Avoid using `TextAffinity` in `TextBoundary` (#117446)

* Avoid affinity like the plague

* ignore lint

* clean up

* fix test

* review

* Move wordboundary to text painter

* docs

* fix tests

packages/flutter/lib/src/painting/text_painter.dart

@@ -144,6 +144,133 @@ enum TextWidthBasis {
   longestLine,
 }
 
+/// A [TextBoundary] subclass for locating word breaks.
+///
+/// The underlying implementation uses [UAX #29](https://unicode.org/reports/tr29/)
+/// defined default word boundaries.
+///
+/// The default word break rules can be tailored to meet the requirements of
+/// different use cases. For instance, the default rule set keeps horizontal
+/// whitespaces together as a single word, which may not make sense in a
+/// word-counting context -- "hello    world" counts as 3 words instead of 2.
+/// An example is the [moveByWordBoundary] variant, which is a tailored
+/// word-break locator that more closely matches the default behavior of most
+/// platforms and editors when it comes to handling text editing keyboard
+/// shortcuts that move or delete word by word.
+class WordBoundary extends TextBoundary {
+  /// Creates a [WordBoundary] with the text and layout information.
+  WordBoundary._(this._text, this._paragraph);
+
+  final InlineSpan _text;
+  final ui.Paragraph _paragraph;
+
+  @override
+  TextRange getTextBoundaryAt(int position) => _paragraph.getWordBoundary(TextPosition(offset: max(position, 0)));
+
+  // Combines two UTF-16 code units (high surrogate + low surrogate) into a
+  // single code point that represents a supplementary character.
+  static int _codePointFromSurrogates(int highSurrogate, int lowSurrogate) {
+    assert(
+      TextPainter._isHighSurrogate(highSurrogate),
+      'U+${highSurrogate.toRadixString(16).toUpperCase().padLeft(4, "0")}) is not a high surrogate.',
+    );
+    assert(
+      TextPainter._isLowSurrogate(lowSurrogate),
+      'U+${lowSurrogate.toRadixString(16).toUpperCase().padLeft(4, "0")}) is not a low surrogate.',
+    );
+    const int base = 0x010000 - (0xD800 << 10) - 0xDC00;
+    return (highSurrogate << 10) + lowSurrogate + base;
+  }
+
+  // The Runes class does not provide random access with a code unit offset.
+  int? _codePointAt(int index) {
+    final int? codeUnitAtIndex = _text.codeUnitAt(index);
+    if (codeUnitAtIndex == null) {
+      return null;
+    }
+    switch (codeUnitAtIndex & 0xFC00) {
+      case 0xD800:
+        return _codePointFromSurrogates(codeUnitAtIndex, _text.codeUnitAt(index + 1)!);
+      case 0xDC00:
+        return _codePointFromSurrogates(_text.codeUnitAt(index - 1)!, codeUnitAtIndex);
+      default:
+        return codeUnitAtIndex;
+    }
+  }
+
+  static bool _isNewline(int codePoint) {
+    switch (codePoint) {
+      case 0x000A:
+      case 0x0085:
+      case 0x000B:
+      case 0x000C:
+      case 0x2028:
+      case 0x2029:
+        return true;
+      default:
+        return false;
+    }
+  }
+
+  bool _skipSpacesAndPunctuations(int offset, bool forward) {
+    // Use code point since some punctuations are supplementary characters.
+    // "inner" here refers to the code unit that's before the break in the
+    // search direction (`forward`).
+    final int? innerCodePoint = _codePointAt(forward ? offset - 1 : offset);
+    final int? outerCodeUnit = _text.codeUnitAt(forward ? offset : offset - 1);
+
+    // Make sure the hard break rules in UAX#29 take precedence over the ones we
+    // add below. Luckily there're only 4 hard break rules for word breaks, and
+    // dictionary based breaking does not introduce new hard breaks:
+    // https://unicode-org.github.io/icu/userguide/boundaryanalysis/break-rules.html#word-dictionaries
+    //
+    // WB1 & WB2: always break at the start or the end of the text.
+    final bool hardBreakRulesApply = innerCodePoint == null || outerCodeUnit == null
+    // WB3a & WB3b: always break before and after newlines.
+                                  || _isNewline(innerCodePoint) || _isNewline(outerCodeUnit);
+    return hardBreakRulesApply || !RegExp(r'[\p{Space_Separator}\p{Punctuation}]', unicode: true).hasMatch(String.fromCharCode(innerCodePoint));
+  }
+
+  /// Returns a [TextBoundary] suitable for handling keyboard navigation
+  /// commands that change the current selection word by word.
+  ///
+  /// This [TextBoundary] is used by text widgets in the flutter framework to
+  /// provide default implementation for text editing shortcuts, for example,
+  /// "delete to the previous word".
+  ///
+  /// The implementation applies the same set of rules [WordBoundary] uses,
+  /// except that word breaks end on a space separator or a punctuation will be
+  /// skipped, to match the behavior of most platforms. Additional rules may be
+  /// added in the future to better match platform behaviors.
+  late final TextBoundary moveByWordBoundary = _UntilTextBoundary(this, _skipSpacesAndPunctuations);
+}
+
+class _UntilTextBoundary extends TextBoundary {
+  const _UntilTextBoundary(this._textBoundary, this._predicate);
+
+  final UntilPredicate _predicate;
+  final TextBoundary _textBoundary;
+
+  @override
+  int? getLeadingTextBoundaryAt(int position) {
+    if (position < 0) {
+      return null;
+    }
+    final int? offset = _textBoundary.getLeadingTextBoundaryAt(position);
+    return offset == null || _predicate(offset, false)
+      ? offset
+      : getLeadingTextBoundaryAt(offset - 1);
+  }
+
+  @override
+  int? getTrailingTextBoundaryAt(int position) {
+    final int? offset = _textBoundary.getTrailingTextBoundaryAt(max(position, 0));
+    return offset == null || _predicate(offset, true)
+      ? offset
+      : getTrailingTextBoundaryAt(offset);
+  }
+}
+
 /// This is used to cache and pass the computed metrics regarding the
 /// caret's size and position. This is preferred due to the expensive
 /// nature of the calculation.
@@ -750,7 +877,7 @@ class TextPainter {
 
