Fix selectWordsInRange when last word is located before the first word (#113224)

packages/flutter/lib/src/rendering/editable.dart

@@ -2066,7 +2066,9 @@ class RenderEditable extends RenderBox with RelayoutWhenSystemFontsChangeMixin,
     selectWordsInRange(from: _lastTapDownPosition!, cause: cause);
   }
 
-  /// Selects the set words of a paragraph in a given range of global positions.
+  /// Selects the set words of a paragraph that intersect a given range of global positions.
+  ///
+  /// The set of words selected are not strictly bounded by the range of global positions.
   ///
   /// The first and last endpoints of the selection will always be at the
   /// beginning and end of a word respectively.
@@ -2076,15 +2078,17 @@ class RenderEditable extends RenderBox with RelayoutWhenSystemFontsChangeMixin,
     assert(cause != null);
     assert(from != null);
     _computeTextMetricsIfNeeded();
-    final TextPosition firstPosition = _textPainter.getPositionForOffset(globalToLocal(from - _paintOffset));
-    final TextSelection firstWord = _getWordAtOffset(firstPosition);
-    final TextSelection lastWord = to == null ?
-      firstWord : _getWordAtOffset(_textPainter.getPositionForOffset(globalToLocal(to - _paintOffset)));
+    final TextPosition fromPosition = _textPainter.getPositionForOffset(globalToLocal(from - _paintOffset));
+    final TextSelection fromWord = _getWordAtOffset(fromPosition);
+    final TextPosition toPosition = to == null ? fromPosition : _textPainter.getPositionForOffset(globalToLocal(to - _paintOffset));
+    final TextSelection toWord = toPosition == fromPosition ? fromWord : _getWordAtOffset(toPosition);
+    final bool isFromWordBeforeToWord = fromWord.start < toWord.end;
+
     _setSelection(
       TextSelection(
-        baseOffset: firstWord.base.offset,
-        extentOffset: lastWord.extent.offset,
-        affinity: firstWord.affinity,
+        baseOffset: isFromWordBeforeToWord ? fromWord.base.offset : fromWord.extent.offset,
+        extentOffset: isFromWordBeforeToWord ? toWord.extent.offset : toWord.base.offset,
+        affinity: fromWord.affinity,
       ),
       cause,
     );

packages/flutter/test/material/text_field_test.dart

@@ -8432,6 +8432,84 @@ void main() {
     variant: const TargetPlatformVariant(<TargetPlatform>{ TargetPlatform.iOS,  TargetPlatform.macOS }),
   );
 
+  testWidgets(
+    'long press drag extends the selection to the word under the drag and shows toolbar on lift on non-Apple platforms',
+    (WidgetTester tester) async {
+      final TextEditingController controller = TextEditingController(
+        text: 'Atwater Peel Sherbrooke Bonaventure',
+      );
+      await tester.pumpWidget(
+        MaterialApp(
+          home: Material(
+            child: Center(
+              child: TextField(
+                controller: controller,
+              ),
+            ),
+          ),
+        ),
+      );
+
+      final TestGesture gesture =
+          await tester.startGesture(textOffsetToPosition(tester, 18));
+      await tester.pump(const Duration(milliseconds: 500));
+
+      // Long press selects the word at the long presses position.
+      expect(
+        controller.selection,
+        const TextSelection(baseOffset: 13, extentOffset: 23),
+      );
+      // Cursor move doesn't trigger a toolbar initially.
+      expect(find.byType(TextButton), findsNothing);
+
+      await gesture.moveBy(const Offset(100, 0));
+      await tester.pump();
+
+      // The selection is now moved with the drag.
+      expect(
+        controller.selection,
+        const TextSelection(baseOffset: 13, extentOffset: 35),
+      );
+      // Still no toolbar.
+      expect(find.byType(TextButton), findsNothing);
+
+      // The selection is moved on a backwards drag.
+      await gesture.moveBy(const Offset(-200, 0));
+      await tester.pump();
+
+      // The selection is now moved with the drag.
+      expect(
+        controller.selection,
+        const TextSelection(baseOffset: 23, extentOffset: 8),
+      );
+      // Still no toolbar.
+      expect(find.byType(TextButton), findsNothing);
+
+      await gesture.moveBy(const Offset(-100, 0));
+      await tester.pump();
+
+      // The selection is now moved with the drag.
+      expect(
+        controller.selection,
+        const TextSelection(baseOffset: 23, extentOffset: 0),
+      );
+      // Still no toolbar.
+      expect(find.byType(TextButton), findsNothing);
+
+      await gesture.up();
+      await tester.pumpAndSettle();
+
+      // The selection isn't affected by the gesture lift.
+      expect(
+        controller.selection,
+        const TextSelection(baseOffset: 23, extentOffset: 0),
+      );
+      // The toolbar now shows up.
+      expect(find.byType(TextButton), isContextMenuProvidedByPlatform ? findsNothing : findsNWidgets(4));
+    },
+    variant: TargetPlatformVariant.all(excluding: <TargetPlatform>{ TargetPlatform.iOS, TargetPlatform.macOS }),
+  );
+
   testWidgets(
     'long press drag moves the cursor under the drag and shows toolbar on lift',
     (WidgetTester tester) async {

packages/flutter/test/widgets/selectable_text_test.dart

@@ -3372,7 +3372,7 @@ void main() {
   );
 
   testWidgets(
-    'long press drag moves the cursor under the drag and shows toolbar on lift (iOS)',
+    'long press drag extends the selection to the word under the drag and shows toolbar on lift on non-Apple platforms',
     (WidgetTester tester) async {
       await tester.pumpWidget(
         const MaterialApp(
@@ -3384,10 +3384,84 @@ void main() {
         ),
       );
 
