From 5fd606ead34a9e02811aaee9a27492dd4b703f8b Mon Sep 17 00:00:00 2001
From: Lactozilla <jp6781615@gmail.com>
Date: Fri, 13 Dec 2024 15:18:27 -0300
Subject: [PATCH] Fix #1324

---
 src/d_think.h          |  2 ++
 src/f_finale.c         |  2 +-
 src/g_demo.c           |  4 ++--
 src/g_game.c           |  2 +-
 src/lua_script.c       |  4 ++--
 src/m_cheat.c          |  4 ++--
 src/m_perfstats.c      |  2 +-
 src/netcode/d_clisrv.c |  2 +-
 src/p_enemy.c          | 14 +++++++-------
 src/p_inter.c          | 16 ++++++++--------
 src/p_mobj.c           | 21 ++++++++++-----------
 src/p_polyobj.c        |  2 +-
 src/p_saveg.c          | 13 ++++++-------
 src/p_setup.c          |  6 +++---
 src/p_spec.c           |  8 ++++----
 src/p_tick.c           |  5 +++--
 src/p_user.c           | 38 +++++++++++++++++++-------------------
 src/st_stuff.c         |  2 +-
 18 files changed, 74 insertions(+), 73 deletions(-)

diff --git a/src/d_think.h b/src/d_think.h
index 589124587..76c1bb5b8 100644
--- a/src/d_think.h
+++ b/src/d_think.h
@@ -51,6 +51,8 @@ typedef struct thinker_s
 	// killough 11/98: count of how many other objects reference
 	// this one using pointers. Used for garbage collection.
 	INT32 references;
+
+	boolean removing;
 	boolean cachable;
 
 #ifdef PARANOIA
diff --git a/src/f_finale.c b/src/f_finale.c
index 37e4ba070..a992a0dfd 100644
--- a/src/f_finale.c
+++ b/src/f_finale.c
@@ -3435,7 +3435,7 @@ void F_TitleScreenTicker(boolean run)
 		{
 			for (th = thlist[THINK_MOBJ].next; th != &thlist[THINK_MOBJ]; th = th->next)
 			{
-				if (th->function.acp1 == (actionf_p1)P_RemoveThinkerDelayed)
+				if (th->removing)
 					continue;
 
 				mo2 = (mobj_t *)th;
diff --git a/src/g_demo.c b/src/g_demo.c
index b0e16adda..8315e716b 100644
--- a/src/g_demo.c
+++ b/src/g_demo.c
@@ -614,7 +614,7 @@ void G_ConsGhostTic(void)
 				mobj = NULL;
 				for (th = thlist[THINK_MOBJ].next; th != &thlist[THINK_MOBJ]; th = th->next)
 				{
-					if (th->function.acp1 == (actionf_p1)P_RemoveThinkerDelayed)
+					if (th->removing)
 						continue;
 					mobj = (mobj_t *)th;
 					if (mobj->type == (mobjtype_t)type && mobj->x == x && mobj->y == y && mobj->z == z)
@@ -2696,7 +2696,7 @@ void G_DoPlayMetal(void)
 	// find metal sonic
 	for (th = thlist[THINK_MOBJ].next; th != &thlist[THINK_MOBJ]; th = th->next)
 	{
-		if (th->function.acp1 == (actionf_p1)P_RemoveThinkerDelayed)
+		if (th->removing)
 			continue;
 
 		mo = (mobj_t *)th;
diff --git a/src/g_game.c b/src/g_game.c
index d409bb2cf..175e757ec 100644
--- a/src/g_game.c
+++ b/src/g_game.c
@@ -3072,7 +3072,7 @@ void G_ChangePlayerReferences(mobj_t *oldmo, mobj_t *newmo)
 	// scan all thinkers
 	for (th = thlist[THINK_MOBJ].next; th != &thlist[THINK_MOBJ]; th = th->next)
 	{
-		if (th->function.acp1 == (actionf_p1)P_RemoveThinkerDelayed)
+		if (th->removing)
 			continue;
 
 		mo2 = (mobj_t *)th;
diff --git a/src/lua_script.c b/src/lua_script.c
index 623d88673..686555a16 100644
--- a/src/lua_script.c
+++ b/src/lua_script.c
@@ -1779,7 +1779,7 @@ void LUA_Archive(save_t *save_p)
 
 	for (th = thlist[THINK_MOBJ].next; th != &thlist[THINK_MOBJ]; th = th->next)
 	{
-		if (th->function.acp1 == (actionf_p1)P_RemoveThinkerDelayed)
+		if (th->removing)
 			continue;
 
