after upgrading to flutter 3.19.3 , I am getting the error below when I try to build and run on web.

[kimemia21]

Assertion failed: "boolean expression must not be null" Assertion failed: "boolean expression must not be null" at Object.wrapException (http://localhost:56086/dwds/src/injected/client.js:1036:17) at Object.assertThrow (http://localhost:56086/dwds/src/injected/client.js:1482:15) at Object.boolConversionCheck (http://localhost:56086/dwds/src/injected/client.js:1478:11) at http://localhost:56086/dwds/src/injected/client.js:24791:21 at _wrapJsFunctionForAsync_closure.$protected (http://localhost:56086/dwds/src/injected/client.js:3589:15) at _wrapJsFunctionForAsync_closure.call$2 (http://localhost:56086/dwds/src/injected/client.js:11698:12) at _awaitOnObject_closure.call$1 (http://localhost:56086/dwds/src/injected/client.js:11686:32) at StaticClosure._rootRunUnary (http://localhost:56086/dwds/src/injected/client.js:3948:18) at _CustomZone.runUnary$2$2 (http://localhost:56086/dwds/src/injected/client.js:13095:39) at _FuturepropagateToListeners_handleValueCallback.call$0 (http://localhost:56086/dwds/src/injected/client.js:12125:51) at Object._FuturepropagateToListeners (http://localhost:56086/dwds/src/injected/client.js:3731:93) at _Future._completeWithValue$1 (http://localhost:56086/dwds/src/injected/client.js:11956:9) at _AsyncAwaitCompleter.complete$1 (http://localhost:56086/dwds/src/injected/client.js:11672:14) at Object._asyncReturn (http://localhost:56086/dwds/src/injected/client.js:3561:17) at http://localhost:56086/dwds/src/injected/client.js:8926:24 at _wrapJsFunctionForAsync_closure.$protected (http://localhost:56086/dwds/src/injected/client.js:3589:15) at _wrapJsFunctionForAsync_closure.call$2 (http://localhost:56086/dwds/src/injected/client.js:11698:12) at _awaitOnObject_closure.call$1 (http://localhost:56086/dwds/src/injected/client.js:11686:32) at StaticClosure._rootRunUnary (http://localhost:56086/dwds/src/injected/client.js:3948:18) at _CustomZone.runUnary$2$2 (http://localhost:56086/dwds/src/injected/client.js:13095:39) at _FuturepropagateToListeners_handleValueCallback.call$0 (http://localhost:56086/dwds/src/injected/client.js:12125:51) at Object._FuturepropagateToListeners (http://localhost:56086/dwds/src/injected/client.js:3731:93) at _Future._completeWithValue$1 (http://localhost:56086/dwds/src/injected/client.js:11956:9) at _AsyncAwaitCompleter.complete$1 (http://localhost:56086/dwds/src/injected/client.js:11672:14) at Object._asyncReturn (http://localhost:56086/dwds/src/injected/client.js:3561:17) at http://localhost:56086/dwds/src/injected/client.js:25367:24 at _wrapJsFunctionForAsync_closure.$protected (http://localhost:56086/dwds/src/injected/client.js:3589:15) at _wrapJsFunctionForAsync_closure.call$2 (http://localhost:56086/dwds/src/injected/client.js:11698:12) at _awaitOnObject_closure.call$1 (http://localhost:56086/dwds/src/injected/client.js:11686:32) at StaticClosure._rootRunUnary (http://localhost:56086/dwds/src/injected/client.js:3948:18) at _CustomZone.runUnary$2$2 (http://localhost:56086/dwds/src/injected/client.js:13095:39) at _FuturepropagateToListeners_handleValueCallback.call$0 (http://localhost:56086/dwds/src/injected/client.js:12125:51) at Object._FuturepropagateToListeners (http://localhost:56086/dwds/src/injected/client.js:3731:93) at _Future._completeWithValue$1 (http://localhost:56086/dwds/src/injected/client.js:11956:9) at _AsyncAwaitCompleter.complete$1 (http://localhost:56086/dwds/src/injected/client.js:11672:14) at Object._asyncReturn (http://localhost:56086/dwds/src/injected/client.js:3561:17) at http://localhost:56086/dwds/src/injected/client.js:25344:24 at _wrapJsFunctionForAsync_closure.$protected (http://localhost:56086/dwds/src/injected/client.js:3589:15) at _wrapJsFunctionForAsync_closure.call$2 (http://localhost:56086/dwds/src/injected/client.js:11698:12) at _awaitOnObject_closure.call$1 (http://localhost:56086/dwds/src/injected/client.js:11686:32) at StaticClosure._rootRunUnary (http://localhost:56086/dwds/src/injected/client.js:3948:18) at _CustomZone.runUnary$2$2 (http://localhost:56086/dwds/src/injected/client.js:13095:39) at _FuturepropagateToListeners_handleValueCallback.call$0 (http://localhost:56086/dwds/src/injected/client.js:12125:51) at Object._FuturepropagateToListeners (http://localhost:56086/dwds/src/injected/client.js:3731:93) at _Future._completeWithValue$1 (http://localhost:56086/dwds/src/injected/client.js:11956:9) at _FutureasyncCompleteWithValue_closure.call$0 (http://localhost:56086/dwds/src/injected/client.js:12059:18) at StaticClosure._rootRun (http://localhost:56086/dwds/src/injected/client.js:3933:16) at _CustomZone.run$1$1 (http://localhost:56086/dwds/src/injected/client.js:13087:39) at _CustomZone.runGuarded$1 (http://localhost:56086/dwds/src/injected/client.js:13030:14) at _CustomZone_bindCallbackGuarded_closure.call$0 (http://localhost:56086/dwds/src/injected/client.js:13225:25) at Object._microtaskLoop (http://localhost:56086/dwds/src/injected/client.js:3792:24) at StaticClosure._startMicrotaskLoop (http://localhost:56086/dwds/src/injected/client.js:3798:11) at _AsyncRuninitializeScheduleImmediate_internalCallback.call$1 (http://localhost:56086/dwds/src/injected/client.js:11575:9) at invokeClosure (http://localhost:56086/dwds/src/injected/client.js:1238:26) at MutationObserver. (http://localhost:56086/dwds/src/injected/client.js:1257:18)

[elliette]

Interesting, this looks the same as https://github.com/dart-lang/webdev/issues/2332 which was resolved by updating to the latest Flutter stable (which you are already on).

Could you try the steps suggested here: https://github.com/dart-lang/webdev/issues/2332#issuecomment-1885432333

Thanks!

[kimemia21]

thanks , the issue disappeared after upgrading to version Flutter 3.19.4 • channel stable