Revert turf signal preservation + open_space tweaks

code/__DEFINES/_click.dm

@@ -39,7 +39,7 @@
 //Pixel coordinates in screen_loc format ("[tile_x]:[pixel_x],[tile_y]:[pixel_y]")
 #define SCREEN_LOC "screen-loc"
 
-//Click catcher e.g. /atom/moveable/screen/click_catcher
+//Click catcher e.g. /atom/movable/screen/click_catcher
 #define CLICK_CATCHER "click_catcher"
 #define CLICK_CATCHER_ADD_PARAM ";click_catcher=1"
 

code/__DEFINES/dcs/signals/atom/signals_turf.dm

@@ -1,14 +1,24 @@
-///from /turf/Entered
+/**
+ * From /turf/Entered(): (turf/entered_turf)
+ * NOTE: This will occur for all locs including during turf/ChangeTurf() once Initialize occurs (mapload may delay it)
+ */
 #define COMSIG_MOVABLE_TURF_ENTERED "movable_turf_entered"
 
-/// from base of turf/ChangeTurf(): (path, list/new_baseturfs, flags, list/post_change_callbacks).
-/// `post_change_callbacks` is a list that signal handlers can mutate to append `/datum/callback` objects.
-/// They will be called with the new turf after the turf has changed.
+/**
+ * From base of turf/ChangeTurf(): (path, list/new_baseturfs, flags, list/post_change_callbacks)
+ * `post_change_callbacks` is a list that signal handlers can mutate to append `/datum/callback` objects.
+ * They will be called with the new turf after the turf has changed (but the turf's Initialize may not have occured yet for mapload).
+ */
 #define COMSIG_PRE_TURF_CHANGE "pre_turf_change"
 
 #define COMSIG_TURF_ENTER "turf_enter"
 	#define COMPONENT_TURF_ALLOW_MOVEMENT (1<<0)
 	#define COMPONENT_TURF_DENY_MOVEMENT  (1<<1)
+
+/**
+ * From /turf/Entered(): (atom/movable/entered_movable)
+ * NOTE: This cannot detect a turf/ChangeTurf() because signals are not retained during a ChangeTurf.
+ */
 #define COMSIG_TURF_ENTERED "turf_entered"
 
 /// Called when a bullet hits a turf

code/controllers/subsystem/hijack.dm

@@ -973,12 +973,9 @@ SUBSYSTEM_DEF(hijack)
 		target = target.ChangeTurf(make_current_walkable_type)
 		return target
 
-	// Make target open_space and chuck stuff down
+	// Make target open_space (which will chuck stuff down)
 	var/turf/open_space/space = target.ChangeTurf(/turf/open_space)
-	for(var/atom/movable/thing in space)
-		if(istype(thing, /obj/vis_contents_holder))
-			continue
-		space.check_fall(thing)
+
 	return space
 
 //~~~~~~~~~~~~~~~~~~~~~~~~ FTL STUFF ~~~~~~~~~~~~~~~~~~~~~~~~//

code/datums/components/weed_food.dm

@@ -87,7 +87,8 @@
 	parent_buckle = null
 
 /datum/component/weed_food/RegisterWithParent()
-	RegisterSignal(parent_mob, list(COMSIG_MOVABLE_MOVED, COMSIG_ATOM_AFTER_SHUTTLE_MOVE), PROC_REF(on_move))
+	// COMSIG_MOVABLE_TURF_ENTERED to handle movement and ChangeTurf
+	RegisterSignal(parent_mob, list(COMSIG_MOVABLE_TURF_ENTERED, COMSIG_ATOM_AFTER_SHUTTLE_MOVE), PROC_REF(on_move))
 	RegisterSignal(parent_mob, list(COMSIG_LIVING_REJUVENATED, COMSIG_HUMAN_REVIVED), PROC_REF(on_rejuv))
 	RegisterSignal(parent_mob, COMSIG_HUMAN_SET_UNDEFIBBABLE, PROC_REF(on_update))
 	RegisterSignal(parent_mob, COMSIG_LIVING_PREIGNITION, PROC_REF(on_preignition))
@@ -98,7 +99,7 @@
 /datum/component/weed_food/UnregisterFromParent()
 	if(parent_mob)
 		UnregisterSignal(parent_mob, list(
-			COMSIG_MOVABLE_MOVED,
+			COMSIG_MOVABLE_TURF_ENTERED,
 			COMSIG_ATOM_AFTER_SHUTTLE_MOVE,
 			COMSIG_LIVING_REJUVENATED,
 			COMSIG_HUMAN_REVIVED,
@@ -115,7 +116,7 @@
 		UnregisterSignal(parent_nest, COMSIG_PARENT_QDELETING)
 	UnregisterSignal(SSdcs, COMSIG_GLOB_GROUNDSIDE_FORSAKEN_HANDLING)
 
