Experiment with replacing weakrefs in AI blackboard with deleting signals, ideally making it easier to work with and harder to cause hard deletes (#74791)

## About The Pull Request

Replaces weakref usage in AI blackboards with deleting signals

All blackboard var setting must go through setters rather than directly

## Why It's Good For The Game

This both makes it a ton easier to develop AI for, and also makes it
harder for hard deletes to sneak in, as has been seen with recent 515
prs showing hard deletes in AI blackboards

(To quantify "making it easier to develop AI", I found multiple bugs in
existing AI code due to the usage of weakrefs.)

I'm looking for `@Jacquerel` `@tralezab` 's opinions on the matter, also
maybe `@LemonInTheDark` if they're interested

## Changelog

🆑 Melbert
refactor: Mob ai refactored once again
/🆑

code/datums/ai/basic_mobs/basic_ai_behaviors/basic_attacking.dm

@@ -4,22 +4,22 @@
 
 /datum/ai_behavior/basic_melee_attack/setup(datum/ai_controller/controller, target_key, targetting_datum_key, hiding_location_key)
 	. = ..()
-	//Hiding location is priority
-	var/datum/weakref/weak_target = controller.blackboard[hiding_location_key] || controller.blackboard[target_key]
-	var/atom/target = weak_target?.resolve()
-	if(!target)
-		return FALSE
 	var/datum/targetting_datum/targetting_datum = controller.blackboard[targetting_datum_key]
-	if (!targetting_datum)
-		return
+	if(isnull(targetting_datum))
+		CRASH("No target datum was supplied in the blackboard for [controller.pawn]")
+
+	//Hiding location is priority
+	var/atom/target = controller.blackboard[hiding_location_key] || controller.blackboard[target_key]
+	if(QDELETED(target))
+		return FALSE
+
 	set_movement_target(controller, target)
 
 /datum/ai_behavior/basic_melee_attack/perform(seconds_per_tick, datum/ai_controller/controller, target_key, targetting_datum_key, hiding_location_key)
 	. = ..()
 	var/mob/living/basic/basic_mob = controller.pawn
 	//targetting datum will kill the action if not real anymore
-	var/datum/weakref/weak_target = controller.blackboard[target_key]
-	var/atom/target = weak_target?.resolve()
+	var/atom/target = controller.blackboard[target_key]
 	var/datum/targetting_datum/targetting_datum = controller.blackboard[targetting_datum_key]
 
 	if(!targetting_datum.can_attack(basic_mob, target))
@@ -28,7 +28,7 @@
 
 	var/hiding_target = targetting_datum.find_hidden_mobs(basic_mob, target) //If this is valid, theyre hidden in something!
 
-	controller.blackboard[hiding_location_key] = hiding_target
+	controller.set_blackboard_key(hiding_location_key, hiding_target)
 
 	if(hiding_target) //Slap it!
 		basic_mob.melee_attack(hiding_target)
@@ -39,7 +39,7 @@
 /datum/ai_behavior/basic_melee_attack/finish_action(datum/ai_controller/controller, succeeded, target_key, targetting_datum_key, hiding_location_key)
 	. = ..()
 	if(!succeeded)
-		controller.blackboard -= target_key
+		controller.clear_blackboard_key(target_key)
 
 /datum/ai_behavior/basic_melee_attack/average_speed
 	action_cooldown = 1 SECONDS
@@ -55,9 +55,8 @@
 
 /datum/ai_behavior/basic_ranged_attack/setup(datum/ai_controller/controller, target_key, targetting_datum_key, hiding_location_key)
 	. = ..()
-	var/datum/weakref/weak_target = controller.blackboard[hiding_location_key] || controller.blackboard[target_key]
-	var/atom/target = weak_target?.resolve()
-	if(!target)
+	var/atom/target = controller.blackboard[hiding_location_key] || controller.blackboard[target_key]
+	if(QDELETED(target))
 		return FALSE
 	set_movement_target(controller, target)
 
@@ -65,8 +64,7 @@
 	. = ..()
 	var/mob/living/basic/basic_mob = controller.pawn
 	//targetting datum will kill the action if not real anymore
-	var/datum/weakref/weak_target = controller.blackboard[target_key]
-	var/atom/target = weak_target?.resolve()
+	var/atom/target = controller.blackboard[target_key]
 	var/datum/targetting_datum/targetting_datum = controller.blackboard[targetting_datum_key]
 
 	if(!targetting_datum.can_attack(basic_mob, target))
@@ -80,7 +78,7 @@
 		finish_action(controller, FALSE, target_key)
 		return
 
