[Bug]:NRE when riposte kills attacker

[masakitenchi]

Complete the template below. Reports that do not follow the template will be deleted.
Title should be: [Bug]: (Short description of bug)

Specifications
Please provide the following.

Rimworld version: 1.5.4297
Combat Extended version: workshop latest
Combat Extended source (Steam, GitHub, etc.): steam
Your operating system: windows 10
Your mod list:

Initializing new game with mods:
  - brrainz.harmony
  - Ludeon.RimWorld
  - Ludeon.RimWorld.Royalty
  - Ludeon.RimWorld.Ideology
  - Ludeon.RimWorld.Biotech
  - Ludeon.RimWorld.Anomaly
  - CETeam.CombatExtended

Description
Provide a concise description of the issue or concern. What happened?
when riposte attack kills its opponent, game always throws a NRE in Verse.Verb.TryCastNextBurstShot
Expected behavior
What did you expect to happen?
No error, of course
To reproduce
Provide clear steps to reproduce the behavior. How do we make this happen?

• Have enemies on map
• Spawn or find a pawn with high melee
• Give him/her a good weapon so that riposte has a good probability to kill its opponent
• Wait

Screenshots & log dumps
I'll just post the whole log here. It's not that long. Also trimmed lines that has nothing to do with this error

RimWorld 1.5.4297 rev1079 
(Filename: C:\buildslave\unity\build\Runtime/Export/Debug/Debug.bindings.h Line: 39)

Unloading 5 Unused Serialized files (Serialized files now loaded: 4)
UnloadTime: 0.315000 ms

Unloading 969 unused Assets to reduce memory usage. Loaded Objects now: 26588.
Total: 278.024400 ms (FindLiveObjects: 0.992500 ms CreateObjectMapping: 0.603400 ms MarkObjects: 275.539000 ms  DeleteObjects: 0.889100 ms)

Initializing new game with mods:
  - brrainz.harmony
  - Ludeon.RimWorld
  - Ludeon.RimWorld.Royalty
  - Ludeon.RimWorld.Ideology
  - Ludeon.RimWorld.Biotech
  - Ludeon.RimWorld.Anomaly
  - CETeam.CombatExtended 
(Filename: C:\buildslave\unity\build\Runtime/Export/Debug/Debug.bindings.h Line: 39)

Exception in JobDriver tick for pawn Megascarab9587 driver=JobDriver_AttackMelee (toilIndex=2)
System.NullReferenceException: Object reference not set to an instance of an object
[Ref 4B2E07C]
 at Verse.Verb.TryCastNextBurstShot () [0x002d0] in <69945a8ed6c540cf90b578de735e0605>:0 
     - TRANSPILER CombatExtended.HarmonyCE: IEnumerable`1 CombatExtended.HarmonyCE.Harmony_Verb_TryCastNextBurstShot:Transpiler(IEnumerable`1 instructions, ILGenerator generator)
 at Verse.Verb.WarmupComplete () [0x00013] in <69945a8ed6c540cf90b578de735e0605>:0 
 at CombatExtended.Verb_MeleeAttackCE.WarmupComplete () [0x00008] in <d4f808b7eac94548b83685e1520170fc>:0 
 at Verse.Verb.TryStartCastOn (Verse.LocalTargetInfo castTarg, Verse.LocalTargetInfo destTarg, System.Boolean surpriseAttack, System.Boolean canHitNonTargetPawns, System.Boolean preventFriendlyFire, System.Boolean nonInterruptingSelfCast) [0x001c8] in <69945a8ed6c540cf90b578de735e0605>:0 
     - TRANSPILER CombatExtended.HarmonyCE: IEnumerable`1 CombatExtended.HarmonyCE.Harmony_Verb_TryStartCastOn:Transpiler(IEnumerable`1 instructions, ILGenerator generator)
 at Verse.Verb.TryStartCastOn (Verse.LocalTargetInfo castTarg, System.Boolean surpriseAttack, System.Boolean canHitNonTargetPawns, System.Boolean preventFriendlyFire, System.Boolean nonInterruptingSelfCast) [0x00007] in <69945a8ed6c540cf90b578de735e0605>:0 
 at RimWorld.Pawn_MeleeVerbs.TryMeleeAttack (Verse.Thing target, Verse.Verb verbToUse, System.Boolean surpriseAttack) [0x0009f] in <69945a8ed6c540cf90b578de735e0605>:0 
 at Verse.AI.JobDriver_AttackMelee.<MakeNewToils>b__4_2 () [0x0003d] in <69945a8ed6c540cf90b578de735e0605>:0 
 at Verse.AI.Toils_Combat+<>c__DisplayClass6_0.<FollowAndMeleeAttack>b__0 () [0x00118] in <69945a8ed6c540cf90b578de735e0605>:0 
 at Verse.AI.JobDriver.DriverTick () [0x00163] in <69945a8ed6c540cf90b578de735e0605>:0  
(Filename: C:\buildslave\unity\build\Runtime/Export/Debug/Debug.bindings.h Line: 39)

Complete the following checklist
I hereby verify that I have done the following:

• Confirmed that my game version and load order are correct.
• Confirmed that I am running the appropriate and most updated version of Combat Extended and required compatibility patches.
• Confirmed I am not running any mods with known incompatibilities with Combat Extended.
• Disabled Combat Extended and attempted to reproduce the behavior without success. (vanilla doesn't have riposte mechanic at all, what else could I expect?)

[masakitenchi]

Dunno if post ludeon source is legal, but
The stacktrace suggests that the exception is thrown at here:

IL_02A7: ldarg.0
IL_02A8: callvirt   virtual Verse.Pawn Verse.Verb::get_CasterPawn()
IL_02AD: ldfld      Verse.Pawn_StanceTracker Verse.Pawn::stances
IL_02B2: ldarg.0
IL_02B3: ldfld      Verse.VerbProperties Verse.Verb::verbProps
IL_02B8: ldarg.0
IL_02B9: ldarg.0
IL_02BA: callvirt   virtual Verse.Pawn Verse.Verb::get_CasterPawn()
IL_02BF: callvirt   System.Int32 Verse.VerbProperties::AdjustedCooldownTicks(Verse.Verb ownerVerb, Verse.Pawn attacker)
IL_02C4: ldarg.0
IL_02C5: ldfld      Verse.LocalTargetInfo Verse.Verb::currentTarget
IL_02CA: ldarg.0
IL_02CB: newobj     System.Void Verse.Stance_Cooldown::.ctor(System.Int32 ticks, Verse.LocalTargetInfo focusTarg, Verse.Verb verb)
IL_02D0: callvirt   System.Void Verse.Pawn_StanceTracker::SetStance(Verse.Stance newStance)  <= Specifically here

so my conclusion is that Verse.Pawn_StanceTracker is null when game tries to call it, hence the NRE is thrown

[masakitenchi]

further investigation found a transpiler that tries to solve this
https://github.com/CombatExtended-Continued/CombatExtended/blob/Development/Source/CombatExtended/Harmony/Harmony_Verb.cs#L61C1-L62C1
but it seems to do little