[🐛 Bug]: Entire application crash in case of unhandled exception in `async void` method

[nvborisenko]

What happened?

Application is crashed.

How can we reproduce the issue?

Open `youtube.com` with enabled network monitoring.


var net = driver.Manage().Network;

        net.NetworkRequestSent += (sender, e) =>
        {
            //Console.WriteLine(e.RequestUrl);
        };

Relevant log output

Running selected tests in D:\Temp\aaa\bin\Debug\net7.0\aaa.dll
   NUnit3TestExecutor discovered 1 of 1 NUnit test cases using Current Discovery mode, Non-Explicit run
The active test run was aborted. Reason: Test host process crashed : Unhandled exception. System.NullReferenceException: Object reference not set to an instance of an object.
   at aaa.UnitTest1.<>c__DisplayClass0_0.<Test1>b__2(Object sender, NetworkResponseReceivedEventArgs e) in D:\Temp\aaa\UnitTest1.cs:line 31
   at OpenQA.Selenium.NetworkManager.OnResponsePaused(Object sender, ResponsePausedEventArgs e)
   at System.Threading.Tasks.Task.<>c.<ThrowAsync>b__128_1(Object state)
   at System.Threading.QueueUserWorkItemCallback.Execute()
   at System.Threading.ThreadPoolWorkQueue.Dispatch()
   at System.Threading.PortableThreadPool.WorkerThread.WorkerThreadStart()

### Operating System

any

### Selenium version

any

### What are the browser(s) and version(s) where you see this issue?

any

### What are the browser driver(s) and version(s) where you see this issue?

any

### Are you using Selenium Grid?

_No response_

[github-actions]

@nvborisenko, thank you for creating this issue. We will troubleshoot it as soon as we can.

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Thank you!

[nvborisenko]

It happens because of async void as event handler: https://github.com/SeleniumHQ/selenium/blob/fbfa5d26ce96ca067d62b6921915e640498e3b09/dotnet/src/webdriver/NetworkManager.cs#L215C9-L215C9

We should refactor it to async Task or just void.

[diemol]

Thank you for reporting this and pointing out the issue. Which option would be better?

[nvborisenko]

async Task is better, it allows us use await in the body. But changing method signature might be a breaking change (hopefully no, seems it's not public).

Otherwise plan B: just void and changing all awaits to Task.Run().GetAwaiter().GetResult().

[github-actions]

This issue has been automatically locked since there has not been any recent activity after it was closed. Please open a new issue for related bugs.