Revert "Revert "Multi-z infinite loop fixes (#30996)" (#31000)" (#31002)

This reverts commit 07e41392ef.

code/controllers/configuration.dm

@@ -76,6 +76,7 @@
 
 	
 	var/multiz_render_cap = 8			//how far down open spaces will render
+	var/multiz_bottom_cap = 16			//how far down open spaces will detect for a bottom
 
 	// BSQL things
 	var/bsql_debug = 0
@@ -583,6 +584,8 @@
 				
 				if("multiz_render_cap")
 					multiz_render_cap = text2num(value)
+				if("multiz_bottom_cap")
+					multiz_bottom_cap = text2num(value)
 
 				if("media_base_url")
 					media_base_url = value

code/modules/multiz/basic.dm

@@ -25,8 +25,12 @@
 /proc/GetConnectedZlevels(z)
 	. = list(z)
 	for(var/level = z, HasBelow(level), level = map.zLevels[level].z_below)
+		if((level != z) && (level in .)) // No infinite loops
+			break
 		. |= level
 	for(var/level = z, HasAbove(level), level = map.zLevels[level].z_above)
+		if((level != z) && (level in .)) // No infinite loops
+			break
 		. |= level
 
 /proc/AreConnectedZLevels(var/zA, var/zB)
@@ -38,8 +42,12 @@
 		return list()
 	. = list(turf.z)
 	for(var/level = turf.z, HasBelow(level) && isvisiblespace(GetBelow(locate(turf.x,turf.y,level))), level = map.zLevels[level].z_below)
+		if((level != turf.z) && (level in .)) // No infinite loops
+			break
 		. |= level
 	for(var/level = turf.z, HasAbove(level) && isvisiblespace(GetAbove(locate(turf.x,turf.y,level))), level = map.zLevels[level].z_above)
+		if((level != turf.z) && (level in .)) // No infinite loops
+			break
 		. |= level
 
 /proc/AreOpenConnectedZLevels(var/zA, var/zB)

code/modules/multiz/falling.dm

@@ -31,7 +31,11 @@
 		return
 
 	var/turf/bottom = null
+	var/depth = 0
 	for(bottom = GetBelow(src); isopenspace(bottom); bottom = GetBelow(bottom))
+		depth++
+		if(depth > config.multiz_bottom_cap) // To stop getting caught on this in infinite loops
+			break
 
 	if(istype(bottom,/turf/space))
 		return
@@ -64,7 +68,11 @@
 			return
 
 		bottom = null
+		depth = 0
 		for(bottom = GetBelow(src); isopenspace(bottom); bottom = GetBelow(bottom))
+			depth++
+			if(depth > config.multiz_bottom_cap) // To stop getting caught on this in infinite loops
+				break
 
 		if(istype(bottom,/turf/space))
 			return

config-example/config.txt

@@ -368,4 +368,7 @@ BSQL_THREAD_LIMIT 50
 #BSQL_DEBUG
 
 ## The maximum number of z-levels rendered above or below in multi-z
-MULTIZ_RENDER_CAP 8
+MULTIZ_RENDER_CAP 8
+
+## The maximum number of z-levels checked below in multi-z
+MULTIZ_BOTTOM_CAP 16