   // Creates a ui.Paragraph using the current configurations in this class and
   // assign it to _paragraph.
-  void _createParagraph() {
+  ui.Paragraph _createParagraph() {
     assert(_paragraph == null || _rebuildParagraphForPaint);
     final InlineSpan? text = this.text;
     if (text == null) {
@@ -763,8 +890,9 @@ class TextPainter {
       _debugMarkNeedsLayoutCallStack = null;
       return true;
     }());
-    _paragraph = builder.build();
+    final ui.Paragraph paragraph = _paragraph = builder.build();
     _rebuildParagraphForPaint = false;
+    return paragraph;
   }
 
   void _layoutParagraph(double minWidth, double maxWidth) {
@@ -861,13 +989,18 @@ class TextPainter {
     canvas.drawParagraph(_paragraph!, offset);
   }
 
-  // Returns true iff the given value is a valid UTF-16 surrogate. The value
+  // Returns true iff the given value is a valid UTF-16 high surrogate. The value
   // must be a UTF-16 code unit, meaning it must be in the range 0x0000-0xFFFF.
   //
   // See also:
   //   * https://en.wikipedia.org/wiki/UTF-16#Code_points_from_U+010000_to_U+10FFFF
-  static bool _isUtf16Surrogate(int value) {
-    return value & 0xF800 == 0xD800;
+  static bool _isHighSurrogate(int value) {
+    return value & 0xFC00 == 0xD800;
+  }
+
+  // Whether the given UTF-16 code unit is a low (second) surrogate.
+  static bool _isLowSurrogate(int value) {
+    return value & 0xFC00 == 0xDC00;
   }
 
