Hot restart prints errors in terminal

[nshahan]

Repro:
webdev: 2.0.0-alpha.4
build_web_compilers: 2.0.0-alpha.2
sdk: 2.3.0-dev.0.1
Spinning square example

Edit the color of the square, save, and trigger a hot restart in devtools. There is an error printed to the terminal where webdev is running:

ERROR - 2019-04-17 10:55:15.501865
Asynchronous error
NoSuchMethodError: The getter 'length' was called on null.
Receiver: null
Tried calling: length
dart:convert                                                               Codec.encode
package:dwds/src/chrome_proxy_service.dart 658:30                          ChromeProxyService._chromeConsoleStreamController.<fn>.<fn>
dart:async                                                                 _EventSinkWrapper.add
package:webkit_inspection_protocol/webkit_inspection_protocol.dart 302:22  WipDomain.eventStream.<fn>.<fn>

[nshahan]

I just noticed this does not happen when I run webdev with the --auto restart option.

[nshahan]

Also prints messages in the web consoles for the app and devtools.

App:

Uncaught (in promise) NoSuchMethodError: tried to call a non-function, such as null: 'method'

Devtools

main.dart.js:1116 Uncaught Unexpected error from chrome devtools:
text: Uncaught (in promise)
exception:
  description: null
  type: string
  value: NoSuchMethodError: tried to call a non-function, such as null: 'method'
attempted eval: `require("dart_sdk").developer.invokeExtension(
    "ext.flutter.inspector.getRootWidgetSummaryTree", JSON.stringify({"objectGroup":"temp_4"}));
`
 (-32603) from ext.flutter.inspector.getRootWidgetSummaryTree()
    at Object.wrapException (http://localhost:51877/main.dart.js:1116:17)
    at _rootHandleUncaughtError_closure.call$0 (http://localhost:51877/main.dart.js:19437:17)
    at Object._microtaskLoop (http://localhost:51877/main.dart.js:3750:21)
    at StaticClosure._startMicrotaskLoop (http://localhost:51877/main.dart.js:3756:11)
    at _AsyncRun__initializeScheduleImmediate_internalCallback.call$1 (http://localhost:51877/main.dart.js:17259:9)

[jakemac53]

Pretty sure this is fixed by #311, I can't repro it