Ckan: NullReferenceException at launch in GUIMod constructor

[cculianu]

NOTE: CKAN 1.25.1 runs just fine. This is only an issue on 1.25.2.

Background

CKAN Version: 1.25.2

KSP Version: 1.4.5.2243

Operating System: macOS X 10.13.6 with Mono: Mono JIT compiler version 5.12.0.226 (2018-02/9824e260f56 Mon Apr 30 18:29:27 EDT 2018)

Have you made any manual changes to your GameData folder (i.e., not via CKAN)? NO

Problem

What steps did you take in CKAN? Started it from command-line as I always do: mono ckan.exe

What did you expect to happen? CKAN to run and not crash.

What happened instead? CKAN Crashed with a stack trace (previous version, 1.25.1 runs just fine)

Screenshots:

CKAN error codes (if applicable):

[HebaruSan]

The only statement with Select and Where in GUIMod's constructor is the calculation of the abbreviation:

https://github.com/KSP-CKAN/CKAN/blob/10efed501a94f65d6a1ee7a5f5af956af41ff8b5/GUI/GUIMod.cs#L241-L244

That code hasn't changed in 3 years.
EDIT: Oops, got the order of the stack trace wrong. The null ref happens in GUIMod's constructor, but the Select and Where calls are somewhere in _UpdateModsList:

https://github.com/KSP-CKAN/CKAN/blob/10efed501a94f65d6a1ee7a5f5af956af41ff8b5/GUI/MainModList.cs#L142-L147

@cculianu, do you have a 32-bit OS? I'm surprised that you were having success previously running just mono ckan.exe; usually Mac users have to run mono --arch=32 ckan.exe instead.

[HebaruSan]

Checking the changes to GUIMod's constructor since 1.25.1, it's looking like this is caused by @yalov's project to tinker with how versions are displayed in #2437...

[cculianu]

@HebaruSan -- I have a 64-bit OS on a relatively recent macbook pro. Actually it's always worked for me without --arch=32. Didn't even know about that option.

EDIT: It crashes exactly the same with --arch=32.. And 1.25.1 still works the same.

[cculianu]

PS: CKAN always gave a stacktrace on exit - but it ran. So FYI this is what I get on exit in 1.25.1:

System.NullReferenceException: Object reference not set to an instance of an object
  at System.Windows.Forms.ToolStripDropDownMenu.CalculateConnectedArea () [0x00038] in <beba0b11547e4333a33d4d8cdf7b7c51>:0 
  at System.Windows.Forms.ToolStripDropDownMenu.OnPaintBackground (System.Windows.Forms.PaintEventArgs e) [0x00025] in <beba0b11547e4333a33d4d8cdf7b7c51>:0 
  at System.Windows.Forms.Control.WmPaint (System.Windows.Forms.Message& m) [0x0005e] in <beba0b11547e4333a33d4d8cdf7b7c51>:0 
  at System.Windows.Forms.Control.WndProc (System.Windows.Forms.Message& m) [0x001a4] in <beba0b11547e4333a33d4d8cdf7b7c51>:0 
  at System.Windows.Forms.ScrollableControl.WndProc (System.Windows.Forms.Message& m) [0x00000] in <beba0b11547e4333a33d4d8cdf7b7c51>:0 
  at System.Windows.Forms.ToolStrip.WndProc (System.Windows.Forms.Message& m) [0x00000] in <beba0b11547e4333a33d4d8cdf7b7c51>:0 
  at System.Windows.Forms.ToolStripDropDown.WndProc (System.Windows.Forms.Message& m) [0x00017] in <beba0b11547e4333a33d4d8cdf7b7c51>:0 
  at System.Windows.Forms.Control+ControlWindowTarget.OnMessage (System.Windows.Forms.Message& m) [0x00000] in <beba0b11547e4333a33d4d8cdf7b7c51>:0 
  at System.Windows.Forms.Control+ControlNativeWindow.WndProc (System.Windows.Forms.Message& m) [0x0000b] in <beba0b11547e4333a33d4d8cdf7b7c51>:0 
  at System.Windows.Forms.NativeWindow.WndProc (System.IntPtr hWnd, System.Windows.Forms.Msg msg, System.IntPtr wParam, System.IntPtr lParam) [0x00085] in <beba0b11547e4333a33d4d8cdf7b7c51>:0 
Waiting on threads to park on joinable thread list timed out.