   // Checks if the glyph is either [Unicode.RLM] or [Unicode.LRM]. These values take
@@ -886,7 +1019,7 @@ class TextPainter {
       return null;
     }
     // TODO(goderbauer): doesn't handle extended grapheme clusters with more than one Unicode scalar value (https://github.com/flutter/flutter/issues/13404).
-    return _isUtf16Surrogate(nextCodeUnit) ? offset + 2 : offset + 1;
+    return _isHighSurrogate(nextCodeUnit) ? offset + 2 : offset + 1;
   }
 
   /// Returns the closest offset before `offset` at which the input cursor can
@@ -897,7 +1030,7 @@ class TextPainter {
       return null;
     }
     // TODO(goderbauer): doesn't handle extended grapheme clusters with more than one Unicode scalar value (https://github.com/flutter/flutter/issues/13404).
-    return _isUtf16Surrogate(prevCodeUnit) ? offset - 2 : offset - 1;
+    return _isLowSurrogate(prevCodeUnit) ? offset - 2 : offset - 1;
   }
 
   // Unicode value for a zero width joiner character.
@@ -916,7 +1049,7 @@ class TextPainter {
     const int NEWLINE_CODE_UNIT = 10;
 
     // Check for multi-code-unit glyphs such as emojis or zero width joiner.
-    final bool needsSearch = _isUtf16Surrogate(prevCodeUnit) || _text!.codeUnitAt(offset) == _zwjUtf16 || _isUnicodeDirectionality(prevCodeUnit);
+    final bool needsSearch = _isHighSurrogate(prevCodeUnit) || _isLowSurrogate(prevCodeUnit) || _text!.codeUnitAt(offset) == _zwjUtf16 || _isUnicodeDirectionality(prevCodeUnit);
     int graphemeClusterLength = needsSearch ? 2 : 1;
     List<TextBox> boxes = <TextBox>[];
     while (boxes.isEmpty) {
@@ -966,7 +1099,7 @@ class TextPainter {
     final int nextCodeUnit = plainText.codeUnitAt(min(offset, plainTextLength - 1));
 
     // Check for multi-code-unit glyphs such as emojis or zero width joiner
-    final bool needsSearch = _isUtf16Surrogate(nextCodeUnit) || nextCodeUnit == _zwjUtf16 || _isUnicodeDirectionality(nextCodeUnit);
+    final bool needsSearch = _isHighSurrogate(nextCodeUnit) || _isLowSurrogate(nextCodeUnit) || nextCodeUnit == _zwjUtf16 || _isUnicodeDirectionality(nextCodeUnit);
     int graphemeClusterLength = needsSearch ? 2 : 1;
     List<TextBox> boxes = <TextBox>[];
     while (boxes.isEmpty) {
@@ -1141,6 +1274,18 @@ class TextPainter {
     return _paragraph!.getWordBoundary(position);
   }
 
+  /// {@template flutter.painting.TextPainter.wordBoundaries}
+  /// Returns a [TextBoundary] that can be used to perform word boundary analysis
+  /// on the current [text].
+  ///
+  /// This [TextBoundary] uses word boundary rules defined in [Unicode Standard
+  /// Annex #29](http://www.unicode.org/reports/tr29/#Word_Boundaries).
+  /// {@endtemplate}
+  ///
+  /// Currently word boundary analysis can only be performed after [layout]
+  /// has been called.
+  WordBoundary get wordBoundaries => WordBoundary._(text!, _paragraph!);
+
   /// Returns the text range of the line at the given offset.
   ///
   /// The newline (if any) is not returned as part of the range.

