Fix stack filtering (#49956)

packages/flutter/lib/src/foundation/assertions.dart

@@ -126,7 +126,7 @@ class RepetitiveStackFrameFilter extends StackFilter {
 
   @override
   void filter(List<StackFrame> stackFrames, List<String> reasons) {
-    for (int index = 0; index < stackFrames.length; index += 1) {
+    for (int index = 0; index < stackFrames.length - numFrames; index += 1) {
       if (_matchesFrames(stackFrames.skip(index).take(numFrames).toList())) {
         reasons.setRange(index, index + numFrames, _replacements);
         index += numFrames - 1;
@@ -135,6 +135,9 @@ class RepetitiveStackFrameFilter extends StackFilter {
   }
 
   bool _matchesFrames(List<StackFrame> stackFrames) {
+    if (stackFrames.length < numFrames) {
+      return false;
+    }
     for (int index = 0; index < stackFrames.length; index++) {
       if (!frames[index].matches(stackFrames[index])) {
         return false;

packages/flutter/test/foundation/assertions_test.dart

@@ -428,4 +428,24 @@ void main() {
     expect(trace, isNotNull);
     expect(trace.value, stack);
   });
+
+  test('RepetitiveStackFrameFilter does not go out of range', () {
+    const RepetitiveStackFrameFilter filter = RepetitiveStackFrameFilter(
+      frames: <PartialStackFrame>[
+        PartialStackFrame(className: 'TestClass', method: 'test1', package: 'package:test/blah.dart'),
+        PartialStackFrame(className: 'TestClass', method: 'test2', package: 'package:test/blah.dart'),
+        PartialStackFrame(className: 'TestClass', method: 'test3', package: 'package:test/blah.dart'),
+      ],
+      replacement: 'test',
+    );
+    final List<String> reasons = List<String>(2);
+    filter.filter(
+      const <StackFrame>[
+        StackFrame(className: 'TestClass', method: 'test1', packageScheme: 'package', package: 'test', packagePath: 'blah.dart', line: 1, column: 1, number: 0, source: ''),
+        StackFrame(className: 'TestClass', method: 'test2', packageScheme: 'package', package: 'test', packagePath: 'blah.dart', line: 1, column: 1, number: 0, source: ''),
+      ],
+      reasons,
+    );
+    expect(reasons, List<String>(2));
+  });
 }