NullReferenceException when loading a new log file without persistence data

[AndisGrossteins]

I'm seeing this on recent snapshot builds when loading a log file without saved persistence data:

2025-11-25 15:02:48.1585|ERROR|LogExpert.Core.Classes.Log.LogfileReader|System.NullReferenceException: Object reference not set to an instance of an object.Object reference not set to an instance of an object. System.NullReferenceException System.NullReferenceException: Object reference not set to an instance of an object.
   at LogExpert.UI.Controls.LogWindow.LogWindow.LoadPersistenceData() in D:\a\LogExpert\LogExpert\src\LogExpert.UI\Controls\LogWindow\LogWindow.cs:line 2489
   at System.Windows.Forms.Control.InvokeMarshaledCallbackDo(ThreadMethodEntry tme)
   at System.Windows.Forms.Control.InvokeMarshaledCallbackHelper(Object obj)
   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.Windows.Forms.Control.InvokeMarshaledCallbacks()
--- End of stack trace from previous location ---
   at System.Windows.Forms.Control.MarshaledInvoke(Control caller, Delegate method, Object[] args, Boolean synchronous)
   at System.Windows.Forms.Control.Invoke(Delegate method)
   at LogExpert.UI.Controls.LogWindow.LogWindow.OnLogFileReaderFinishedLoading(Object sender, EventArgs e) in D:\a\LogExpert\LogExpert\src\LogExpert.UI\Controls\LogWindow\LogWindow.cs:line 832
   at LogExpert.Core.Classes.Log.LogfileReader.OnLoadingFinished() in D:\a\LogExpert\LogExpert\src\LogExpert.Core\Classes\Log\LogfileReader.cs:line 1819
   at LogExpert.Core.Classes.Log.LogfileReader.MonitorThreadProc() in D:\a\LogExpert\LogExpert\src\LogExpert.Core\Classes\Log\LogfileReader.cs:line 1458

Closing and subsequently opening same log file doesn't produce the exception because there's a persistence file now.

Currently I'm running LogExpert snapshot downloaded yesterday from action run 19582622322.

[Hirogen]

interesting... since this is actually catched with

            if (persistenceData == null)
            {
                _logger.Info($"No persistence data for {FileName} found.");
                return;
            }

I just pushed a mr to the dev branch, could you test it with that one?

I can't reproduce that with the latest dev build

[AndisGrossteins]

Sorry, I didn't have time to dive deeper. Just thought you'd like to know if anything goes down since you're meticulously working and introducing large changes in the codebase.

[Hirogen]

yeah, thanks, I try to hunt it down

I tested this with a clean install and a logfile without persistence data and couldn't get the error, but maybe I'm missing something

I tested this now in a Windows Sandbox with no installation whatsoever, and a clean Logfile, and did not get the error message!

[AndisGrossteins]

I thought I'll just quickly start Visual Studio and debug this issue but instead got sidetracked installing Visual Studio 2026. Darned yak shaving.

I'll try to pin it down as soon as VS 2026 finishes installing.

[AndisGrossteins]

I could not reproduce this issue in recent snapshot builds before and now in 1.21.0 release.