flutter CI flakes: getStack: (-32603) getStack: NoSuchMethodError: The method 'toJson' was called on null. #1369
Description
We have seen flakes in flutter CI that seem due to dwds returning a null stack periodically.
00:41 +0 -1: test/web.shard/debugger_stepping_web_test.dart: Web debugger can step over statements [E]
getStack: (-32603) getStack: NoSuchMethodError: The method 'toJson' was called on null.
Receiver: null
Tried calling: toJson()
#0 Object.noSuchMethod (dart:core-patch/object_patch.dart:63:5)
#1 VmServerConnection._delegateRequest (package:vm_service/src/vm_service.dart:1602:28)
<asynchronous suspension>
package:vm_service/src/vm_service.dart 1626:45 new _OutstandingRequest
package:vm_service/src/vm_service.dart 2109:21 VmService._call
package:vm_service/src/vm_service.dart 1913:61 VmService.getStack
test/integration.shard/test_driver.dart 334:42 FlutterTestDriver.getTopStackFrame
===== asynchronous gap ===========================
test/integration.shard/test_driver.dart 343:25 FlutterTestDriver.getSourceLocation
===== asynchronous gap ===========================
test/web.shard/debugger_stepping_web_test.dart 40:39 main.<fn>
Related: Flutter issue: flutter/flutter#84012
https://ci.chromium.org/ui/p/flutter/builders/prod/Linux%20web_tool_tests/2947/overview
another failure on flutter hhh https://logs.chromium.org/logs/dart/buildbucket/cr-buildbucket.appspot.com/8840551373789240880/+/u/flutter_test_tool_tests/stdout