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

@@ -2098,6 +2098,9 @@ class RenderEditable extends RenderBox with RelayoutWhenSystemFontsChangeMixin,
     _setSelection(newSelection, cause);
   }
 
+  /// {@macro flutter.painting.TextPainter.wordBoundaries}
+  WordBoundary get wordBoundaries => _textPainter.wordBoundaries;
+
   /// Select a word around the location of the last tap down.
   ///
   /// {@macro flutter.rendering.RenderEditable.selectPosition}

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

@@ -1559,21 +1559,21 @@ class _SelectableFragment with Selectable, ChangeNotifier implements TextLayoutM
     switch (granularity) {
       case TextGranularity.character:
         final String text = range.textInside(fullText);
-        newPosition = _getNextPosition(CharacterBoundary(text), targetedEdge, forward);
+        newPosition = _moveBeyondTextBoundaryAtDirection(targetedEdge, forward, CharacterBoundary(text));
         result = SelectionResult.end;
         break;
       case TextGranularity.word:
-        final String text = range.textInside(fullText);
-        newPosition = _getNextPosition(WhitespaceBoundary(text) + WordBoundary(this), targetedEdge, forward);
+        final TextBoundary textBoundary = paragraph._textPainter.wordBoundaries.moveByWordBoundary;
+        newPosition = _moveBeyondTextBoundaryAtDirection(targetedEdge, forward, textBoundary);
         result = SelectionResult.end;
         break;
       case TextGranularity.line:
-        newPosition = _getNextPosition(LineBreak(this), targetedEdge, forward);
+        newPosition = _moveToTextBoundaryAtDirection(targetedEdge, forward, LineBoundary(this));
         result = SelectionResult.end;
         break;
       case TextGranularity.document:
         final String text = range.textInside(fullText);
-        newPosition = _getNextPosition(DocumentBoundary(text), targetedEdge, forward);
+        newPosition = _moveBeyondTextBoundaryAtDirection(targetedEdge, forward, DocumentBoundary(text));
         if (forward && newPosition.offset == range.end) {
           result = SelectionResult.next;
         } else if (!forward && newPosition.offset == range.start) {
@@ -1592,15 +1592,43 @@ class _SelectableFragment with Selectable, ChangeNotifier implements TextLayoutM
     return result;
   }
 
-  TextPosition _getNextPosition(TextBoundary boundary, TextPosition position, bool forward) {
-    if (forward) {
-      return _clampTextPosition(
-        (PushTextPosition.forward + boundary).getTrailingTextBoundaryAt(position)
-      );
+  // Move **beyond** the local boundary of the given type (unless range.start or
+  // range.end is reached). Used for most TextGranularity types except for
+  // TextGranularity.line, to ensure the selection movement doesn't get stuck at
+  // a local fixed point.
+  TextPosition _moveBeyondTextBoundaryAtDirection(TextPosition end, bool forward, TextBoundary textBoundary) {
+    final int newOffset = forward
+      ? textBoundary.getTrailingTextBoundaryAt(end.offset) ?? range.end
+      : textBoundary.getLeadingTextBoundaryAt(end.offset - 1) ?? range.start;
+    return TextPosition(offset: newOffset);
+  }
+
+  // Move **to** the local boundary of the given type. Typically used for line
+  // boundaries, such that performing "move to line start" more than once never
+  // moves the selection to the previous line.
+  TextPosition _moveToTextBoundaryAtDirection(TextPosition end, bool forward, TextBoundary textBoundary) {
+    assert(end.offset >= 0);
+    final int caretOffset;
+    switch (end.affinity) {
+      case TextAffinity.upstream:
+        if (end.offset < 1 && !forward) {
+          assert (end.offset == 0);
+          return const TextPosition(offset: 0);
+        }
+        final CharacterBoundary characterBoundary = CharacterBoundary(fullText);
+        caretOffset = math.max(
+          0,
+          characterBoundary.getLeadingTextBoundaryAt(range.start + end.offset) ?? range.start,
+        ) - 1;
+        break;
+      case TextAffinity.downstream:
+        caretOffset = end.offset;
+        break;
     }
-    return _clampTextPosition(
-      (PushTextPosition.backward + boundary).getLeadingTextBoundaryAt(position),
-    );
+    final int offset = forward
+      ? textBoundary.getTrailingTextBoundaryAt(caretOffset) ?? range.end
+      : textBoundary.getLeadingTextBoundaryAt(caretOffset) ?? range.start;
+    return TextPosition(offset: offset);
   }
 
