollbar> extends State<T> with TickerProv
                   case PointerDeviceKind.invertedStylus:
                   case PointerDeviceKind.unknown:
                   case PointerDeviceKind.touch:
+                  default: // ignore: no_default_cases, to allow adding new device types to [PointerDeviceKind]
+                           // TODO(moffatman): Remove after landing https://github.com/flutter/flutter/issues/23604
                     break;
                 }
               },
@@ -1949,6 +1955,8 @@ class RawScrollbarState<T extends RawScrollbar> extends State<T> with TickerProv
                   case PointerDeviceKind.invertedStylus:
                   case PointerDeviceKind.unknown:
                   case PointerDeviceKind.touch:
+                  default: // ignore: no_default_cases, to allow adding new device types to [PointerDeviceKind]
+                           // TODO(moffatman): Remove after landing https://github.com/flutter/flutter/issues/23604
                     break;
                 }
               },

packages/flutter/lib/src/widgets/text_selection.dart

@@ -1145,6 +1145,8 @@ class TextSelectionGestureDetectorBuilder {
               break;
             case PointerDeviceKind.touch:
             case PointerDeviceKind.unknown:
+            default: // ignore: no_default_cases, to allow adding new device types to [PointerDeviceKind]
+                     // TODO(moffatman): Remove after landing https://github.com/flutter/flutter/issues/23604
               // On macOS/iOS/iPadOS a touch tap places the cursor at the edge
               // of the word.
               renderEditable.selectWordEdge(cause: SelectionChangedCause.tap);