-/// SIGNAL_HANDLER for COMSIG_MOVABLE_MOVED and COMSIG_ATOM_AFTER_SHUTTLE_MOVE
+/// SIGNAL_HANDLER for COMSIG_MOVABLE_TURF_ENTERED and COMSIG_ATOM_AFTER_SHUTTLE_MOVE
 /datum/component/weed_food/proc/on_move()
 	SIGNAL_HANDLER
 

code/datums/datum.dm

@@ -130,14 +130,6 @@
 			debug_log("'[src]' datum_components was not null after removing all components! [length(datum_components)] entries remained...")
 			datum_components.Cut()
 
-	clear_signal_refs()
-	//END: ECS SHIT
-
-	return QDEL_HINT_QUEUE
-
-///Only override this if you know what you're doing. You do not know what you're doing
-///This is a threat
-/datum/proc/clear_signal_refs()
 	var/list/lookup = comp_lookup
 	if(lookup)
 		for(var/sig in lookup)
@@ -152,6 +144,9 @@
 
 	for(var/target in signal_procs)
 		UnregisterSignal(target, signal_procs[target])
+	//END: ECS SHIT
+
+	return QDEL_HINT_QUEUE
 
 /**
  * Callback called by a timer to end an associative-list-indexed cooldown.

code/game/machinery/telecomms/presets.dm

@@ -218,9 +218,19 @@ GLOBAL_LIST_EMPTY(all_static_telecomms_towers)
 	/// Holds the delay for when a cluster can recorrupt the comms tower after a pylon has been destroyed
 	COOLDOWN_DECLARE(corruption_delay)
 
-/obj/structure/machinery/telecomms/relay/preset/tower/mapcomms/Initialize()
+/obj/structure/machinery/telecomms/relay/preset/tower/mapcomms/Initialize(mapload, ...)
 	. = ..()
-	RegisterSignal(get_turf(src), COMSIG_WEEDNODE_GROWTH, PROC_REF(handle_xeno_acquisition))
+	// COMSIG_MOVABLE_TURF_ENTERED to handle ChangeTurf
+	RegisterSignal(src, COMSIG_MOVABLE_TURF_ENTERED, PROC_REF(register_with_turf))
+	if(!mapload)
+		register_with_turf()
+
+/// Handler for callback of COMSIG_MOVABLE_TURF_ENTERED (turf changed)
+/obj/structure/machinery/telecomms/relay/preset/tower/mapcomms/proc/register_with_turf(atom/movable/source, turf/new_turf)
+	SIGNAL_HANDLER
+	var/turf/location = get_turf(src)
+	if(location && (!new_turf || location == new_turf)) // We only need to monitor our loc not our locs
+		RegisterSignal(location, COMSIG_WEEDNODE_GROWTH, PROC_REF(handle_xeno_acquisition))
 
 /obj/structure/machinery/telecomms/relay/preset/tower/mapcomms/get_examine_text(mob/user)
 	. = ..()

code/game/objects/structures/multiz_stairs.dm

@@ -5,7 +5,10 @@
 
 /obj/structure/stairs/multiz/Initialize(mapload, ...)
 	. = ..()
-	RegisterSignal(loc, COMSIG_TURF_ENTERED, PROC_REF(on_turf_entered))
+	// COMSIG_MOVABLE_TURF_ENTERED to handle ChangeTurf
+	RegisterSignal(src, COMSIG_MOVABLE_TURF_ENTERED, PROC_REF(register_with_turf))
+	if(!mapload)
+		register_with_turf()
 	for(var/turf/blocked_turf in range(1, src))
 		blockers += WEAKREF(new /obj/effect/build_blocker(blocked_turf, src))
 		blockers += WEAKREF(new /obj/structure/blocker/anti_cade(blocked_turf))
@@ -15,7 +18,12 @@
 	QDEL_LIST(blockers)
 	return ..()
 