   MapEntry<TextPosition, SelectionResult> _handleVerticalMovement(TextPosition position, {required double horizontalBaselineInParagraphCoordinates, required bool below}) {

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

@@ -137,11 +137,11 @@ class ExtendSelectionToNextWordBoundaryIntent extends DirectionalCaretMovementIn
 /// reverse.
 ///
 /// This is typically only used on MacOS.
-class ExtendSelectionToNextWordBoundaryOrCaretLocationIntent extends DirectionalTextEditingIntent {
+class ExtendSelectionToNextWordBoundaryOrCaretLocationIntent extends DirectionalCaretMovementIntent {
   /// Creates an [ExtendSelectionToNextWordBoundaryOrCaretLocationIntent].
   const ExtendSelectionToNextWordBoundaryOrCaretLocationIntent({
     required bool forward,
-  }) : super(forward);
+  }) : super(forward, false, true);
 }
 
 /// Expands the current selection to the document boundary in the direction
@@ -154,11 +154,11 @@ class ExtendSelectionToNextWordBoundaryOrCaretLocationIntent extends Directional
 ///
 ///   [ExtendSelectionToDocumentBoundaryIntent], which is similar but always
 ///   moves the extent.
-class ExpandSelectionToDocumentBoundaryIntent extends DirectionalTextEditingIntent {
+class ExpandSelectionToDocumentBoundaryIntent extends DirectionalCaretMovementIntent {
   /// Creates an [ExpandSelectionToDocumentBoundaryIntent].
   const ExpandSelectionToDocumentBoundaryIntent({
     required bool forward,
-  }) : super(forward);
+  }) : super(forward, false);
 }
 
 /// Expands the current selection to the closest line break in the direction
@@ -173,11 +173,11 @@ class ExpandSelectionToDocumentBoundaryIntent extends DirectionalTextEditingInte
 ///
 ///   [ExtendSelectionToLineBreakIntent], which is similar but always moves the
 ///   extent.
-class ExpandSelectionToLineBreakIntent extends DirectionalTextEditingIntent {
+class ExpandSelectionToLineBreakIntent extends DirectionalCaretMovementIntent {
   /// Creates an [ExpandSelectionToLineBreakIntent].
   const ExpandSelectionToLineBreakIntent({
     required bool forward,
-  }) : super(forward);
+  }) : super(forward, false);
 }
 
 /// Extends, or moves the current selection from the current

packages/flutter/test/material/text_field_test.dart

@@ -9785,7 +9785,8 @@ void main() {
     await tester.pumpAndSettle();
     expect(
       controller.selection,
-      const TextSelection.collapsed(offset: 56, affinity: TextAffinity.upstream),
+      // arrowRight always sets the affinity to downstream.
+      const TextSelection.collapsed(offset: 56),
     );
 
     // Keep moving out.
@@ -9795,7 +9796,7 @@ void main() {
     await tester.pumpAndSettle();
     expect(
       controller.selection,
-      const TextSelection.collapsed(offset: 62, affinity: TextAffinity.upstream),
+      const TextSelection.collapsed(offset: 62),
     );
     for (int i = 0; i < (66 - 62); i += 1) {
       await tester.sendKeyEvent(LogicalKeyboardKey.arrowRight);
@@ -9803,7 +9804,7 @@ void main() {
     await tester.pumpAndSettle();
     expect(
       controller.selection,
-      const TextSelection.collapsed(offset: 66, affinity: TextAffinity.upstream),
+      const TextSelection.collapsed(offset: 66),
     ); // We're at the edge now.
 