-      final Offset selectableTextStart = tester.getTopLeft(find.byType(SelectableText));
+      final TestGesture gesture =
+          await tester.startGesture(textOffsetToPosition(tester, 18));
+      await tester.pump(const Duration(milliseconds: 500));
+
+      final EditableText editableTextWidget = tester.widget(find.byType(EditableText).first);
+      final TextEditingController controller = editableTextWidget.controller;
+
+      // Long press selects the word at the long presses position.
+      expect(
+        controller.selection,
+        const TextSelection(baseOffset: 13, extentOffset: 23),
+      );
+      // Cursor move doesn't trigger a toolbar initially.
+      expect(find.byType(TextButton), findsNothing);
+
+      await gesture.moveBy(const Offset(100, 0));
+      await tester.pump();
+
+      // The selection is now moved with the drag.
+      expect(
+        controller.selection,
+        const TextSelection(baseOffset: 13, extentOffset: 35),
+      );
+      // Still no toolbar.
+      expect(find.byType(TextButton), findsNothing);
+
+      // The selection is moved on a backwards drag.
+      await gesture.moveBy(const Offset(-200, 0));
+      await tester.pump();
+
+      // The selection is now moved with the drag.
+      expect(
+        controller.selection,
+        const TextSelection(baseOffset: 23, extentOffset: 8),
+      );
+      // Still no toolbar.
+      expect(find.byType(TextButton), findsNothing);
+
+      await gesture.moveBy(const Offset(-100, 0));
+      await tester.pump();
+
+      // The selection is now moved with the drag.
+      expect(
+        controller.selection,
+        const TextSelection(baseOffset: 23, extentOffset: 0),
+      );
+      // Still no toolbar.
+      expect(find.byType(TextButton), findsNothing);
+
+      await gesture.up();
+      await tester.pumpAndSettle();
+
+      // The selection isn't affected by the gesture lift.
+      expect(
+        controller.selection,
+        const TextSelection(baseOffset: 23, extentOffset: 0),
+      );
+      // The toolbar now shows up.
+      expect(find.byType(TextButton), findsNWidgets(2));
+    },
+    variant: TargetPlatformVariant.all(excluding: <TargetPlatform>{ TargetPlatform.iOS, TargetPlatform.macOS }),
+  );
+
+  testWidgets(
+    'long press drag extends the selection to the word under the drag and shows toolbar on lift (iOS)',
+    (WidgetTester tester) async {
+      await tester.pumpWidget(
+        const MaterialApp(
+          home: Material(
+            child: Center(
+              child: SelectableText('Atwater Peel Sherbrooke Bonaventure'),
+            ),
+          ),
+        ),
+      );
 
       final TestGesture gesture =
-      await tester.startGesture(selectableTextStart + const Offset(50.0, 5.0));
+          await tester.startGesture(textOffsetToPosition(tester, 18));
       await tester.pump(const Duration(milliseconds: 500));
 
       final EditableText editableTextWidget = tester.widget(find.byType(EditableText).first);
@@ -3397,36 +3471,52 @@ void main() {
       expect(
         controller.selection,
         const TextSelection(
-          baseOffset: 0,
-          extentOffset: 7,
+          baseOffset: 13,
+          extentOffset: 23,
         ),
       );
-      // Cursor move doesn't trigger a toolbar initially.
+      // Word select doesn't trigger a toolbar initially.
       expect(find.byType(CupertinoButton), findsNothing);
 
       await gesture.moveBy(const Offset(100, 0));
       await tester.pump();
 
-      // The selection position is now moved with the drag.
+      // The selection is now moved with the drag.
       expect(
         controller.selection,
         const TextSelection(
-          baseOffset: 0,
-          extentOffset: 12,
+          baseOffset: 13,
+          extentOffset: 35,
         ),
       );
       // Still no toolbar.
       expect(find.byType(CupertinoButton), findsNothing);
 
-      await gesture.moveBy(const Offset(100, 0));
+      // The selection is moved with a backwards drag.
+      await gesture.moveBy(const Offset(-200, 0));
       await tester.pump();
 
-      // The selection position is now moved with the drag.
+      // The selection is now moved with the drag.
       expect(
         controller.selection,
         const TextSelection(
-          baseOffset: 0,
-          extentOffset: 23,
+          baseOffset: 23,
+          extentOffset: 8,
+        ),
+      );
+      // Still no toolbar.
+      expect(find.byType(CupertinoButton), findsNothing);
+
+      // The selection is moved with a backwards drag.
+      await gesture.moveBy(const Offset(-100, 0));
+      await tester.pump();
+
+      // The selection is now moved with the drag.
+      expect(
+        controller.selection,
+        const TextSelection(
+          baseOffset: 23,
+          extentOffset: 0,
         ),
       );
       // Still no toolbar.
@@ -3439,8 +3529,8 @@ void main() {
       expect(
         controller.selection,
         const TextSelection(
-          baseOffset: 0,
-          extentOffset: 23,
+          baseOffset: 23,
+          extentOffset: 0,
         ),
       );
       // The toolbar now shows up.