 		// archive function will determine when to skip mobjs,
@@ -1817,7 +1817,7 @@ void LUA_UnArchive(save_t *save_p)
 		mobjnum = P_ReadUINT32(save_p); // read a mobjnum
 		for (th = thlist[THINK_MOBJ].next; th != &thlist[THINK_MOBJ]; th = th->next)
 		{
-			if (th->function.acp1 == (actionf_p1)P_RemoveThinkerDelayed)
+			if (th->removing)
 				continue;
 			if (((mobj_t *)th)->mobjnum != mobjnum) // find matching mobj
 				continue;
diff --git a/src/m_cheat.c b/src/m_cheat.c
index 2b32253fa..4be071bb2 100644
--- a/src/m_cheat.c
+++ b/src/m_cheat.c
@@ -562,7 +562,7 @@ void Command_Teleport_f(void)
 
 			for (th = thlist[THINK_MOBJ].next; th != &thlist[THINK_MOBJ]; th = th->next)
 			{
-				if (th->function.acp1 == (actionf_p1)P_RemoveThinkerDelayed)
+				if (th->removing)
 					continue;
 
 				mo2 = (mobj_t *)th;
@@ -1072,7 +1072,7 @@ static mapthing_t *OP_CreateNewMapThing(player_t *player, UINT16 type, boolean c
 
 		for (th = thlist[THINK_MOBJ].next; th != &thlist[THINK_MOBJ]; th = th->next)
 		{
-			if (th->function.acp1 == (actionf_p1)P_RemoveThinkerDelayed)
+			if (th->removing)
 				continue;
 
 			mo = (mobj_t *)th;
diff --git a/src/m_perfstats.c b/src/m_perfstats.c
index b9948bdc0..0a52b0125 100644
--- a/src/m_perfstats.c
+++ b/src/m_perfstats.c
@@ -584,7 +584,7 @@ static void PS_CountThinkers(void)
 		for (thinker = thlist[i].next; thinker != &thlist[i]; thinker = thinker->next)
 		{
 			ps_thinkercount.value.i++;
-			if (thinker->function.acp1 == (actionf_p1)P_RemoveThinkerDelayed)
+			if (thinker->removing)
 				ps_removecount.value.i++;
 			else if (i == THINK_POLYOBJ)
 				ps_polythcount.value.i++;
diff --git a/src/netcode/d_clisrv.c b/src/netcode/d_clisrv.c
index d34dbc4e0..591923571 100644
--- a/src/netcode/d_clisrv.c
+++ b/src/netcode/d_clisrv.c
@@ -1814,7 +1814,7 @@ INT16 Consistancy(void)
 	{
 		for (th = thlist[THINK_MOBJ].next; th != &thlist[THINK_MOBJ]; th = th->next)
 		{
-			if (th->function.acp1 == (actionf_p1)P_RemoveThinkerDelayed)
+			if (th->removing)
 				continue;
 
 			mo = (mobj_t *)th;
diff --git a/src/p_enemy.c b/src/p_enemy.c
index 59ca95409..60cffebfc 100644
--- a/src/p_enemy.c
+++ b/src/p_enemy.c
@@ -3744,7 +3744,7 @@ static void P_DoBossVictory(mobj_t *mo)
 	// scan the remaining thinkers to see if all bosses are dead
 	for (th = thlist[THINK_MOBJ].next; th != &thlist[THINK_MOBJ]; th = th->next)
 	{
-		if (th->function.acp1 == (actionf_p1)P_RemoveThinkerDelayed)
+		if (th->removing)
 			continue;
 
 		mo2 = (mobj_t *)th;
@@ -6449,7 +6449,7 @@ void A_RingExplode(mobj_t *actor)
 
 	for (th = thlist[THINK_MOBJ].next; th != &thlist[THINK_MOBJ]; th = th->next)
 	{
-		if (th->function.acp1 == (actionf_p1)P_RemoveThinkerDelayed)
+		if (th->removing)
 			continue;
 
 		mo2 = (mobj_t *)th;
@@ -8756,7 +8756,7 @@ void A_FindTarget(mobj_t *actor)
 	// scan the thinkers
 	for (th = thlist[THINK_MOBJ].next; th != &thlist[THINK_MOBJ]; th = th->next)
 	{
-		if (th->function.acp1 == (actionf_p1)P_RemoveThinkerDelayed)
+		if (th->removing)
 			continue;
 