     await tester.pumpAndSettle();

packages/flutter/test/rendering/paragraph_test.dart

@@ -1075,8 +1075,13 @@ void main() {
         ),
       );
       selection = paragraph.selections[0];
-      expect(selection.start, 0); // [how ]are you
-      expect(selection.end, 4);
+      if (isBrowser && !isCanvasKit) {
+        // how [are you\n]
+        expect(selection, const TextRange(start: 4, end: 12));
+      } else {
+        // [how ]are you
+        expect(selection, const TextRange(start: 0, end: 4));
+      }
     });
 
     test('can granularly extend selection - document', () async {

packages/flutter/test/widgets/default_text_editing_shortcuts_test.dart

@@ -45,7 +45,7 @@ void main() {
     );
   }
 
-  group('iOS: do not delete/backspace events', () {
+  group('iOS: do not handle delete/backspace events', () {
     final TargetPlatformVariant iOS = TargetPlatformVariant.only(TargetPlatform.iOS);
     final FocusNode editable = FocusNode();
     final FocusNode spy = FocusNode();

packages/flutter/test/widgets/editable_text_shortcuts_test.dart

@@ -576,12 +576,12 @@ void main() {
             'Now is the time for\n'
             'all good people\n'
             'to come to the aid\n'
-            'of their country',
+            'of their ',
           );
 
           expect(
             controller.selection,
-            const TextSelection.collapsed(offset: 71),
+            const TextSelection.collapsed(offset: 64),
           );
         }, variant: TargetPlatformVariant.all(excluding: <TargetPlatform>{ TargetPlatform.iOS }));
 
@@ -795,7 +795,7 @@ void main() {
 
         testWidgets('softwrap line boundary, upstream', (WidgetTester tester) async {
           controller.text = testSoftwrapText;
-          // Place the caret at the beginning of the 3rd line.
+          // Place the caret at the end of the 2nd line.
           controller.selection = const TextSelection.collapsed(
             offset: 40,
             affinity: TextAffinity.upstream,
@@ -827,12 +827,11 @@ void main() {
           await tester.pumpWidget(buildEditableText());
           await sendKeyCombination(tester, lineModifierBackspace());
 
-          expect(controller.text, testSoftwrapText);
-
           expect(
             controller.selection,
             const TextSelection.collapsed(offset: 40),
           );
+          expect(controller.text, testSoftwrapText);
         }, variant: TargetPlatformVariant.all());
 
         testWidgets('readonly', (WidgetTester tester) async {
@@ -976,7 +975,7 @@ void main() {
 
         testWidgets('softwrap line boundary, upstream', (WidgetTester tester) async {
           controller.text = testSoftwrapText;
-          // Place the caret at the beginning of the 3rd line.
+          // Place the caret at the end of the 2nd line.
           controller.selection = const TextSelection.collapsed(
             offset: 40,
             affinity: TextAffinity.upstream,
@@ -1215,7 +1214,6 @@ void main() {
 
             expect(controller.selection, const TextSelection.collapsed(
               offset: 21,
-              affinity: TextAffinity.upstream,
             ));
           }, variant: TargetPlatformVariant.all());
 
@@ -1230,7 +1228,6 @@ void main() {
 
             expect(controller.selection, const TextSelection.collapsed(
               offset: 10,
-              affinity: TextAffinity.upstream,
             ));
           }, variant: allExceptApple);
 
@@ -1341,7 +1338,6 @@ void main() {
             await tester.pump();
             expect(controller.selection, const TextSelection.collapsed(
               offset: 46, // After "to".
-              affinity: TextAffinity.upstream,
             ));
 
             // "good" to "come" is selected.
@@ -1354,7 +1350,6 @@ void main() {
             await tester.pump();
             expect(controller.selection, const TextSelection.collapsed(
               offset: 28, // After "good".
-              affinity: TextAffinity.upstream,
             ));
           }, variant: allExceptApple);
 
@@ -1718,8 +1713,7 @@ void main() {
       await tester.pump();
 
       expect(controller.selection, const TextSelection.collapsed(
-        offset: 10,
-        affinity: TextAffinity.upstream,
+        offset: 10, // after the first "the"
       ));
     }, variant: macOSOnly);
 