[HebaruSan]

Thanks, that other exception would probably be best reported to Mono, since there's no CKAN code in the stack trace.

[HebaruSan]

@cculianu, can you please try this test build? It will not fix the problem, but it should give a slightly different error message telling us which mod caused the exception, which in turn ought to give us clues as to what exactly is going wrong:

• (link removed, see #2486 for new test build)

[cculianu]

@HebaruSan Ok, I ran the ckan.exe from the .zip you gave me -- here is the stack trace/debug output:

calin@CalinMBP2016 ~/Library/Application Support/Steam/steamapps/common/Kerbal Space Program/CKAN $ mono ~/tmp/ckan-dbg.exe 
System.Exception: Failed to construct a GUIMod for MiniAVC 1.0.3.0 (Object reference not set to an instance of an object)
  at CKAN.GUIMod..ctor (CKAN.CkanModule mod, CKAN.IRegistryQuerier registry, CKAN.Versioning.KspVersionCriteria current_ksp_version, System.Boolean incompatible) [0x003d6] in <60e037f139274e47b1d6c0206eefe140>:0 
  at CKAN.Main+<>c__DisplayClass229_0.<_UpdateModsList>b__2 (CKAN.InstalledModule m) [0x00006] in <60e037f139274e47b1d6c0206eefe140>:0 
  at System.Linq.Enumerable+SelectEnumerableIterator`2[TSource,TResult].MoveNext () [0x00048] in <cc3b329d40bd4675ae0e985e302972af>:0 
  at System.Linq.Enumerable+WhereEnumerableIterator`1[TSource].MoveNext () [0x0004e] in <cc3b329d40bd4675ae0e985e302972af>:0 
  at CKAN.Main._UpdateModsList (System.Boolean repo_updated, System.Collections.Generic.List`1[T] mc) [0x000fe] in <60e037f139274e47b1d6c0206eefe140>:0 
  at CKAN.Main+<>c__DisplayClass228_0.<UpdateModsList>b__0 () [0x0001b] in <60e037f139274e47b1d6c0206eefe140>:0 
  at CKAN.Util.Invoke[T] (T obj, System.Action action) [0x0002d] in <60e037f139274e47b1d6c0206eefe140>:0 
  at CKAN.Main.UpdateModsList (System.Boolean repo_updated, System.Collections.Generic.List`1[T] mc) [0x0001c] in <60e037f139274e47b1d6c0206eefe140>:0 
  at CKAN.Main.CurrentInstanceUpdated () [0x00062] in <60e037f139274e47b1d6c0206eefe140>:0 
  at CKAN.Main.OnLoad (System.EventArgs e) [0x002c2] in <60e037f139274e47b1d6c0206eefe140>:0 
  at System.Windows.Forms.Form.OnLoadInternal (System.EventArgs e) [0x00023] in <beba0b11547e4333a33d4d8cdf7b7c51>:0 
Waiting on threads to park on joinable thread list timed out.

[HebaruSan]

@cculianu, thanks! That is a huge clue, gives a lot of info that should hopefully lead to a fix (it's trying to make a GUI row for MiniAVC, which isn't a module proper, so we need to check the code for loading stray DLLs. It also confirms that #2437 is responsible.).

@TACHYON-Micah, you have @barfingskull's issue, not @cculianu's, already fixed in #2482. Once we have these both fixed I imagine @politas will want to put out a hotfix release.

[HebaruSan]

@barfingskull and @TACHYON-Micah, your issue is being tracked at #2483. I'll migrate your comments over there as best as I can.