fix null safe check in RenderIndexedStack (#107581)

engine-flutter-autoroll · Jul 13, 2022 · b26346f · b26346f
1 parent d949ca4
commit b26346f
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Showing 2 changed files with 29 additions and 1 deletion.
diff --git a/packages/flutter/lib/src/rendering/stack.dart b/packages/flutter/lib/src/rendering/stack.dart
@@ -790,7 +790,7 @@ class RenderIndexedStack extends RenderStack {
  while (child != null) {
  children.add(child.toDiagnosticsNode(
  name: 'child ${i + 1}',
- style: i != index! ? DiagnosticsTreeStyle.offstage : null,
+ style: i != index ? DiagnosticsTreeStyle.offstage : null,
  ));
  child = (child.parentData! as StackParentData).nextSibling;
  i += 1;

diff --git a/packages/flutter/test/rendering/stack_test.dart b/packages/flutter/test/rendering/stack_test.dart
@@ -145,6 +145,34 @@ void main() {
  expect(diagnosticNodes[2].name, 'child 3');
  expect(diagnosticNodes[2].style, DiagnosticsTreeStyle.sparse);
  });
+
+ test('debugDescribeChildren handles a null index', () {
+ final RenderBox child1 = RenderConstrainedBox(
+ additionalConstraints: BoxConstraints.tight(const Size(100.0, 100.0)),
+ );
+ final RenderBox child2 = RenderConstrainedBox(
+ additionalConstraints: BoxConstraints.tight(const Size(100.0, 100.0)),
+ );
+ final RenderBox child3 = RenderConstrainedBox(
+ additionalConstraints: BoxConstraints.tight(const Size(100.0, 100.0)),
+ );
+
+ final RenderBox stack = RenderIndexedStack(
+ index: null,
+ children: <RenderBox>[child1, child2, child3],
+ );
+
+ final List<DiagnosticsNode> diagnosticNodes = stack.debugDescribeChildren();
+
+ expect(diagnosticNodes[0].name, 'child 1');
+ expect(diagnosticNodes[0].style, DiagnosticsTreeStyle.offstage);
+
+ expect(diagnosticNodes[1].name, 'child 2');
+ expect(diagnosticNodes[1].style, DiagnosticsTreeStyle.offstage);
+
+ expect(diagnosticNodes[2].name, 'child 3');
+ expect(diagnosticNodes[2].style, DiagnosticsTreeStyle.offstage);
+ });
  });
 
  test('Stack in Flex can layout with no children', () {