 		mo2 = (mobj_t *)th;
@@ -8820,7 +8820,7 @@ void A_FindTracer(mobj_t *actor)
 	// scan the thinkers
 	for (th = thlist[THINK_MOBJ].next; th != &thlist[THINK_MOBJ]; th = th->next)
 	{
-		if (th->function.acp1 == (actionf_p1)P_RemoveThinkerDelayed)
+		if (th->removing)
 			continue;
 
 		mo2 = (mobj_t *)th;
@@ -9498,7 +9498,7 @@ void A_RemoteAction(mobj_t *actor)
 		// scan the thinkers
 		for (th = thlist[THINK_MOBJ].next; th != &thlist[THINK_MOBJ]; th = th->next)
 		{
-			if (th->function.acp1 == (actionf_p1)P_RemoveThinkerDelayed)
+			if (th->removing)
 				continue;
 
 			mo2 = (mobj_t *)th;
@@ -9761,7 +9761,7 @@ void A_SetObjectTypeState(mobj_t *actor)
 
 	for (th = thlist[THINK_MOBJ].next; th != &thlist[THINK_MOBJ]; th = th->next)
 	{
-		if (th->function.acp1 == (actionf_p1)P_RemoveThinkerDelayed)
+		if (th->removing)
 			continue;
 
 		mo2 = (mobj_t *)th;
@@ -10391,7 +10391,7 @@ void A_CheckThingCount(mobj_t *actor)
 
 	for (th = thlist[THINK_MOBJ].next; th != &thlist[THINK_MOBJ]; th = th->next)
 	{
-		if (th->function.acp1 == (actionf_p1)P_RemoveThinkerDelayed)
+		if (th->removing)
 			continue;
 
 		mo2 = (mobj_t *)th;
diff --git a/src/p_inter.c b/src/p_inter.c
index dc606a47e..0e63fea1b 100644
--- a/src/p_inter.c
+++ b/src/p_inter.c
@@ -101,7 +101,7 @@ void P_ClearStarPost(INT32 postnum)
 	// scan the thinkers
 	for (th = thlist[THINK_MOBJ].next; th != &thlist[THINK_MOBJ]; th = th->next)
 	{
-		if (th->function.acp1 == (actionf_p1)P_RemoveThinkerDelayed)
+		if (th->removing)
 			continue;
 
 		mo2 = (mobj_t *)th;
@@ -130,7 +130,7 @@ void P_ResetStarposts(void)
 
 	for (th = thlist[THINK_MOBJ].next; th != &thlist[THINK_MOBJ]; th = th->next)
 	{
-		if (th->function.acp1 == (actionf_p1)P_RemoveThinkerDelayed)
+		if (th->removing)
 			continue;
 
 		post = (mobj_t *)th;
@@ -1003,7 +1003,7 @@ void P_TouchSpecialThing(mobj_t *special, mobj_t *toucher, boolean heightcheck)
 						// scan the thinkers to find the corresponding anchorpoint
 						for (th = thlist[THINK_MOBJ].next; th != &thlist[THINK_MOBJ]; th = th->next)
 						{
-							if (th->function.acp1 == (actionf_p1)P_RemoveThinkerDelayed)
+							if (th->removing)
 								continue;
 
 							mo2 = (mobj_t *)th;
@@ -1097,7 +1097,7 @@ void P_TouchSpecialThing(mobj_t *special, mobj_t *toucher, boolean heightcheck)
 				// scan the remaining thinkers
 				for (th = thlist[THINK_MOBJ].next; th != &thlist[THINK_MOBJ]; th = th->next)
 				{
-					if (th->function.acp1 == (actionf_p1)P_RemoveThinkerDelayed)
+					if (th->removing)
 						continue;
 
 					mo2 = (mobj_t *)th;
@@ -1147,7 +1147,7 @@ void P_TouchSpecialThing(mobj_t *special, mobj_t *toucher, boolean heightcheck)
 				// in from the paraloop. Isn't this just so efficient?
 				for (th = thlist[THINK_MOBJ].next; th != &thlist[THINK_MOBJ]; th = th->next)
 				{
-					if (th->function.acp1 == (actionf_p1)P_RemoveThinkerDelayed)
+					if (th->removing)
 						continue;
 
 					mo2 = (mobj_t *)th;
@@ -1522,7 +1522,7 @@ void P_TouchSpecialThing(mobj_t *special, mobj_t *toucher, boolean heightcheck)
 				// scan the remaining thinkers to find koopa
 				for (th = thlist[THINK_MOBJ].next; th != &thlist[THINK_MOBJ]; th = th->next)
 				{
-					if (th->function.acp1 == (actionf_p1)P_RemoveThinkerDelayed)
+					if (th->removing)
 						continue;
 