-	controller.blackboard[hiding_location_key] = WEAKREF(hiding_target)
+	controller.set_blackboard_key(hiding_location_key, hiding_target)
 
 	if(shots>1)
 		var/atom/burst_target = final_target
@@ -94,4 +92,4 @@
 /datum/ai_behavior/basic_ranged_attack/finish_action(datum/ai_controller/controller, succeeded, target_key, targetting_datum_key, hiding_location_key)
 	. = ..()
 	if(!succeeded)
-		controller.blackboard -= target_key
+		controller.clear_blackboard_key(target_key)

code/datums/ai/basic_mobs/basic_ai_behaviors/pick_up_item.dm

@@ -7,18 +7,16 @@
 
 /datum/ai_behavior/pick_up_item/setup(datum/ai_controller/controller, target_key, storage_key)
 	. = ..()
-	var/datum/weakref/weak_target = controller.blackboard[target_key]
-	var/obj/item/target = weak_target?.resolve()
+	var/obj/item/target = controller.blackboard[target_key]
 	return isitem(target) && isturf(target.loc) && !target.anchored
 
 /datum/ai_behavior/pick_up_item/perform(seconds_per_tick, datum/ai_controller/controller, target_key, storage_key)
 	. = ..()
-	var/datum/weakref/weak_target = controller.blackboard[target_key]
-	var/obj/item/target = weak_target?.resolve()
-	if(!isturf(target?.loc)) // Someone picked it up or it got deleted
+	var/obj/item/target = controller.blackboard[target_key]
+	if(QDELETED(target) || !isturf(target.loc)) // Someone picked it up or it got deleted
 		finish_action(controller, FALSE, target_key)
 		return
-	if(!in_range(controller.pawn, target)) // It teleported
+	if(!controller.pawn.Adjacent(target)) // It teleported
 		finish_action(controller, FALSE, target_key)
 		return
 	pickup_item(controller, target, storage_key)
@@ -26,22 +24,21 @@
 
 /datum/ai_behavior/pick_up_item/finish_action(datum/ai_controller/controller, success, target_key, storage_key)
 	. = ..()
-	controller.blackboard[target_key] = null
+	controller.clear_blackboard_key(target_key)
 
 /datum/ai_behavior/pick_up_item/proc/pickup_item(datum/ai_controller/controller, obj/item/target, storage_key)
 	var/atom/pawn = controller.pawn
 	drop_existing_item(controller, storage_key)
 	pawn.visible_message(span_notice("[pawn] picks up [target]."))
 	target.forceMove(pawn)
-	controller.blackboard[storage_key] = WEAKREF(target)
+	controller.set_blackboard_key(storage_key, target)
 	return TRUE
 
 /datum/ai_behavior/pick_up_item/proc/drop_existing_item(datum/ai_controller/controller, storage_key)
-	var/datum/weakref/carried_ref = controller.blackboard[storage_key]
-	var/obj/item/carried_item = carried_ref?.resolve()
+	var/obj/item/carried_item = controller.blackboard[storage_key]
 	if(!carried_item)
 		return
-	controller.blackboard[storage_key] = null
+	controller.clear_blackboard_key(storage_key)
 	var/atom/pawn = controller.pawn
 	if(carried_item.loc != pawn)
 		return

code/datums/ai/basic_mobs/basic_ai_behaviors/run_away_from_target.dm

@@ -7,9 +7,8 @@
 	var/run_distance = 9
 
 /datum/ai_behavior/run_away_from_target/setup(datum/ai_controller/controller, target_key, hiding_location_key)
-	var/datum/weakref/weak_target = controller.blackboard[hiding_location_key] || controller.blackboard[target_key]
-	var/atom/target = weak_target?.resolve()
-	if(!target)
+	var/atom/target = controller.blackboard[hiding_location_key] || controller.blackboard[target_key]
+	if(QDELETED(target))
 		return FALSE
 	if(!plot_path_away_from(controller, target))
 		return FALSE
@@ -17,9 +16,8 @@
 
 /datum/ai_behavior/run_away_from_target/perform(seconds_per_tick, datum/ai_controller/controller, target_key, hiding_location_key)
 	. = ..()
-	var/datum/weakref/weak_target = controller.blackboard[hiding_location_key] || controller.blackboard[target_key]
-	var/atom/target = weak_target?.resolve()
-	var/escaped =  !target || !can_see(controller.pawn, target, run_distance) // If we can't see it we got away
+	var/atom/target = controller.blackboard[hiding_location_key] || controller.blackboard[target_key]
+	var/escaped =  QDELETED(target) || !can_see(controller.pawn, target, run_distance) // If we can't see it we got away
 	if (escaped)
 		finish_action(controller, succeeded = TRUE, target_key = target_key, hiding_location_key = hiding_location_key)
 		return
@@ -43,4 +41,4 @@
 
