initERacksActive throws NRE on OnStart when IVA placeholder mode is active (KSP Community Fixes)

[liltine]

Environment:

OMS/NEOS 0.10.0
KSP 1.12.5
KSP Community Fixes installed, with IVA handling set to "placeholder" mode

Summary:

With KSPCF's IVA placeholder mode enabled, both MPL_Module and MSL_Module throw a NullReferenceException in initERacksActive() during OnStart. Because the exception aborts OnStart, the labs never finish initializing and the equipment install action is never registered — equipment carriers dock/sit on the same vessel with correct equipment, but no install option ever appears on the lab or carrier.
Root cause:

initERacksActive() guards only on part.internalModel != null. In placeholder IVA mode the internal model object exists (non-null) but lacks the expected mesh hierarchy, so:

csharpGameObject labIVA = part.internalModel.gameObject.transform.GetChild(0).GetChild(0).gameObject;
if (labIVA.GetComponent<MeshFilter>().name == "Lab1IVA")  // GetComponent returns null → .name throws
GetComponent<MeshFilter>() returns null and .name throws.

Stack trace:

[EXC 17:07:51.072] NullReferenceException: Object reference not set to an instance of an object
	NE_Science.MPL_Module.initERacksActive () (at <a6ea64e79c044aaca2123ac101d1d50c>:0)
	NE_Science.MPL_Module.updateLabStatus () (at <a6ea64e79c044aaca2123ac101d1d50c>:0)
	NE_Science.Lab.updateStatus () (at <a6ea64e79c044aaca2123ac101d1d50c>:0)
	NE_Science.Lab+<updateState>d__30.MoveNext () (at <a6ea64e79c044aaca2123ac101d1d50c>:0)
	UnityEngine.SetupCoroutine.InvokeMoveNext (System.Collections.IEnumerator enumerator, System.IntPtr returnValueAddress) (at <12e76cd50cc64cf19e759e981cb725af>:0)
	UnityEngine.DebugLogHandler:LogException(Exception, Object)
	ModuleManager.UnityLogHandle.InterceptLogHandler:LogException(Exception, Object)
	UnityEngine.MonoBehaviour:StartCoroutine(IEnumerator)
	NE_Science.Lab:OnStart(StartState)
	NE_Science.MPL_Module:OnStart(StartState)
	Part:ModulesOnStart()
	<Start>d__323:Part+<Start>d__323.MoveNext_Patch0(<Start>d__323)
	UnityEngine.SetupCoroutine:InvokeMoveNext(IEnumerator, IntPtr)
[ERR 17:07:51.073] Module MPL_Module threw during OnStart: System.NullReferenceException: Object reference not set to an instance of an object
  at NE_Science.MPL_Module.initERacksActive () [0x00043] in <a6ea64e79c044aaca2123ac101d1d50c>:0 
  at NE_Science.MPL_Module.OnStart (PartModule+StartState state) [0x0000c] in <a6ea64e79c044aaca2123ac101d1d50c>:0 
  at Part.ModulesOnStart () [0x00120] in <4b449f2841f84227adfaad3149c8fdba>:0 

[LOG 17:07:51.073] -INFO- Tac.LifeSupportModule[FFDB07E2][317.78]: OnStart: PreLaunch, Landed
[EXC 17:07:51.074] NullReferenceException: Object reference not set to an instance of an object
	NE_Science.MSL_Module.initERacksActive () (at <a6ea64e79c044aaca2123ac101d1d50c>:0)
	NE_Science.MSL_Module.updateLabStatus () (at <a6ea64e79c044aaca2123ac101d1d50c>:0)
	NE_Science.Lab.updateStatus () (at <a6ea64e79c044aaca2123ac101d1d50c>:0)
	NE_Science.Lab+<updateState>d__30.MoveNext () (at <a6ea64e79c044aaca2123ac101d1d50c>:0)
	UnityEngine.SetupCoroutine.InvokeMoveNext (System.Collections.IEnumerator enumerator, System.IntPtr returnValueAddress) (at <12e76cd50cc64cf19e759e981cb725af>:0)
	UnityEngine.DebugLogHandler:LogException(Exception, Object)
	ModuleManager.UnityLogHandle.InterceptLogHandler:LogException(Exception, Object)
	UnityEngine.MonoBehaviour:StartCoroutine(IEnumerator)
	NE_Science.Lab:OnStart(StartState)
	NE_Science.MSL_Module:OnStart(StartState)
	Part:ModulesOnStart()
	<Start>d__323:Part+<Start>d__323.MoveNext_Patch0(<Start>d__323)
	UnityEngine.SetupCoroutine:InvokeMoveNext(IEnumerator, IntPtr)
[ERR 17:07:51.074] Module MSL_Module threw during OnStart: System.NullReferenceException: Object reference not set to an instance of an object
  at NE_Science.MSL_Module.initERacksActive () [0x00043] in <a6ea64e79c044aaca2123ac101d1d50c>:0 
  at NE_Science.MSL_Module.OnStart (PartModule+StartState state) [0x0000c] in <a6ea64e79c044aaca2123ac101d1d50c>:0 
  at Part.ModulesOnStart () [0x00120] in <4b449f2841f84227adfaad3149c8fdba>:0 

[LOG 17:07:51.075] -INFO- Tac.LifeSupportModule[FFDB07C8][317.78]: OnStart: PreLaunch, Landed

Repro:

Install KSP Community Fixes, set IVA mode to placeholder.
Place an MPL-600 or MSL-1000 on the pad (crewed, with an equipment carrier on the same vessel).
Observe the NRE in KSP.log during flight load; no install action appears on the lab.

Workaround:

Re-enable full IVA loading (disable placeholder mode). Install action returns.

[mwerle]

"In placeholder IVA mode the internal model object exists (non-null) but lacks the expected mesh hierarchy, so:"

In this case I suspect that the entire mod will require a significant rewrite, since it relies heavily on the IVA being "correct". When lab equipment and experiments are installed or removed, various IVA components are enabled or disabled, animations started/stopped, etc etc. It's pretty intertwined and embedded.

I'm sorry, but this is going to be pretty low on my priorities list - I can't really be expected to implement workarounds for other mods actively breaking this mod..

That said, thank you for the detailed report; if I do end up with some significant spare time, I will take a look. Alternatively if the fix isn't as complicated and involved as I suspect it will be, I'll happily accept a PR. But if the PR is "big", then I'm sorry, I'll likely be unable to spend the time to perform a detailed review and accept it either.