-/obj/structure/stairs/multiz/proc/on_turf_entered(turf/source, atom/movable/enterer)
+/// Handler for callback of COMSIG_MOVABLE_TURF_ENTERED (turf changed)
+/obj/structure/stairs/multiz/proc/register_with_turf()
+	SIGNAL_HANDLER
+	RegisterSignal(loc, COMSIG_TURF_ENTERED, PROC_REF(on_stairs_moved))
+
+/obj/structure/stairs/multiz/proc/on_stairs_moved(turf/source, atom/movable/enterer)
 	SIGNAL_HANDLER
 	if(!istype(enterer, /mob))
 		return
@@ -143,8 +151,21 @@
 				LAZYADD(from_turf_to_images[from_turf], destination_turf_images[to_turf])
 				break // we found stairs that work, go on to the next turf
 		if(length(from_turf_to_images[from_turf]))
-			RegisterSignal(from_turf, COMSIG_TURF_ENTERED, PROC_REF(handle_entered), TRUE)
+			RegisterSignal(from_turf, COMSIG_TURF_ENTERED, PROC_REF(handle_entered), override=TRUE)
+			RegisterSignal(from_turf, COMSIG_PRE_TURF_CHANGE, PROC_REF(handle_pre_turf_change), override=TRUE)
+
+/// Handler for COMSIG_PRE_TURF_CHANGE to set post_change_callbacks
+/datum/staircase/proc/handle_pre_turf_change(turf/source, path, list/new_baseturfs, flags, list/post_change_callbacks)
+	SIGNAL_HANDLER
+	post_change_callbacks += CALLBACK(src, PROC_REF(re_register_from_turf_signals), source)
+
+/// Re-registers the COMSIG_TURF_ENTERED and COMSIG_PRE_TURF_CHANGE for handle_pre_turf_change
+/datum/staircase/proc/re_register_from_turf_signals(turf/new_turf)
+	SHOULD_NOT_SLEEP(TRUE)
+	RegisterSignal(new_turf, COMSIG_TURF_ENTERED, PROC_REF(handle_entered))
+	RegisterSignal(new_turf, COMSIG_PRE_TURF_CHANGE, PROC_REF(handle_pre_turf_change))
 
+/// Handles COMSIG_TURF_ENTERED for mobs that enters a from_turf to register handle_movement and handle_deleted
 /datum/staircase/proc/handle_entered(turf/originator, atom/what_did_it)
 	SIGNAL_HANDLER
 
@@ -161,7 +182,7 @@
 
 	in_range_mob += mover
 
-
+/// Handles COMSIG_MOVABLE_MOVED for mobs that were in a from_turf
 /datum/staircase/proc/handle_movement(mob/mover, old_loc, direction)
 	SIGNAL_HANDLER
 
@@ -180,6 +201,7 @@
 	in_range_mob -= mover
 	UnregisterSignal(mover, list(COMSIG_MOVABLE_MOVED, COMSIG_PARENT_QDELETING))
 
+/// Handles COMSIG_PARENT_QDELETING for mobs that were in a from_turf
 /datum/staircase/proc/handle_deleted(atom/updater)
 	SIGNAL_HANDLER
 

code/game/turfs/open_space.dm

@@ -16,7 +16,7 @@ GLOBAL_DATUM_INIT(openspace_backdrop_one_for_all, /atom/movable/openspace_backdr
 	plane = OPEN_SPACE_PLANE_START
 	is_weedable = NOT_WEEDABLE
 