 /datum/ai_behavior/run_away_from_target/finish_action(datum/ai_controller/controller, succeeded, target_key, hiding_location_key)
 	. = ..()
-	controller.blackboard[target_key] = null
+	controller.clear_blackboard_key(target_key)

code/datums/ai/basic_mobs/basic_ai_behaviors/step_towards_turf.dm

@@ -11,13 +11,12 @@
 	var/step_distance = 3
 
 /datum/ai_behavior/step_towards_turf/setup(datum/ai_controller/controller, turf_key)
-	var/datum/weakref/weak_turf = controller.blackboard[turf_key]
-	var/turf/target_turf = weak_turf?.resolve()
-	if (!target_turf || target_turf.is_blocked_turf(exclude_mobs = TRUE))
+	var/turf/target_turf = controller.blackboard[turf_key]
+	if (QDELETED(target_turf) || target_turf.is_blocked_turf(exclude_mobs = TRUE))
 		target_turf = find_destination_turf(args)
 		if (!target_turf)
 			return FALSE
-		controller.blackboard[turf_key] = WEAKREF(target_turf)
+		controller.set_blackboard_key(turf_key, target_turf)
 
 	if (target_turf.z != controller.pawn.z)
 		return FALSE

code/datums/ai/basic_mobs/basic_ai_behaviors/stop_and_stare.dm

@@ -4,16 +4,14 @@
 
 /datum/ai_behavior/stop_and_stare/setup(datum/ai_controller/controller, target_key)
 	. = ..()
-	var/datum/weakref/weak_target = controller.blackboard[target_key]
-	var/atom/movable/target = weak_target?.resolve()
+	var/atom/movable/target = controller.blackboard[target_key]
 	return ismovable(target) && isturf(target.loc) && ismob(controller.pawn)
 
 /datum/ai_behavior/stop_and_stare/perform(seconds_per_tick, datum/ai_controller/controller, target_key)
 	// i don't really like doing this but we wanna make sure that the cooldown is pertinent to what we need for this specific controller before we invoke parent
 	action_cooldown = controller.blackboard[BB_STATIONARY_COOLDOWN]
 	. = ..()
-	var/datum/weakref/weak_target = controller.blackboard[target_key]
-	var/atom/movable/target = weak_target?.resolve()
+	var/atom/movable/target = controller.blackboard[target_key]
 	if(!ismovable(target) || !isturf(target.loc)) // just to make sure that nothing funky happened between setup and perform
 		return
 

code/datums/ai/basic_mobs/basic_ai_behaviors/targeted_mob_ability.dm

@@ -5,12 +5,9 @@
 /datum/ai_behavior/targeted_mob_ability
 
 /datum/ai_behavior/targeted_mob_ability/perform(seconds_per_tick, datum/ai_controller/controller, ability_key, target_key)
-	var/datum/weakref/weak_ability = controller.blackboard[ability_key]
-	var/datum/action/cooldown/ability = weak_ability?.resolve()
-
-	var/datum/weakref/weak_target = controller.blackboard[target_key]
-	var/mob/living/target = weak_target?.resolve()
-	if(!ability || QDELETED(target))
+	var/datum/action/cooldown/ability = controller.blackboard[ability_key]
+	var/mob/living/target = controller.blackboard[target_key]
+	if(QDELETED(ability) || QDELETED(target))
 		finish_action(controller, FALSE, ability_key, target_key)
 		return
 	var/mob/pawn = controller.pawn
@@ -19,16 +16,15 @@
 
 /datum/ai_behavior/targeted_mob_ability/finish_action(datum/ai_controller/controller, succeeded, ability_key, target_key)
 	. = ..()
-	var/datum/weakref/weak_target = controller.blackboard[target_key]
-	var/atom/target = weak_target?.resolve()
+	var/atom/target = controller.blackboard[target_key]
 	if (QDELETED(target))
-		controller.blackboard[target_key] = null
+		controller.clear_blackboard_key(target_key)
 		return
 	if (!isliving(target))
 		return
 	var/mob/living/living_target = target
 	if(living_target.stat >= UNCONSCIOUS)
-		controller.blackboard[target_key] = null
+		controller.clear_blackboard_key(target_key)
 