 					mo2 = (mobj_t *)th;
@@ -2020,7 +2020,7 @@ void P_TouchStarPost(mobj_t *post, player_t *player, boolean snaptopost)
 
 		for (th = thlist[THINK_MOBJ].next; th != &thlist[THINK_MOBJ]; th = th->next)
 		{
-			if (th->function.acp1 == (actionf_p1)P_RemoveThinkerDelayed)
+			if (th->removing)
 				continue;
 
 			mo2 = (mobj_t *)th;
@@ -2870,7 +2870,7 @@ void P_KillMobj(mobj_t *target, mobj_t *inflictor, mobj_t *source, UINT8 damaget
 				// scan the thinkers to make sure all the old pinch dummies are gone on death
 				for (th = thlist[THINK_MOBJ].next; th != &thlist[THINK_MOBJ]; th = th->next)
 				{
-					if (th->function.acp1 == (actionf_p1)P_RemoveThinkerDelayed)
+					if (th->removing)
 						continue;
 
 					mo = (mobj_t *)th;
diff --git a/src/p_mobj.c b/src/p_mobj.c
index fb9e7d78e..488c3d617 100644
--- a/src/p_mobj.c
+++ b/src/p_mobj.c
@@ -765,7 +765,7 @@ void P_EmeraldManager(void)
 
 	for (think = thlist[THINK_MOBJ].next; think != &thlist[THINK_MOBJ]; think = think->next)
 	{
-		if (think->function.acp1 == (actionf_p1)P_RemoveThinkerDelayed)
+		if (think->removing)
 			continue;
 
 		mo = (mobj_t *)think;
@@ -3455,7 +3455,7 @@ void P_DestroyRobots(void)
 
 	for (think = thlist[THINK_MOBJ].next; think != &thlist[THINK_MOBJ]; think = think->next)
 	{
-		if (think->function.acp1 == (actionf_p1)P_RemoveThinkerDelayed)
+		if (think->removing)
 			continue;
 
 		mo = (mobj_t *)think;
@@ -4254,7 +4254,7 @@ static void P_Boss3Thinker(mobj_t *mobj)
 			// this can happen if the boss was hurt earlier than expected
 			for (th = thlist[THINK_MOBJ].next; th != &thlist[THINK_MOBJ]; th = th->next)
 			{
-				if (th->function.acp1 == (actionf_p1)P_RemoveThinkerDelayed)
+				if (th->removing)
 					continue;
 
 				mo2 = (mobj_t *)th;
@@ -5343,7 +5343,7 @@ static void P_Boss9Thinker(mobj_t *mobj)
 		// Build a hoop linked list of 'em!
 		for (th = thlist[THINK_MOBJ].next; th != &thlist[THINK_MOBJ]; th = th->next)
 		{
-			if (th->function.acp1 == (actionf_p1)P_RemoveThinkerDelayed)
+			if (th->removing)
 				continue;
 
 			mo2 = (mobj_t *)th;
@@ -6045,7 +6045,7 @@ mobj_t *P_GetClosestAxis(mobj_t *source)
 	// scan the thinkers to find the closest axis point
 	for (th = thlist[THINK_MOBJ].next; th != &thlist[THINK_MOBJ]; th = th->next)
 	{
-		if (th->function.acp1 == (actionf_p1)P_RemoveThinkerDelayed)
+		if (th->removing)
 			continue;
 
 		mo2 = (mobj_t *)th;
@@ -11183,17 +11183,16 @@ tic_t itemrespawntime[ITEMQUESIZE];
 size_t iquehead, iquetail;
 
 #ifdef PARANOIA
-#define SCRAMBLE_REMOVED // Force debug build to crash when Removed mobj is accessed
+#define SCRAMBLE_REMOVED // Force debug build to crash when a removed mobj is accessed
 #endif
 void P_RemoveMobj(mobj_t *mobj)
 {
 	I_Assert(mobj != NULL);
-	if (P_MobjWasRemoved(mobj))
-		return; // something already removing this mobj.
+	if (P_MobjWasRemoved(mobj) || mobj->thinker.removing)
+		return; // Something already removed or is removing this mobj.
 
-	mobj->thinker.function.acp1 = (actionf_p1)P_RemoveThinkerDelayed; // shh. no recursing.
+	mobj->thinker.removing = true; // Set earlier to avoid recursion.
 	LUA_HookMobj(mobj, MOBJ_HOOK(MobjRemoved));
-	mobj->thinker.function.acp1 = (actionf_p1)P_MobjThinker; // needed for P_UnsetThingPosition, etc. to work.
 
