Fixes semantics ordering when there are multiple TextFields with pref… (#148267)

�ix and suffix

fixes flutter/flutter#148248

Author: chunhtai

packages/flutter/lib/src/material/input_decorator.dart

@@ -1865,9 +1865,11 @@ class _InputDecoratorState extends State<InputDecorator> with TickerProviderStat
   late final CurvedAnimation _floatingLabelAnimation;
   late final AnimationController _shakingLabelController;
   final _InputBorderGap _borderGap = _InputBorderGap();
-  static const OrdinalSortKey _kPrefixSemanticsSortOrder = OrdinalSortKey(0);
-  static const OrdinalSortKey _kInputSemanticsSortOrder = OrdinalSortKey(1);
-  static const OrdinalSortKey _kSuffixSemanticsSortOrder = OrdinalSortKey(2);
+  // Provide a unique name to avoid mixing up sort order with sibling input
+  // decorators.
+  late final OrdinalSortKey _prefixSemanticsSortOrder = OrdinalSortKey(0, name: hashCode.toString());
+  late final OrdinalSortKey _inputSemanticsSortOrder = OrdinalSortKey(1, name: hashCode.toString());
+  late final OrdinalSortKey _suffixSemanticsSortOrder = OrdinalSortKey(2, name: hashCode.toString());
   static const SemanticsTag _kPrefixSemanticsTag = SemanticsTag('_InputDecoratorState.prefix');
   static const SemanticsTag _kSuffixSemanticsTag = SemanticsTag('_InputDecoratorState.suffix');
 
@@ -2219,7 +2221,7 @@ class _InputDecoratorState extends State<InputDecorator> with TickerProviderStat
           labelIsFloating: widget._labelShouldWithdraw,
           text: decoration.prefixText,
           style: MaterialStateProperty.resolveAs(decoration.prefixStyle, materialState) ?? hintStyle,
-          semanticsSortKey: needsSemanticsSortOrder ? _kPrefixSemanticsSortOrder : null,
+          semanticsSortKey: needsSemanticsSortOrder ? _prefixSemanticsSortOrder : null,
           semanticsTag: _kPrefixSemanticsTag,
           child: decoration.prefix,
         )
@@ -2230,15 +2232,15 @@ class _InputDecoratorState extends State<InputDecorator> with TickerProviderStat
           labelIsFloating: widget._labelShouldWithdraw,
           text: decoration.suffixText,
           style: MaterialStateProperty.resolveAs(decoration.suffixStyle, materialState) ?? hintStyle,
-          semanticsSortKey: needsSemanticsSortOrder ? _kSuffixSemanticsSortOrder : null,
+          semanticsSortKey: needsSemanticsSortOrder ? _suffixSemanticsSortOrder : null,
           semanticsTag: _kSuffixSemanticsTag,
           child: decoration.suffix,
         )
       : null;
 
     if (input != null && needsSemanticsSortOrder) {
       input = Semantics(
-        sortKey: _kInputSemanticsSortOrder,
+        sortKey: _inputSemanticsSortOrder,
         child: input,
       );
     }

packages/flutter/test/material/text_field_test.dart

@@ -1831,6 +1831,56 @@ void main() {
     expect(handle.opacity.value, equals(0.0));
   });
 
+  testWidgets('multiple text fields with prefix and suffix have correct semantics order.', (WidgetTester tester) async {
+    final TextEditingController controller1 = _textEditingController(
+      text: 'abc',
+    );
+    final TextEditingController controller2 = _textEditingController(
+      text: 'def',
+    );
+    await tester.pumpWidget(
+      MaterialApp(
+        home: Material(
+          child: Column(
+            children: <Widget>[
+              TextField(
+                decoration: const InputDecoration(
+                  prefixText: 'prefix1',
+                  suffixText: 'suffix1',
+                ),
+                enabled: false,
+                controller: controller1,
+              ),
+              TextField(
+                decoration: const InputDecoration(
+                  prefixText: 'prefix2',
+                  suffixText: 'suffix2',
+                ),
+                enabled: false,
+                controller: controller2,
+              ),
+            ],
+          ),
+        ),
+      ),
+    );
+    final List<String> orders = tester.semantics.simulatedAccessibilityTraversal(
+      startNode: find.semantics.byLabel('prefix1'),
+    ).map((SemanticsNode node) => node.label + node.value).toList();
+
+    expect(
+      orders,
+      <String>[
+        'prefix1',
+        'abc',
+        'suffix1',
+        'prefix2',
+        'def',
+        'suffix2',
+      ],
+    );
+  });
+
   testWidgets('selection handles are excluded from the semantics', (WidgetTester tester) async {
     final SemanticsTester semantics = SemanticsTester(tester);
     final TextEditingController controller = _textEditingController();