@@ -1790,7 +1784,6 @@ void main() {
       await tester.pump();
       expect(controller.selection, const TextSelection.collapsed(
         offset: 46, // After "to".
-        affinity: TextAffinity.upstream,
       ));
 
       // "good" to "come" is selected.
@@ -1803,7 +1796,6 @@ void main() {
       await tester.pump();
       expect(controller.selection, const TextSelection.collapsed(
         offset: 28, // After "good".
-        affinity: TextAffinity.upstream,
       ));
     }, variant: macOSOnly);
 
@@ -2351,9 +2343,7 @@ void main() {
       expect(controller.text, 'testing');
       expect(
         controller.selection,
-        const TextSelection.collapsed(
-            offset: 6,
-            affinity: TextAffinity.upstream), // should not expand selection
+        const TextSelection.collapsed(offset: 6), // should not expand selection
         reason: selectRight.toString(),
       );
     }, variant: TargetPlatformVariant.desktop());

packages/flutter/test/widgets/editable_text_test.dart

@@ -5695,7 +5695,6 @@ void main() {
         const TextSelection(
           baseOffset: 0,
           extentOffset: 6,
-          affinity: TextAffinity.upstream,
         ),
       ),
       reason: 'on $platform',
@@ -5957,7 +5956,6 @@ void main() {
       equals(
         const TextSelection.collapsed(
           offset: testText.length,
-          affinity: TextAffinity.upstream,
         ),
       ),
       reason: 'on $platform',
@@ -6001,7 +5999,6 @@ void main() {
       equals(
         const TextSelection.collapsed(
           offset: 3,
-          affinity: TextAffinity.upstream,
         ),
       ),
       reason: 'on $platform',
@@ -6193,7 +6190,6 @@ void main() {
         const TextSelection(
           baseOffset: 10,
           extentOffset: 10,
-          affinity: TextAffinity.upstream,
         ),
       ),
       reason: 'on $platform',
@@ -6653,7 +6649,6 @@ void main() {
       equals(
         const TextSelection.collapsed(
           offset: 23,
-          affinity: TextAffinity.upstream,
         ),
       ),
       reason: 'on $platform',
@@ -6678,7 +6673,6 @@ void main() {
           equals(
             const TextSelection.collapsed(
               offset: 23,
-              affinity: TextAffinity.upstream,
             ),
           ),
           reason: 'on $platform',
@@ -6721,7 +6715,6 @@ void main() {
           equals(
             const TextSelection.collapsed(
               offset: 23,
-              affinity: TextAffinity.upstream,
             ),
           ),
           reason: 'on $platform',
@@ -6807,7 +6800,6 @@ void main() {
       equals(
         const TextSelection.collapsed(
           offset: 32,
-          affinity: TextAffinity.upstream,
         ),
       ),
       reason: 'on $platform',
@@ -6832,7 +6824,6 @@ void main() {
           equals(
             const TextSelection.collapsed(
               offset: 32,
-              affinity: TextAffinity.upstream,
             ),
           ),
           reason: 'on $platform',
@@ -6875,7 +6866,6 @@ void main() {
           equals(
             const TextSelection.collapsed(
               offset: 32,
-              affinity: TextAffinity.upstream,
             ),
           ),
           reason: 'on $platform',
@@ -6971,7 +6961,6 @@ void main() {
       equals(
         const TextSelection.collapsed(
           offset: 32,
-          affinity: TextAffinity.upstream,
         ),
       ),
       reason: 'on $platform',
@@ -6996,7 +6985,6 @@ void main() {
           equals(
             const TextSelection.collapsed(
               offset: 32,
-              affinity: TextAffinity.upstream,
             ),
           ),
           reason: 'on $platform',
@@ -7039,7 +7027,6 @@ void main() {
           equals(
             const TextSelection.collapsed(
               offset: 32,
-              affinity: TextAffinity.upstream,
             ),
           ),
           reason: 'on $platform',
@@ -7136,7 +7123,6 @@ void main() {
       equals(
         const TextSelection.collapsed(
           offset: 23,
-          affinity: TextAffinity.upstream,
         ),
       ),
       reason: 'on $platform',
@@ -7182,7 +7168,6 @@ void main() {
             const TextSelection(
               baseOffset: 23,
               extentOffset: 23,
-              affinity: TextAffinity.upstream,
             ),
           ),
           reason: 'on $platform',
@@ -7193,7 +7178,6 @@ void main() {
             const TextSelection(
               baseOffset: 23,
               extentOffset: 23,
-              affinity: TextAffinity.upstream,
             ),
           ),
           reason: 'on $platform',
@@ -7327,7 +7311,6 @@ void main() {
       controller.selection,
       equals(const TextSelection.collapsed(
         offset: 4,
-        affinity: TextAffinity.upstream,
       )),
     );
 