 	// Rings only, please!
 	if (mobj->spawnpoint &&
@@ -12863,7 +12862,7 @@ static boolean P_MapAlreadyHasStarPost(mobj_t *mobj)
 
 	for (th = thlist[THINK_MOBJ].next; th != &thlist[THINK_MOBJ]; th = th->next)
 	{
-		if (th->function.acp1 == (actionf_p1)P_RemoveThinkerDelayed)
+		if (th->removing)
 			continue;
 
 		mo2 = (mobj_t *)th;
diff --git a/src/p_polyobj.c b/src/p_polyobj.c
index 168fca61f..4833b5896 100644
--- a/src/p_polyobj.c
+++ b/src/p_polyobj.c
@@ -1316,7 +1316,7 @@ void Polyobj_InitLevel(void)
 	// the mobj_t pointers on a queue for use below.
 	for (th = thlist[THINK_MOBJ].next; th != &thlist[THINK_MOBJ]; th = th->next)
 	{
-		if (th->function.acp1 == (actionf_p1)P_RemoveThinkerDelayed)
+		if (th->removing)
 			continue;
 
 		mo = (mobj_t *)th;
diff --git a/src/p_saveg.c b/src/p_saveg.c
index e939cf8e3..650622f59 100644
--- a/src/p_saveg.c
+++ b/src/p_saveg.c
@@ -2972,8 +2972,7 @@ static void P_NetArchiveThinkers(save_t *save_p)
 		// save off the current thinkers
 		for (th = thlist[i].next; th != &thlist[i]; th = th->next)
 		{
-			if (!(th->function.acp1 == (actionf_p1)P_RemoveThinkerDelayed
-			 || th->function.acp1 == (actionf_p1)P_NullPrecipThinker))
+			if (!(th->removing || th->function.acp1 == (actionf_p1)P_NullPrecipThinker))
 				numsaved++;
 
 			if (th->function.acp1 == (actionf_p1)P_MobjThinker)
@@ -3186,7 +3185,7 @@ static void P_NetArchiveThinkers(save_t *save_p)
 			}
 #ifdef PARANOIA
 			else
-				I_Assert(th->function.acp1 == (actionf_p1)P_RemoveThinkerDelayed); // wait garbage collection
+				I_Assert(th->removing); // wait garbage collection
 #endif
 		}
 
@@ -3207,7 +3206,7 @@ mobj_t *P_FindNewPosition(UINT32 oldposition)
 
 	for (th = thlist[THINK_MOBJ].next; th != &thlist[THINK_MOBJ]; th = th->next)
 	{
-		if (th->function.acp1 == (actionf_p1)P_RemoveThinkerDelayed)
+		if (th->removing)
 			continue;
 
 		mobj = (mobj_t *)th;
@@ -4528,7 +4527,7 @@ static inline void P_FinishMobjs(void)
 	for (currentthinker = thlist[THINK_MOBJ].next; currentthinker != &thlist[THINK_MOBJ];
 		currentthinker = currentthinker->next)
 	{
-		if (currentthinker->function.acp1 == (actionf_p1)P_RemoveThinkerDelayed)
+		if (currentthinker->removing)
 			continue;
 
 		mobj = (mobj_t *)currentthinker;
@@ -4546,7 +4545,7 @@ static void P_RelinkPointers(void)
 	for (currentthinker = thlist[THINK_MOBJ].next; currentthinker != &thlist[THINK_MOBJ];
 		currentthinker = currentthinker->next)
 	{
-		if (currentthinker->function.acp1 == (actionf_p1)P_RemoveThinkerDelayed)
+		if (currentthinker->removing)
 			continue;
 
 		mobj = (mobj_t *)currentthinker;
@@ -5376,7 +5375,7 @@ void P_SaveNetGame(save_t *save_p, boolean resending)
 	// Assign the mobjnumber for pointer tracking
 	for (th = thlist[THINK_MOBJ].next; th != &thlist[THINK_MOBJ]; th = th->next)
 	{
-		if (th->function.acp1 == (actionf_p1)P_RemoveThinkerDelayed)
+		if (th->removing)
 			continue;
 
 		mobj = (mobj_t *)th;
diff --git a/src/p_setup.c b/src/p_setup.c
index 906195c18..93286219d 100644
--- a/src/p_setup.c
+++ b/src/p_setup.c
@@ -692,7 +692,7 @@ void P_ReloadRings(void)
 	// scan the thinkers to find rings/spheres/hoops to unset
 	for (th = thlist[THINK_MOBJ].next; th != &thlist[THINK_MOBJ]; th = th->next)
 	{
-		if (th->function.acp1 == (actionf_p1)P_RemoveThinkerDelayed)
+		if (th->removing)
 			continue;
 