 /**
  * # Try Mob Ability and plan execute
@@ -38,7 +34,7 @@
 /datum/ai_behavior/targeted_mob_ability/and_plan_execute
 
 /datum/ai_behavior/targeted_mob_ability/and_plan_execute/finish_action(datum/ai_controller/controller, succeeded, ability_key, target_key)
-	controller.blackboard[BB_BASIC_MOB_EXECUTION_TARGET] = controller.blackboard[target_key]
+	controller.set_blackboard_key(BB_BASIC_MOB_EXECUTION_TARGET, controller.blackboard[target_key])
 	return ..()
 
 /**
@@ -49,4 +45,4 @@
 
 /datum/ai_behavior/targeted_mob_ability/and_clear_target/finish_action(datum/ai_controller/controller, succeeded, ability_key, target_key)
 	. = ..()
-	controller.blackboard[target_key] = null
+	controller.clear_blackboard_key(target_key)

code/datums/ai/basic_mobs/basic_ai_behaviors/targetting.dm

@@ -13,13 +13,12 @@
 	if(!targetting_datum)
 		CRASH("No target datum was supplied in the blackboard for [controller.pawn]")
 
-	var/datum/weakref/weak_target = controller.blackboard[target_key]
-	var/atom/current_target = weak_target?.resolve()
+	var/atom/current_target = controller.blackboard[target_key]
 	if (targetting_datum.can_attack(living_mob, current_target))
 		finish_action(controller, succeeded = FALSE)
 		return
 
-	controller.blackboard[target_key] = null
+	controller.clear_blackboard_key(target_key)
 	var/list/potential_targets = hearers(vision_range, controller.pawn) - living_mob //Remove self, so we don't suicide
 
 	for(var/HM in typecache_filter_list(range(vision_range, living_mob), hostile_machines)) //Can we see any hostile machines?
@@ -42,12 +41,12 @@
 		return
 
 	var/atom/target = pick_final_target(controller, filtered_targets)
-	controller.blackboard[target_key] = WEAKREF(target)
+	controller.set_blackboard_key(target_key, target)
 
 	var/atom/potential_hiding_location = targetting_datum.find_hidden_mobs(living_mob, target)
 
 	if(potential_hiding_location) //If they're hiding inside of something, we need to know so we can go for that instead initially.
-		controller.blackboard[hiding_location_key] = WEAKREF(potential_hiding_location)
+		controller.set_blackboard_key(hiding_location_key, potential_hiding_location)
 
 	finish_action(controller, succeeded = TRUE)
 

code/datums/ai/basic_mobs/basic_ai_behaviors/tipped_reaction.dm

@@ -33,5 +33,5 @@
 /datum/ai_behavior/tipped_reaction/finish_action(datum/ai_controller/controller, succeeded, tipper_key, reacting_key)
 	. = ..()
 	//I'VE SAID MY PEACE...
-	controller.blackboard[reacting_key] = FALSE
-	controller.blackboard[tipper_key] = null
+	controller.set_blackboard_key(reacting_key, FALSE)
+	controller.clear_blackboard_key(tipper_key)

code/datums/ai/basic_mobs/basic_ai_behaviors/travel_towards.dm

@@ -9,9 +9,8 @@
 
 /datum/ai_behavior/travel_towards/setup(datum/ai_controller/controller, target_key)
 	. = ..()
-	var/datum/weakref/weak_target = controller.blackboard[target_key]
-	var/atom/target = weak_target?.resolve()
-	if(isnull(target))
+	var/atom/target = controller.blackboard[target_key]
+	if(QDELETED(target))
 		return FALSE
 	set_movement_target(controller, target)
 

code/datums/ai/basic_mobs/basic_subtrees/attack_obstacle_in_path.dm

@@ -7,10 +7,8 @@
 
 /datum/ai_planning_subtree/attack_obstacle_in_path/SelectBehaviors(datum/ai_controller/controller, seconds_per_tick)
 	. = ..()
-	var/datum/weakref/weak_target = controller.blackboard[target_key]
-	var/atom/target = weak_target?.resolve()
-
-	if(isnull(target))
+	var/atom/target = controller.blackboard[target_key]
+	if(QDELETED(target))
 		return
 
 	var/turf/next_step = get_step_towards(controller.pawn, target)
@@ -31,10 +29,9 @@
 /datum/ai_behavior/attack_obstructions/perform(seconds_per_tick, datum/ai_controller/controller, target_key)
 	. = ..()
 	var/mob/living/basic/basic_mob = controller.pawn
-	var/datum/weakref/weak_target = controller.blackboard[target_key]
-	var/atom/target = weak_target?.resolve()
+	var/atom/target = controller.blackboard[target_key]
 