@@ -7511,7 +7494,6 @@ void main() {
       equals(
         const TextSelection.collapsed(
           offset: 32,
-          affinity: TextAffinity.upstream,
         ),
       ),
       reason: 'on $platform',
@@ -7535,7 +7517,6 @@ void main() {
           equals(
             const TextSelection.collapsed(
               offset: 32,
-              affinity: TextAffinity.upstream,
             ),
           ),
           reason: 'on $platform',
@@ -7593,7 +7574,6 @@ void main() {
           equals(
             const TextSelection.collapsed(
               offset: 32,
-              affinity: TextAffinity.upstream,
             ),
           ),
           reason: 'on $platform',
@@ -7706,7 +7686,6 @@ void main() {
       equals(
         const TextSelection.collapsed(
           offset: 32,
-          affinity: TextAffinity.upstream,
         ),
       ),
       reason: 'on $platform',
@@ -7730,7 +7709,6 @@ void main() {
           equals(
             const TextSelection.collapsed(
               offset: 32,
-              affinity: TextAffinity.upstream,
             ),
           ),
           reason: 'on $platform',
@@ -7788,7 +7766,6 @@ void main() {
           equals(
             const TextSelection.collapsed(
               offset: 32,
-              affinity: TextAffinity.upstream,
             ),
           ),
           reason: 'on $platform',
@@ -7900,7 +7877,6 @@ void main() {
       equals(
         const TextSelection.collapsed(
           offset: 32,
-          affinity: TextAffinity.upstream,
         ),
       ),
     );
@@ -7994,7 +7970,6 @@ void main() {
       controller.selection,
       equals(const TextSelection.collapsed(
         offset: testText.length,
-        affinity: TextAffinity.upstream,
       )),
     );
 
@@ -8078,7 +8053,6 @@ void main() {
       controller.selection,
       equals(const TextSelection.collapsed(
         offset: testText.length,
-        affinity: TextAffinity.upstream,
       )),
     );
 
@@ -11036,7 +11010,6 @@ void main() {
     controller.selection = const TextSelection(
       baseOffset: 15,
       extentOffset: 15,
-      affinity: TextAffinity.upstream,
     );
     await tester.pump();
     expect(controller.selection.isCollapsed, true);
@@ -11275,7 +11248,6 @@ void main() {
         const TextSelection(
           baseOffset: 29,
           extentOffset: 0,
-          affinity: TextAffinity.upstream,
         ),
       ),
     );

packages/flutter/test/widgets/selectable_region_test.dart

@@ -1296,12 +1296,12 @@ void main() {
 
       await sendKeyCombination(tester, SingleActivator(LogicalKeyboardKey.arrowLeft, shift: true, alt: alt, control: control));
       await tester.pump();
-      // Ho[w are you]?
+      // Ho[w are ]you?
       // Good, and you?
       // Fine, thank you.
       expect(paragraph1.selections.length, 1);
       expect(paragraph1.selections[0].start, 2);
-      expect(paragraph1.selections[0].end, 11);
+      expect(paragraph1.selections[0].end, 8);
       expect(paragraph2.selections.length, 0);
     }, variant: TargetPlatformVariant.all());