 		mo = (mobj_t *)th;
@@ -750,7 +750,7 @@ void P_SwitchSpheresBonusMode(boolean bonustime)
 	// scan the thinkers to find spheres to switch
 	for (th = thlist[THINK_MOBJ].next; th != &thlist[THINK_MOBJ]; th = th->next)
 	{
-		if (th->function.acp1 == (actionf_p1)P_RemoveThinkerDelayed)
+		if (th->removing)
 			continue;
 
 		mo = (mobj_t *)th;
@@ -7333,7 +7333,7 @@ void P_RespawnThings(void)
 
 	for (think = thlist[THINK_MOBJ].next; think != &thlist[THINK_MOBJ]; think = think->next)
 	{
-		if (think->function.acp1 == (actionf_p1)P_RemoveThinkerDelayed)
+		if (think->removing)
 			continue;
 		P_RemoveMobj((mobj_t *)think);
 	}
diff --git a/src/p_spec.c b/src/p_spec.c
index 9b124f9af..d375d3e2f 100644
--- a/src/p_spec.c
+++ b/src/p_spec.c
@@ -3642,7 +3642,7 @@ static void P_ProcessLineSpecial(line_t *line, mobj_t *mo, sector_t *callsec)
 					if (mo2->type != MT_EGGTRAP)
 						continue;
 
-					if (mo2->thinker.function.acp1 == (actionf_p1)P_RemoveThinkerDelayed)
+					if (mo2->thinker.removing)
 						continue;
 
 					P_KillMobj(mo2, NULL, mo, 0);
@@ -3854,7 +3854,7 @@ void P_SetupSignExit(player_t *player)
 	// spin all signposts in the level then.
 	for (think = thlist[THINK_MOBJ].next; think != &thlist[THINK_MOBJ]; think = think->next)
 	{
-		if (think->function.acp1 == (actionf_p1)P_RemoveThinkerDelayed)
+		if (think->removing)
 			continue;
 
 		thing = (mobj_t *)think;
@@ -3892,7 +3892,7 @@ boolean P_IsFlagAtBase(mobjtype_t flag)
 
 	for (think = thlist[THINK_MOBJ].next; think != &thlist[THINK_MOBJ]; think = think->next)
 	{
-		if (think->function.acp1 == (actionf_p1)P_RemoveThinkerDelayed)
+		if (think->removing)
 			continue;
 
 		mo = (mobj_t *)think;
@@ -4395,7 +4395,7 @@ static void P_ProcessEggCapsule(player_t *player, sector_t *sector)
 	// The chimps are my friends.. heeheeheheehehee..... - LouisJM
 	for (th = thlist[THINK_MOBJ].next; th != &thlist[THINK_MOBJ]; th = th->next)
 	{
-		if (th->function.acp1 == (actionf_p1)P_RemoveThinkerDelayed)
+		if (th->removing)
 			continue;
 		mo2 = (mobj_t *)th;
 		if (mo2->type != MT_EGGTRAP)
diff --git a/src/p_tick.c b/src/p_tick.c
index 68de09138..db8688484 100644
--- a/src/p_tick.c
+++ b/src/p_tick.c
@@ -162,7 +162,7 @@ void Command_CountMobjs_f(void)
 
 			for (th = thlist[THINK_MOBJ].next; th != &thlist[THINK_MOBJ]; th = th->next)
 			{
-				if (th->function.acp1 == (actionf_p1)P_RemoveThinkerDelayed)
+				if (th->removing)
 					continue;
 
 				if (((mobj_t *)th)->type == i)
@@ -182,7 +182,7 @@ void Command_CountMobjs_f(void)
 
 		for (th = thlist[THINK_MOBJ].next; th != &thlist[THINK_MOBJ]; th = th->next)
 		{
-			if (th->function.acp1 == (actionf_p1)P_RemoveThinkerDelayed)
+			if (th->removing)
 				continue;
 
 			if (((mobj_t *)th)->type == i)
@@ -348,6 +348,7 @@ void P_RemoveThinkerDelayed(thinker_t *thinker)
 void P_RemoveThinker(thinker_t *thinker)
 {
 	LUA_InvalidateUserdata(thinker);
+	thinker->removing = true;
 	thinker->function.acp1 = (actionf_p1)P_RemoveThinkerDelayed;
 }
 