-/turf/open_space/Initialize()
+/turf/open_space/Initialize(mapload, ...)
 	pass_flags = GLOB.pass_flags_cache[type]
 
 	if (isnull(pass_flags))
@@ -27,6 +27,21 @@ GLOBAL_DATUM_INIT(openspace_backdrop_one_for_all, /atom/movable/openspace_backdr
 		initialize_pass_flags()
 
 	ADD_TRAIT(src, TURF_Z_TRANSPARENT_TRAIT, TRAIT_SOURCE_INHERENT)
+
+	#if defined(UNIT_TESTS) || defined(TESTING)
+	// Assert when testing that this open_space is placed somewhere valid
+	if(!istype(get_area(src), /area/misc/testroom))
+		var/turf/below = get_turf_below()
+		while(istype(below, /turf/open_space))
+			below = SSmapping.get_turf_below(below)
+		if(!below)
+			stack_trace("[src] at [COORD(src)] falls through the world!")
+	#endif
+
+	// We don't call parent and this is important
+	for(var/atom/movable/thing in src)
+		Entered(thing)
+
 	return INITIALIZE_HINT_LATELOAD
 
 /turf/open_space/Enter(atom/movable/mover, atom/forget)
@@ -70,6 +85,15 @@ GLOBAL_DATUM_INIT(openspace_backdrop_one_for_all, /atom/movable/openspace_backdr
 		to_chat(user, SPAN_WARNING("It would be too dangerous to go that way."))
 		return
 
+	var/turf/below = get_turf_below()
+	while(istype(below, /turf/open_space))
+		below = SSmapping.get_turf_below(below)
+	if(!below)
+		to_chat(user, SPAN_WARNING("You can't go that way."))
+		return
+
+	user.visible_message(SPAN_WARNING("[user] starts climbing down."), SPAN_WARNING("You start climbing down."))
+
 	var/climb_down_time = 1 SECONDS
 	if(ishuman_strict(user))
 		climb_down_time = 2.5 SECONDS
@@ -80,8 +104,6 @@ GLOBAL_DATUM_INIT(openspace_backdrop_one_for_all, /atom/movable/openspace_backdr
 		else
 			climb_down_time = 1 SECONDS
 
-	user.visible_message(SPAN_WARNING("[user] starts climbing down."), SPAN_WARNING("You start climbing down."))
-
 	var/list/grabbed_things = list()
 	var/hands_full = FALSE
 	for(var/obj/item/in_hand in list(user.l_hand, user.r_hand))
@@ -101,15 +123,10 @@ GLOBAL_DATUM_INIT(openspace_backdrop_one_for_all, /atom/movable/openspace_backdr
 
 	user.visible_message(SPAN_WARNING("[user] climbs down."), SPAN_WARNING("You climb down."))
 
-	var/turf/below = get_turf_below()
-	while(istype(below, /turf/open_space))
-		below = SSmapping.get_turf_below(below)
-
 	user.forceMove(below)
 	for(var/atom/movable/thing as anything in grabbed_things) // grabbed things aren't moved to the tile immediately to: make the animation better, preserve the grab
 		thing.forceMove(below)
 	below.on_climb_down(user)
-	return
 
 /turf/open_space/proc/check_fall(atom/movable/movable, kill_if_blocked=TRUE)
 	if(movable.flags_atom & NO_ZFALL)
@@ -121,6 +138,9 @@ GLOBAL_DATUM_INIT(openspace_backdrop_one_for_all, /atom/movable/openspace_backdr
 		below = SSmapping.get_turf_below(below)
 		height++
 
+	if(!below)
+		return
+
 	movable.forceMove(below)
 	movable.onZImpact(below, height)
 

code/game/turfs/turf.dm

@@ -105,8 +105,9 @@
 	else
 		initialize_pass_flags()
 
-	for(var/atom/movable/AM in src)
-		Entered(AM)
+	// Be sure to do this if you don't call parent!
+	for(var/atom/movable/thing in src)
+		Entered(thing)
 
 	if(light_power && light_range)
 		update_light()
@@ -131,6 +132,7 @@
 	vis_flags = VIS_HIDE
 	mouse_opacity = MOUSE_OPACITY_TRANSPARENT
 	anchored = TRUE
+	flags_atom = NO_ZFALL
 
 /obj/vis_contents_holder/Initialize(mapload, vis, offset)
 	. = ..()
@@ -358,6 +360,10 @@
 	return TRUE //Nothing found to block so return success!
 
