DF.DeepFreezer.OnDestroy throwing NullReferenceExceptions in KSP 1.12.3 #108

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1. Lisias commented on May 14, 2022

   

   Lisias

   on May 14, 2022

   Last edited by Lisias

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   yeah, it was reported on net-lisias-ksp/KSP-Recall#40 too.

   I want to stress out that this was working perfectly fine on KSP 1.9.1, so it's something that changed on KSP itself for sure. Since this started to happen recently, I'm guessing that whatever changed on KSP, did it on 1.12.0.

   My best guess is that the problem is happening on this code:

   DeepFreeze/Source/DeepFreeze.cs

   Line 214 in 9f509f7

   protected void OnDestroy()

           protected void OnDestroy()
           {
               Utilities.Log("OnDestroy");
               Instance = null;
               APIReady = false;
               foreach (Component child in children)
               {
                   Utilities.Log("DeepFreeze Child Destroy for " + child.name);
                   Destroy(child);
               }
               children.Clear();
               DeepFreezeEventRem();
               GameEvents.onGameSceneLoadRequested.Remove(OnGameSceneLoadRequested);
               GameEvents.OnGameSettingsApplied.Remove(ApplySettings);
           }
   

   EDIT: NOPE!! I was fooled by a (unhappy) log message.
2. Lisias

   added 2 commits that reference this issue on May 14, 2022

   Fixing JPLRepo#108.

   ...

   c0f84c3

   Fixing JPLRepo#108.

   ...

   647824a
3. Lisias commented on May 14, 2022

   

   Lisias

   on May 14, 2022

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   KSP is not at fault here. This is what was really happening.

   The DeepFreezePart.OnDestroy (the PartModule) was the code borking, not the DeepFreeze.OnDestroy (the Scenario Module).

   That log message completely misguided me. The real problem is on this code:

   DeepFreeze/Source/DeepFreezerPart.cs

   Line 1813 in 9f509f7

   private void OnDestroy()

           private void OnDestroy()
           {
               //Remove GameEvent callbacks.
               Debug.Log("DeepFreezer OnDestroy");
               
                   GameEvents.onCrewTransferPartListCreated.Remove(onCrewTransferPartListCreated);
                   GameEvents.onCrewTransferred.Remove(onCrewTransferred);
                   GameEvents.onVesselChange.Remove(OnVesselChange);
                   GameEvents.onCrewBoardVessel.Remove(OnCrewBoardVessel);
                   GameEvents.onCrewOnEva.Remove(onCrewOnEva);
                   GameEvents.onVesselDestroy.Remove(onVesselDestroy);
                   GameEvents.OnCameraChange.Remove(OnCameraChange);
                   GameEvents.onVesselGoOffRails.Remove(onVesselGoOffRails);
                   GameEvents.onVesselCrewWasModified.Remove(OnVesselCrewModified);
                   DFGameEvents.onKerbalFrozen.Remove(OnKerbalFreezeThaw);     // <— HERE!!!
                   DFGameEvents.onKerbalThaw.Remove(OnKerbalFreezeThaw);
                   GameEvents.onVesselSwitching.Remove(OnVesselSwitching);
                   if (onATPPodSettingChanged != null)
                   {
                       onATPPodSettingChanged.Remove(OnATPPodSettingChanged);
                   }
               
               Debug.Log("DeepFreezer END OnDestroy");
           }
   

   The DGGameEvents structure os initialised only on the class Textures (whatahell??) on the Start method, here:

   DeepFreeze/Source/Textures.cs

   Line 33 in 9f509f7

   public void Start()

   Problem. Besides Textures being completely unrelated to the DFGameEvents, the Texture MonoBehaviour is started only on the Main Menu : [KSPAddon(KSPAddon.Startup.MainMenu, false)]. So it's not a surprise that the DeepFreezePart's OnDestroy is borking, as the DFGameEvents are all still NULL at that point!

   The easiest way out of this huge mess is to initialise DFGameEvents on the class loading, guaranteeing that the data structures will be immediately available for using.

   The big question is not why DF started to throw exceptions now, but why it wasn't doing it before.
4. Lisias commented on May 14, 2022

   

   Lisias

   on May 14, 2022

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   A pull request was issued fixing the issue.

   #110
5. JPLRepo commented on May 15, 2022

   

   JPLRepo

   on May 15, 2022

   Owner

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   Will be fixed in next release. Hopefully I can get that done this coming week.
6. c-pashayev commented on Aug 4, 2022

   

   c-pashayev

   on Aug 4, 2022

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   @JPLRepo
   Good day sir! Recently I ran into a similar problem and the mod crashed a game for me.
   Do you have any spare time to release an updated build with those fixes?