Strange issue in .NET 4.8.1 WinForms app

[BTPDarren]

I have been using my own copy of this for sometime now, I modified to have a Preprocess batch file to allow me to clear down only specific files (*.DLL and *.EXE) and leave all the others.

Due to issues with other things I have removed this and installed the current version from Nuget.

I have come across a very strange issue with it in how I have implemented.

I have created the XML as always

<?xml version="1.0" encoding="UTF-8"?>
<item>
  <version>1.2024.618.1350</version>
  <url>https://.../mothership/Updates/Test/AppUpdates/BTPCaseManagement_1_2024_619_1000/Update.zip</url>
  <changelog>https://.../mothership/Updates/Test/AppUpdates/BTPCaseManagement_1_2024_619_1000/Update.txt</changelog>
  <mandatory>false</mandatory>
<args>--clear</args>
</item>

I do a update check in the app startup

   [STAThread]
   static void Main(string[] args)
   {
           AppHelper.CheckAppUpdate(false, true);
            if (AppHelper.restartApp)
            {
                Application.Exit();
            }
            else
            {
                SingleInstanceApp myApp = new SingleInstanceApp();
                myApp.Run(args);
             }
}

The CheckAppUpdate method

public static void CheckAppUpdate(bool force = false, bool syncronous = false)
        {
            AutoUpdater.Mandatory = false;
            AutoUpdater.ReportErrors = true;
            AutoUpdater.ClearAppDirectory = false;
            AutoUpdater.RunUpdateAsAdmin = false;
            AutoUpdater.UpdateFormSize = new Size(600, 500);
            if (force)
            {
                AutoUpdater.Mandatory = true;
            }
            AutoUpdater.Synchronous = syncronous;

            //AutoUpdater.Start(settingsObjectGlobal.ApplicationUpdatePath);
            AutoUpdater.CheckForUpdateEvent += AutoUpdaterOnCheckForUpdateEvent;
            AutoUpdater.Start("https://..../mothership/Updates/Test/WebUpdate.xml");
        }

The Update Check event

       public static void AutoUpdaterOnCheckForUpdateEvent(UpdateInfoEventArgs args)
       {
           if (args?.Error == null)
           {
               if (args.IsUpdateAvailable)
               {
                   if (args.InstallerArgs.Contains("--clear"))
                   {
                       AutoUpdater.ClearAppDirectory = true;
                   }
                   AutoUpdater.ApplicationExitEvent += AutoUpdater_ApplicationExitEvent;
                   AutoUpdater.ShowUpdateForm(args);

               }
           }
           else
           {
               if (args.Error is WebException)
               {
                   MessageBox.Show(
                       @"There is a problem reaching update server. Please check your internet connection and try again later.",
                       @"Update Check Failed", MessageBoxButtons.OK, MessageBoxIcon.Error);
               }
               else
               {
                   MessageBox.Show(args.Error.Message,
                       args.Error.GetType().ToString(), MessageBoxButtons.OK,
                       MessageBoxIcon.Error);
               }
           }
       }

I am doing this because I need to determine if the directory should be cleared or not based on the XML config so I can push small patches with just a few files, I would toggle the --clear

The issue
if I have the entry in the XML <args>--clear</args> every thing works perfectly.
however
if I omit the entire args entry I get the following error and to fix it I have to have a blank args entry : <args></args>

Testing indicates the args is null, until I inspect it!

Ultimately the fix is to add the blank args but the args is supposed to be optional!

Ideas?

[ravibpatel]

It is a strange issue indeed. I checked code and args should not be null in any case. Is it possible to provide the full stack trace or is it possible to reproduce this on a Test project, so I can check it out?

[BTPDarren]

Turns out this is not an issue after all.
In Release mode, the error is as shown, in Debug I spotted I was testing the args.InstallerArgs args.InstallerArgs.Contains("--clear") However I did not realize, no args meant InstallerArgs would be null (of course it would be)
I added a test for null on the appropriate line and all is good.

Sorry, sometimes its too easy to miss the obvious!

 if (!string.IsNullOrEmpty(args.InstallerArgs) &&  args.InstallerArgs.Contains("--clear"))
 {
     AutoUpdater.ClearAppDirectory = true;
 }