NullReferenceException in MySqlConnection.Cancel

[dmathijs]

MySqlConnector version: 2.3.1
Server type (MySQL, MariaDB, Aurora, etc.) and version: MariaDb
.NET version: 8.0.302
(Optional) ORM NuGet packages and versions: Pomelo.EntityFrameworkCore.MySql

Today I got this stacktrace on my server:

Unhandled exception. System.NullReferenceException: Object reference not set to an instance of an object.
   at MySqlConnector.MySqlConnection.Cancel(ICancellableCommand command, Int32 commandId, Boolean isCancel) in /_/src/MySqlConnector/MySqlConnection.cs:line 762
   at MySqlConnector.MySqlCommand.CancelCommandForTimeout() in /_/src/MySqlConnector/MySqlCommand.cs:line 439
   at MySqlConnector.Utilities.TimerQueue.Callback(Object obj) in /_/src/MySqlConnector/Utilities/TimerQueue.cs:line 98
   at System.Threading.ExecutionContext.RunInternal(ExecutionContext executionContext, ContextCallback callback, Object state)
--- End of stack trace from previous location ---
   at System.Threading.ExecutionContext.RunInternal(ExecutionContext executionContext, ContextCallback callback, Object state)
   at System.Threading.TimerQueueTimer.Fire(Boolean isThreadPool)
   at System.Threading.TimerQueue.FireNextTimers()
   at System.Threading.ThreadPoolWorkQueue.Dispatch()
   at System.Threading.PortableThreadPool.WorkerThread.WorkerThreadStart()

I noticed that back in 2022, there was a fix done for this exact issue:

• NullReferenceException in MySqlConnector.Utilities.TimerQueue.Callback #1177
• eadb98c

However, this seems to be re-factored away and it seems like this bug was re-introduced at some point.
000f586
e82f091

The problem is that I don't know enough about the code-base to know whether adding null conditional operators is allowed, can someone give me some pointers?

[bgrainger]

This does look like a bug that was reintroduced in e82f091; thanks for the analysis.

[dmathijs]

Thank you!

[bgrainger]

Fixed in 2.4.0.