- Re-jigged DoJump() to not be recursive so that 0-tic A_Jump* loops are no longer

able to potentially blow up the stack.

SVN r3902 (scripting)

src/dobject.h

@@ -205,6 +205,7 @@ enum EObjectFlags
 	OF_JustSpawned		= 1 << 8,		// Thinker was spawned this tic
 	OF_SerialSuccess	= 1 << 9,		// For debugging Serialize() calls
 	OF_Sentinel			= 1 << 10,		// Object is serving as the sentinel in a ring list
+	OF_StateChanged		= 1 << 11,		// Used by A_Jump* functions to feed back to SetState()
 };
 
 template<class T> class TObjPtr;

src/p_mobj.cpp

@@ -482,8 +482,17 @@ bool AActor::SetState (FState *newstate, bool nofunction)
 		{
 			// Check whether the called action function resulted in destroying the actor
 			if (ObjectFlags & OF_EuthanizeMe)
+			{
 				return false;
 			}
+			if (ObjectFlags & OF_StateChanged)
+			{ // The action was an A_Jump-style function that wants to change the next state.
+				ObjectFlags &= ~OF_StateChanged;
+				newstate = state;
+				tics = 0;		 // make sure we loop and set the new state properly
+				continue;
+			}
+		}
 		newstate = newstate->GetNextState();
 	} while (tics == 0);
 

src/thingdef/thingdef_codeptr.cpp

@@ -610,7 +610,15 @@ static void DoJump(AActor *self, AActor *stateowner, FState *callingstate, FStat
 	}
 	else if (callingstate == self->state)
 	{
-		self->SetState(jumpto);
+		// Rather than using self->SetState(jumpto) to set the state,
+		// set the state directly. Since this function is only called by
+		// action functions, which are only called by SetState(), we
+		// know that somewhere above us in the stack, a SetState()
+		// call is waiting for us to return. We use the flag OF_StateChanged
+		// to cause it to bypass the normal next state mechanism and use
+		// the one we set here instead.
+		self->state = jumpto;
+		self->ObjectFlags |= OF_StateChanged;
 	}
 	else
 	{ // something went very wrong. This should never happen.