diff --git a/src/p_user.c b/src/p_user.c
index a2bae228b..3301987a2 100644
--- a/src/p_user.c
+++ b/src/p_user.c
@@ -435,7 +435,7 @@ UINT8 P_FindLowestMare(void)
 	// to find the egg capsule with the lowest mare
 	for (th = thlist[THINK_MOBJ].next; th != &thlist[THINK_MOBJ]; th = th->next)
 	{
-		if (th->function.acp1 == (actionf_p1)P_RemoveThinkerDelayed)
+		if (th->removing)
 			continue;
 
 		mo2 = (mobj_t *)th;
@@ -488,7 +488,7 @@ boolean P_TransferToNextMare(player_t *player)
 	// to find the closest axis point
 	for (th = thlist[THINK_MOBJ].next; th != &thlist[THINK_MOBJ]; th = th->next)
 	{
-		if (th->function.acp1 == (actionf_p1)P_RemoveThinkerDelayed)
+		if (th->removing)
 			continue;
 
 		mo2 = (mobj_t *)th;
@@ -539,7 +539,7 @@ static mobj_t *P_FindAxis(INT32 mare, INT32 axisnum)
 	// to find the closest axis point
 	for (th = thlist[THINK_MOBJ].next; th != &thlist[THINK_MOBJ]; th = th->next)
 	{
-		if (th->function.acp1 == (actionf_p1)P_RemoveThinkerDelayed)
+		if (th->removing)
 			continue;
 
 		mo2 = (mobj_t *)th;
@@ -574,7 +574,7 @@ static mobj_t *P_FindAxisTransfer(INT32 mare, INT32 axisnum, mobjtype_t type)
 	// to find the closest axis point
 	for (th = thlist[THINK_MOBJ].next; th != &thlist[THINK_MOBJ]; th = th->next)
 	{
-		if (th->function.acp1 == (actionf_p1)P_RemoveThinkerDelayed)
+		if (th->removing)
 			continue;
 
 		mo2 = (mobj_t *)th;
@@ -615,7 +615,7 @@ void P_TransferToAxis(player_t *player, INT32 axisnum)
 	// to find the closest axis point
 	for (th = thlist[THINK_MOBJ].next; th != &thlist[THINK_MOBJ]; th = th->next)
 	{
-		if (th->function.acp1 == (actionf_p1)P_RemoveThinkerDelayed)
+		if (th->removing)
 			continue;
 
 		mo2 = (mobj_t *)th;
@@ -716,7 +716,7 @@ static void P_DeNightserizePlayer(player_t *player)
 	// Check to see if the player should be killed.
 	for (th = thlist[THINK_MOBJ].next; th != &thlist[THINK_MOBJ]; th = th->next)
 	{
-		if (th->function.acp1 == (actionf_p1)P_RemoveThinkerDelayed)
+		if (th->removing)
 			continue;
 
 		mo2 = (mobj_t *)th;
@@ -1899,7 +1899,7 @@ void P_SpawnShieldOrb(player_t *player)
 	// blaze through the thinkers to see if an orb already exists!
 	for (th = thlist[THINK_MOBJ].next; th != &thlist[THINK_MOBJ]; th = th->next)
 	{
-		if (th->function.acp1 == (actionf_p1)P_RemoveThinkerDelayed)
+		if (th->removing)
 			continue;
 
 		shieldobj = (mobj_t *)th;
@@ -5112,7 +5112,7 @@ void P_Telekinesis(player_t *player, fixed_t thrust, fixed_t range)
 
 	for (th = thlist[THINK_MOBJ].next; th != &thlist[THINK_MOBJ]; th = th->next)
 	{
-		if (th->function.acp1 == (actionf_p1)P_RemoveThinkerDelayed)
+		if (th->removing)
 			continue;
 
 		mo2 = (mobj_t *)th;
@@ -6479,7 +6479,7 @@ static void P_NightsTransferPoints(player_t *player, fixed_t xspeed, fixed_t rad
 		// Find next waypoint
 		for (th = thlist[THINK_MOBJ].next; th != &thlist[THINK_MOBJ]; th = th->next)
 		{
-			if (th->function.acp1 == (actionf_p1)P_RemoveThinkerDelayed)
+			if (th->removing)
 				continue;
 
 			mo2 = (mobj_t *)th;
@@ -6515,7 +6515,7 @@ static void P_NightsTransferPoints(player_t *player, fixed_t xspeed, fixed_t rad
 		{
 			for (th = thlist[THINK_MOBJ].next; th != &thlist[THINK_MOBJ]; th = th->next)
 			{
-				if (th->function.acp1 == (actionf_p1)P_RemoveThinkerDelayed)
+				if (th->removing)
 					continue;
 
