RoundManagerObjectReferenceFix

ℹ️ Only the host is required to install this mod. Should be fine for multiplayer and could potentially prevent crashes on other custom moons too.

A mod for Lethal Company that prevents crashes caused by unresolved prefab references in custom moon mods.

What it does

ℹ️ I created this mod for my own moon as I assigned blank references to the corresponding fields (to keep the mod size small), but the game could not resolve them and crash.

This mod runs during the spawn process of the RoundManager and tries to detect scrap, outside objects, and map hazards that do not have a prefab ( prefab = null). It does the following when a prefab = null:

• Scrap items:
  • If an item has a null prefab, it is replaced with a random valid item from the moon's item spawn list
• Outside objects:
  • If an outside object has a null prefab, it is removed from the spawn pool to prevent a crash
• Map objects:
  • If an Indoor hazard has a null prefab, it is removed from the spawn pool to prevent a crash

Logging is included so you can identify which objects are not resolving correctly and fix them in your moon configuration.

Example errors

On spawn outside hazards:

[Error  : Unity Log] ArgumentException: The Object you want to instantiate is null.
Stack trace:
UnityEngine.Object.Instantiate (UnityEngine.Object original, UnityEngine.Vector3 position, UnityEngine.Quaternion rotation, UnityEngine.Transform parent) (at <c39a522eee05469b8171a6cfeb646c59>:IL_0048)
UnityEngine.Object.Instantiate[T] (T original, UnityEngine.Vector3 position, UnityEngine.Quaternion rotation, UnityEngine.Transform parent) (at <c39a522eee05469b8171a6cfeb646c59>:IL_0001)
RoundManager.SpawnOutsideHazards () (at <aca1e98d6f844d3f85cd22b6f7be2f9b>:IL_049F)
DMD<>?434046712.Trampoline<RoundManager::SpawnOutsideHazards>?-426100634 (RoundManager ) (at <6ab606ea172a41089b084a0fac1d3b4f>:IL_0025)
Dawn.MapObjectRegistrationHandler.SpawnOutsideMapObjects (On.RoundManager+orig_SpawnOutsideHazards orig, RoundManager self) (at ./src/API/MapObjects/.MapObjectRegistrationHandler.cs:275)
DMD<>?1224120700.Hook<RoundManager::SpawnOutsideHazards>?1737978544 (RoundManager ) (at <08e77660bbec49c79358861a9942a2e8>:IL_000F)
RoundManager.FinishGeneratingLevel () (at <aca1e98d6f844d3f85cd22b6f7be2f9b>:IL_0040)
RoundManager.Generator_OnGenerationStatusChanged (DunGen.DungeonGenerator generator, DunGen.GenerationStatus status) (at <aca1e98d6f844d3f85cd22b6f7be2f9b>:IL_000C)
DunGen.DungeonGenerator.ChangeStatus (DunGen.GenerationStatus status) (at <761948217ee64e61867b0efbfe186c99>:IL_0036)
DunGen.DungeonGenerator+<InnerGenerate>d__131.MoveNext () (at <761948217ee64e61867b0efbfe186c99>:IL_049E)
UnityEngine.SetupCoroutine.InvokeMoveNext (System.Collections.IEnumerator enumerator, System.IntPtr returnValueAddress) (at <c39a522eee05469b8171a6cfeb646c59>:IL_0026)

On spawning scrap

[Error  : Unity Log] ArgumentException: The Object you want to instantiate is null.
Stack trace:
UnityEngine.Object.Instantiate (UnityEngine.Object original, UnityEngine.Vector3 position, UnityEngine.Quaternion rotation) (at <c39a522eee05469b8171a6cfeb646c59>:IL_0049)
UnityEngine.Object.Instantiate (UnityEngine.Object original, UnityEngine.Vector3 position, UnityEngine.Quaternion rotation, UnityEngine.Transform parent) (at <c39a522eee05469b8171a6cfeb646c59>:IL_000C)
UnityEngine.Object.Instantiate[T] (T original, UnityEngine.Vector3 position, UnityEngine.Quaternion rotation, UnityEngine.Transform parent) (at <c39a522eee05469b8171a6cfeb646c59>:IL_0001)
RoundManager.SpawnScrapInLevel () (at <aca1e98d6f844d3f85cd22b6f7be2f9b>:IL_0540)
DMD<>?2052090776.Trampoline<RoundManager::SpawnScrapInLevel>?1603470438 (RoundManager ) (at <ba2f074d161c45b7b28b375f042274b3>:IL_0025)
Dawn.ItemRegistrationHandler.UpdateItemWeights (On.RoundManager+orig_SpawnScrapInLevel orig, RoundManager self) (at ./src/API/Items/.ItemRegistrationHandler.cs:107)
DMD<>?1148133988.Hook<RoundManager::SpawnScrapInLevel>?1662684564 (RoundManager ) (at <0fc5dc6ba0e8494d96b22eb435ae30a3>:IL_000F)
RoundManager.GeneratedFloorPostProcessing () (at <aca1e98d6f844d3f85cd22b6f7be2f9b>:IL_0009)
RoundManager+<LoadNewLevelWait>d__167.MoveNext () (at <aca1e98d6f844d3f85cd22b6f7be2f9b>:IL_05C5)
UnityEngine.SetupCoroutine.InvokeMoveNext (System.Collections.IEnumerator enumerator, System.IntPtr returnValueAddress) (at <c39a522eee05469b8171a6cfeb646c59>:IL_0026)