 /turf/Entered(atom/movable/A)
+	SHOULD_CALL_PARENT(TRUE)
+
+	..() // Shouldn't do anything but to satisfy lint
+
 	if(!istype(A))
 		return
 
@@ -458,13 +464,6 @@
 	created_baseturf_lists[new_baseturfs[length(new_baseturfs)]] = new_baseturfs.Copy()
 	return new_baseturfs
 
-/// WARNING WARNING
-/// Turfs DO NOT lose their signals when they get replaced, REMEMBER THIS
-/// It's possible because turfs are fucked, and if you have one in a list and it's replaced with another one, the list ref points to the new turf
-/// We do it because moving signals over was needlessly expensive, and bloated a very commonly used bit of code
-/turf/clear_signal_refs()
-	return
-
 // Creates a new turf
 // new_baseturfs can be either a single type or list of types, formatted the same as baseturfs. see turf.dm
 /turf/proc/ChangeTurf(path, list/new_baseturfs, flags)
@@ -498,19 +497,8 @@
 
 	changing_turf = TRUE
 	qdel(src) //Just get the side effects and call Destroy
-	// Get signal registrations post-Destroy so stuff that's unregistered on Destroy won't be readded
-	var/list/old_comp_lookup = comp_lookup?.Copy()
-	var/list/old_signal_procs = signal_procs?.Copy()
 	var/turf/W = new path(src)
 
-	// WARNING WARNING
-	// Turfs DO NOT lose their signals when they get replaced, REMEMBER THIS
-	// It's possible because turfs are fucked, and if you have one in a list and it's replaced with another one, the list ref points to the new turf
-	if(old_comp_lookup)
-		LAZYOR(W.comp_lookup, old_comp_lookup)
-	if(old_signal_procs)
-		LAZYOR(W.signal_procs, old_signal_procs)
-
 	W.weak_reference = old_ref
 
 	for(var/datum/callback/callback as anything in post_change_callbacks)

code/game/turfs/walls/wall_types.dm

@@ -1286,7 +1286,10 @@
 		hivenumber = hive
 		set_hive_data(src, hive)
 	recalculate_structure()
-	update_tied_turf(loc)
+	if(!mapload)
+		update_tied_turf()
+	// COMSIG_MOVABLE_TURF_ENTERED to handle movement and ChangeTurf
+	RegisterSignal(src, COMSIG_MOVABLE_TURF_ENTERED, PROC_REF(update_tied_turf))
 	RegisterSignal(src, COMSIG_MOVABLE_XENO_START_PULLING, PROC_REF(allow_xeno_drag))
 	RegisterSignal(src, COMSIG_MOVABLE_PULLED, PROC_REF(continue_allowing_drag))
 
@@ -1397,20 +1400,17 @@
 
 	return ..()
 
-/obj/structure/alien/movable_wall/proc/update_tied_turf(turf/T)
-	SIGNAL_HANDLER
+/obj/structure/alien/movable_wall/proc/update_tied_turf()
+	SIGNAL_HANDLER // COMSIG_MOVABLE_TURF_ENTERED
 
-	if(!T)
+	if(!loc)
 		return
 
 	if(tied_turf)
-		UnregisterSignal(tied_turf, COMSIG_TURF_ENTER)
-	RegisterSignal(T, COMSIG_TURF_ENTER, PROC_REF(check_for_move))
-	tied_turf = T
+		UnregisterSignal(tied_turf, list(COMSIG_TURF_ENTER))
 
-/obj/structure/alien/movable_wall/forceMove(atom/dest)
-	. = ..()
-	update_tied_turf(loc)
+	tied_turf = loc
+	RegisterSignal(loc, COMSIG_TURF_ENTER, PROC_REF(check_for_move))
 
 /obj/structure/alien/movable_wall/proc/check_for_move(turf/T, atom/movable/mover)
 	if(group.next_push > world.time)