 				mo2 = (mobj_t *)th;
@@ -6544,7 +6544,7 @@ static void P_NightsTransferPoints(player_t *player, fixed_t xspeed, fixed_t rad
 		{
 			for (th = thlist[THINK_MOBJ].next; th != &thlist[THINK_MOBJ]; th = th->next)
 			{
-				if (th->function.acp1 == (actionf_p1)P_RemoveThinkerDelayed)
+				if (th->removing)
 					continue;
 
 				mo2 = (mobj_t *)th;
@@ -7276,7 +7276,7 @@ static void P_NiGHTSMovement(player_t *player)
 		// to find the closest axis point
 		for (th = thlist[THINK_MOBJ].next; th != &thlist[THINK_MOBJ]; th = th->next)
 		{
-			if (th->function.acp1 == (actionf_p1)P_RemoveThinkerDelayed)
+			if (th->removing)
 				continue;
 
 			mo2 = (mobj_t *)th;
@@ -8176,7 +8176,7 @@ void P_MovePlayer(player_t *player)
 
 			for (th = thlist[THINK_MOBJ].next; th != &thlist[THINK_MOBJ]; th = th->next)
 			{
-				if (th->function.acp1 == (actionf_p1)P_RemoveThinkerDelayed)
+				if (th->removing)
 					continue;
 
 				mo2 = (mobj_t *)th;
@@ -9161,7 +9161,7 @@ void P_NukeEnemies(mobj_t *inflictor, mobj_t *source, fixed_t radius)
 
 	for (think = thlist[THINK_MOBJ].next; think != &thlist[THINK_MOBJ]; think = think->next)
 	{
-		if (think->function.acp1 == (actionf_p1)P_RemoveThinkerDelayed)
+		if (think->removing)
 			continue;
 
 		mo = (mobj_t *)think;
@@ -9259,7 +9259,7 @@ mobj_t *P_LookForFocusTarget(player_t *player, mobj_t *exclude, SINT8 direction,
 
 	for (think = thlist[THINK_MOBJ].next; think != &thlist[THINK_MOBJ]; think = think->next)
 	{
-		if (think->function.acp1 == (actionf_p1)P_RemoveThinkerDelayed)
+		if (think->removing)
 			continue;
 
 		mo = (mobj_t *)think;
@@ -9378,7 +9378,7 @@ mobj_t *P_LookForEnemies(player_t *player, boolean nonenemies, boolean bullet)
 
 	for (think = thlist[THINK_MOBJ].next; think != &thlist[THINK_MOBJ]; think = think->next)
 	{
-		if (think->function.acp1 == (actionf_p1)P_RemoveThinkerDelayed)
+		if (think->removing)
 			continue;
 
 		mo = (mobj_t *)think;
@@ -9524,7 +9524,7 @@ void P_FindEmerald(void)
 	// to find all emeralds
 	for (th = thlist[THINK_MOBJ].next; th != &thlist[THINK_MOBJ]; th = th->next)
 	{
-		if (th->function.acp1 == (actionf_p1)P_RemoveThinkerDelayed)
+		if (th->removing)
 			continue;
 
 		mo2 = (mobj_t *)th;
@@ -10925,7 +10925,7 @@ static mobj_t *P_GetAxis(INT32 num)
 
 	for (th = thlist[THINK_MOBJ].next; th != &thlist[THINK_MOBJ]; th = th->next)
 	{
-		if (th->function.acp1 == (actionf_p1)P_RemoveThinkerDelayed)
+		if (th->removing)
 			continue;
 
 		mobj = (mobj_t *)th;
@@ -12007,7 +12007,7 @@ void P_PlayerThink(player_t *player)
 
 		for (th = thlist[THINK_MOBJ].next; th != &thlist[THINK_MOBJ]; th = th->next)
 		{
-			if (th->function.acp1 == (actionf_p1)P_RemoveThinkerDelayed)
+			if (th->removing)
 				continue;
 
 			mo2 = (mobj_t *)th;
diff --git a/src/st_stuff.c b/src/st_stuff.c
index a44771e4b..5bb3aa98c 100644
--- a/src/st_stuff.c
+++ b/src/st_stuff.c
@@ -2655,7 +2655,7 @@ static boolean ST_doItemFinderIconsAndSound(void)
 	// Scan thinkers to find emblem mobj with these ids
 	for (th = thlist[THINK_MOBJ].next; th != &thlist[THINK_MOBJ]; th = th->next)
 	{
-		if (th->function.acp1 == (actionf_p1)P_RemoveThinkerDelayed)
+		if (th->removing)
 			continue;
 
 		mo2 = (mobj_t *)th;