mistakes were made (#43957)

code/__DEFINES/components.dm

@@ -110,6 +110,7 @@
 
 // /atom/movable signals
 #define COMSIG_MOVABLE_PRE_MOVE "movable_pre_move"					//from base of atom/movable/Moved(): (/atom)
+	#define COMPONENT_MOVABLE_BLOCK_PRE_MOVE 1
 #define COMSIG_MOVABLE_MOVED "movable_moved"					//from base of atom/movable/Moved(): (/atom, dir)
 #define COMSIG_MOVABLE_CROSS "movable_cross"					//from base of atom/movable/Cross(): (/atom/movable)
 #define COMSIG_MOVABLE_CROSSED "movable_crossed"                //from base of atom/movable/Crossed(): (/atom/movable)

code/datums/components/tether.dm

@@ -0,0 +1,37 @@
+/datum/component/tether
+	dupe_mode = COMPONENT_DUPE_UNIQUE_PASSARGS
+	var/atom/tether_target
+	var/max_dist
+	var/tether_name
+
+/datum/component/tether/Initialize(atom/tether_target, max_dist = 4, tether_name)
+	if(!isliving(parent) || !istype(tether_target) || !tether_target.loc)
+		return COMPONENT_INCOMPATIBLE
+	src.tether_target = tether_target
+	src.max_dist = max_dist
+	if (ispath(tether_name, /atom))
+		var/atom/tmp = tether_name
+		src.tether_name = initial(tmp.name)
+	else
+		src.tether_name = tether_name
+	RegisterSignal(parent, list(COMSIG_MOVABLE_PRE_MOVE), .proc/checkTether)
+
+/datum/component/tether/proc/checkTether(mob/mover, newloc)
+	if (get_dist(mover,newloc) > max_dist)
+		to_chat(mover, "<span class='userdanger'>The [tether_name] runs out of slack and prevents you from moving!</span>")
+		return COMPONENT_MOVABLE_BLOCK_PRE_MOVE
+
+	var/atom/blocker
+	:out
+		for(var/turf/T in getline(tether_target,newloc))
+			if (T.density)
+				blocker = T
+				break out
+			for(var/a in T)
+				var/atom/A = a
+				if(A.density && A != mover && A != tether_target)
+					blocker = A
+					break out
+	if (blocker)
+		to_chat(mover, "<span class='userdanger'>The [tether_name] catches on [blocker] and prevents you from moving!</span>")
+		return COMPONENT_MOVABLE_BLOCK_PRE_MOVE

code/game/atoms_movable.dm

@@ -223,8 +223,10 @@
 	if(!newloc.Enter(src, src.loc))
 		return
 
+	if (SEND_SIGNAL(src, COMSIG_MOVABLE_PRE_MOVE, newloc) & COMPONENT_MOVABLE_BLOCK_PRE_MOVE)
+		return
+
 	// Past this is the point of no return
-	SEND_SIGNAL(src, COMSIG_MOVABLE_PRE_MOVE, newloc)
 	var/atom/oldloc = loc
 	var/area/oldarea = get_area(oldloc)
 	var/area/newarea = get_area(newloc)

code/modules/mob/living/simple_animal/hostile/venus_human_trap.dm

@@ -64,6 +64,7 @@
 	unsuitable_atmos_damage = 0
 	faction = list("hostile","vines","plants")
 	var/list/grasping = list()
+	var/list/tethers = list()
 	var/max_grasps = 4
 	var/grasp_chance = 20
 	var/grasp_pull_chance = 85
@@ -75,6 +76,8 @@
 		var/datum/beam/B = grasping[L]
 		if(B)
 			qdel(B)
+	for(var/datum/component/tether in tethers)
+		tether.RemoveComponent()
 	grasping = null
 	return ..()
 
@@ -96,24 +99,31 @@
 					step(L,get_dir(L,src)) //reel them in
 					L.Paralyze(60) //you can't get away now~
 
-		if(grasping.len < max_grasps)
+		if(length(grasping) < max_grasps)
 			grasping:
 				for(var/mob/living/L in view(grasp_range, src))
-					if(L == src || faction_check_mob(L) || (L in grasping) || L == target)
+					if(L == src || faction_check_mob(L) || L in grasping || L == target)
 						continue
-					for(var/t in getline(src,L))
-						for(var/a in t)
-							var/atom/A = a
-							if(A.density && A != L)
+					for(var/turf/T in getline(src,L))
+						if (T.density)
+							continue grasping
+						for(var/obj/O in T)
+							if(O.density)
 								continue grasping
 					if(prob(grasp_chance))
 						to_chat(L, "<span class='userdanger'>\The [src] has you entangled!</span>")
 						grasping[L] = Beam(L, "vine", time=INFINITY, maxdistance=5, beam_type=/obj/effect/ebeam/vine)
-
+						tethers += list(L.AddComponent(/datum/component/tether, src, grasp_range+1, /obj/effect/ebeam/vine), AddComponent(/datum/component/tether, L, grasp_range+1, /obj/effect/ebeam/vine))
 						break //only take 1 new victim per cycle
 
 
 /mob/living/simple_animal/hostile/venus_human_trap/OpenFire(atom/the_target)
+	for(var/turf/T in getline(src,target))
+		if (T.density)
+			return
+		for(var/obj/O in T)
+			if(O.density)
+				return
 	var/dist = get_dist(src,the_target)
 	Beam(the_target, "vine", time=dist*2, maxdistance=dist+2, beam_type=/obj/effect/ebeam/vine)
 	the_target.attack_animal(src)

tgstation.dme

@@ -379,6 +379,7 @@
 #include "code\datums\components\squeak.dm"
 #include "code\datums\components\stationloving.dm"
 #include "code\datums\components\swarming.dm"
+#include "code\datums\components\tether.dm"
 #include "code\datums\components\thermite.dm"
 #include "code\datums\components\uplink.dm"
 #include "code\datums\components\waddling.dm"