Example of the fix

Outside "hazards" / objects:

[Info   :RoundManagerObjectReferenceFix] Checking: SpawnOutsideHazards
[Info   :RoundManagerObjectReferenceFix] Outside object 'SnowmanShort' | Prefab: Snowman OK
[Info   :RoundManagerObjectReferenceFix] Outside object 'SnowmanTall' | Prefab: SnowmanTall OK
[Warning:RoundManagerObjectReferenceFix] Outside object 'TreeLeafless2Snowy' has null prefab, resolving from vanilla level
[Warning:RoundManagerObjectReferenceFix] Outside object 'SmallGreyRocks2' has null prefab, resolving from vanilla level
[Warning:RoundManagerObjectReferenceFix] Outside object 'SmallGreyRocks1' has null prefab, resolving from vanilla level
[Warning:RoundManagerObjectReferenceFix] Outside object 'TreeLeafless3Snowy' has null prefab, resolving from vanilla level

scrap:

[Info   : Unity Log] Dungeon has finished generating on this client after multiple frames
[Info   : Unity Log] Players finished generating the new floor
[Info   : Unity Log] Spawning synced props on server. Length: 39
[Info   :RoundManagerObjectReferenceFix] Checking: SpawnScrapInLevel
[Warning:RoundManagerObjectReferenceFix] Scrap item 'CardboardBox' has null prefab, replacing with 'Flask'
[Info   : Unity Log] Number of scrap to spawn: 24. minTotalScrapValue: 500. Total value of items: 0.

MapObjects "indoor hazards":

[Info   :RoundManagerObjectReferenceFix] Checking: SpawnMapObjects
[Warning:RoundManagerObjectReferenceFix] Indoor hazard 'Turrets' has null prefab, resolving from vanilla level
[Warning:RoundManagerObjectReferenceFix] Indoor hazard 'SpikeTraps' has null prefab, resolving from vanilla level
[Warning:RoundManagerObjectReferenceFix] Indoor hazard 'Landmines' has null prefab, resolving from vanilla level
[Info   : Unity Log] TurretScript creating doorcode object in parent MapScreenUIWorldSpace (UnityEngine.RectTransform): DoorCodeUIObject(Clone)
[Info   : Unity Log] TerminalObjectContainer creating doorcode object in parent MapScreenUIWorldSpace (UnityEngine.RectTransform): DoorCodeUIObject(Clone)
[Info   : Unity Log] Landmine creating doorcode object in parent MapScreenUIWorldSpace (UnityEngine.RectTransform): DoorCodeUIObject(Clone)

AI usage

I used claude to assist me during development, and find potential issues/bugs.

Changelog

1.0.1

• Scrap items with a null prefab are now replaced by a scrap item of similar value from the moon's spawn list. If the item has no value range to compare, a random valid item is used as before.
• Outside objects and indoor hazards with a null prefab are first resolved from a vanilla level's object with the same name. They are only removed from the spawn pool when no match exists.
• The mod can no longer cause a crash itself: if one of its checks fails, the error is logged and the game continues as it would without the mod.
• Repeated log messages are now logged once per session instead of on every level load.
• Warnings for outside object entries without a spawnableObject now show the entry index and the moon name, so the broken entry is easy to find.

1.0.0

• Initial release.
• Replaces scrap with a null prefab with a valid item from the moon's spawn list.
• Removes outside objects and indoor hazards with a null prefab from the spawn pool to prevent a crash.