Flutter 3.0.3 Web开发调试遇Unexpected null value错误及跳转异常求助

我们近期基于Flutter 3.0.3（Dart 2.17.5 • DevTools 2.12.2）将现有Flutter应用转为Web版本，在Chrome中运行Web项目时触发如下错误：

Error: Unexpected null value.
    at Object.throw_ [as throw] (http://localhost:57060/dart_sdk.js:5080:11)
    at Object.nullCheck (http://localhost:57060/dart_sdk.js:5399:30)
    at auth_repo.AuthRepo._internal.loginUser (http://localhost:57060/packages/our_repo/modules/home/repository/our_db_search.lib.js:24349:77)
    at loginUser.next (<anonymous>)
    at http://localhost:57060/dart_sdk.js:40641:33
    at _RootZone.runUnary (http://localhost:57060/dart_sdk.js:40511:59)
    at _FutureListener.thenAwait.handleValue (http://localhost:57060/dart_sdk.js:35438:29)
    at handleValueCallback (http://localhost:57060/dart_sdk.js:35999:49)
    at _Future._propagateToListeners (http://localhost:57060/dart_sdk.js:36037:17)
    at [_complete] (http://localhost:57060/dart_sdk.js:35864:25)
    at _SyncCompleter.new.complete (http://localhost:57060/dart_sdk.js:35355:31)
    at onValue (http://localhost:57060/dart_sdk.js:35118:49)
    at _RootZone.runUnary (http://localhost:57060/dart_sdk.js:40511:59)
    at _FutureListener.then.handleValue (http://localhost:57060/dart_sdk.js:35438:29)
    at handleValueCallback (http://localhost:57060/dart_sdk.js:35999:49)
    at _Future._propagateToListeners (http://localhost:57060/dart_sdk.js:36037:17)
    at [_completeWithValue] (http://localhost:57060/dart_sdk.js:35872:23)
    at async._AsyncCallbackEntry.new.callback (http://localhost:57060/dart_sdk.js:35906:35)
    at Object._microtaskLoop (http://localhost:57060/dart_sdk.js:40778:13)
    at _startMicrotaskLoop (http://localhost:57060/dart_sdk.js:40784:13)
    at http://localhost:57060/dart_sdk.js:36261:9

点击错误信息跳转时浏览器显示"Internal Server Error"，调试难度极大。请问是否有开发者遇到过类似的Web项目问题？如需更多信息，请告知。

排查建议 #

• 定位AuthRepo._internal.loginUser方法的空值点：错误栈明确指向该方法编译后的JS代码第24349行77列，检查Flutter源码中对应位置是否存在强制解包（!）或未做空判断的变量，Web环境下部分移动端API/三方库的行为可能存在差异，导致变量为空。
• 绕开跳转异常直接调试：关闭DevTools自动跳转，直接查看编译后的our_db_search.lib.js对应行代码，或在Flutter源码的loginUser方法中添加日志，打印关键变量值确认空值来源。
• 切换编译模式验证：尝试执行flutter build web --release编译后运行，排查是否为debug模式下的编译异常。
• 清理缓存：执行flutter clean，同时清除Chrome浏览器缓存后重新运行项目，排除缓存导致的异常。

内容的提问来源于stack exchange，提问作者user3600064