-	if (!target)
+	if (QDELETED(target))
 		finish_action(controller, succeeded = FALSE)
 		return
 

code/datums/ai/basic_mobs/basic_subtrees/find_food.dm

@@ -1,10 +1,11 @@
-/// similar to finding a target but looks for food types in the
+/// similar to finding a target but looks for food types in the // the what?
 /datum/ai_planning_subtree/find_food
 
 /datum/ai_planning_subtree/find_food/SelectBehaviors(datum/ai_controller/controller, seconds_per_tick)
 	. = ..()
 	var/atom/target = controller.blackboard[BB_BASIC_MOB_CURRENT_TARGET]
-	if(target && !QDELETED(target))
+	if(!QDELETED(target))
+		// Busy with something
 		return
-	var/list/wanted = controller.blackboard[BB_BASIC_FOODS]
-	controller.queue_behavior(/datum/ai_behavior/find_and_set/in_list, BB_BASIC_MOB_CURRENT_TARGET, wanted)
+
+	controller.queue_behavior(/datum/ai_behavior/find_and_set/in_list, BB_BASIC_MOB_CURRENT_TARGET, controller.blackboard[BB_BASIC_FOODS])

code/datums/ai/basic_mobs/basic_subtrees/flee_target.dm

@@ -11,9 +11,8 @@
 	. = ..()
 	if (!controller.blackboard[BB_BASIC_MOB_FLEEING])
 		return
-	var/datum/weakref/weak_target = controller.blackboard[target_key]
-	var/atom/target = weak_target?.resolve()
-	if(!target || QDELETED(target))
+	var/atom/target = controller.blackboard[target_key]
+	if(QDELETED(target))
 		return
 	controller.queue_behavior(flee_behaviour, target_key, hiding_place_key)
 	return SUBTREE_RETURN_FINISH_PLANNING //we gotta get out of here.

code/datums/ai/basic_mobs/basic_subtrees/simple_attack_target.dm

@@ -3,10 +3,8 @@
 
 /datum/ai_planning_subtree/basic_melee_attack_subtree/SelectBehaviors(datum/ai_controller/controller, seconds_per_tick)
 	. = ..()
-	var/datum/weakref/weak_target = controller.blackboard[BB_BASIC_MOB_CURRENT_TARGET]
-	var/atom/target = weak_target?.resolve()
-
-	if(!target || QDELETED(target))
+	var/atom/target = controller.blackboard[BB_BASIC_MOB_CURRENT_TARGET]
+	if(QDELETED(target))
 		return
 	controller.queue_behavior(melee_attack_behavior, BB_BASIC_MOB_CURRENT_TARGET, BB_TARGETTING_DATUM, BB_BASIC_MOB_CURRENT_TARGET_HIDING_LOCATION)
 	return SUBTREE_RETURN_FINISH_PLANNING //we are going into battle...no distractions.
@@ -20,9 +18,8 @@
 
 /datum/ai_planning_subtree/basic_ranged_attack_subtree/SelectBehaviors(datum/ai_controller/controller, seconds_per_tick)
 	. = ..()
-	var/datum/weakref/weak_target = controller.blackboard[BB_BASIC_MOB_CURRENT_TARGET]
-	var/atom/target = weak_target?.resolve()
-	if(!target || QDELETED(target))
+	var/atom/target = controller.blackboard[BB_BASIC_MOB_CURRENT_TARGET]
+	if(QDELETED(target))
 		return
 	controller.queue_behavior(ranged_attack_behavior, BB_BASIC_MOB_CURRENT_TARGET, BB_TARGETTING_DATUM, BB_BASIC_MOB_CURRENT_TARGET_HIDING_LOCATION)
 	return SUBTREE_RETURN_FINISH_PLANNING //we are going into battle...no distractions.

code/datums/ai/basic_mobs/basic_subtrees/sleep_with_no_target.dm

@@ -15,16 +15,15 @@
 	var/time_to_wait = 10
 
 /datum/ai_behavior/sleep_after_targetless_time/perform(seconds_per_tick, datum/ai_controller/controller, target_key)
-	var/datum/weakref/weak_target = controller.blackboard[target_key]
-	var/atom/target = weak_target?.resolve()
+	var/atom/target = controller.blackboard[target_key]
 	finish_action(controller, succeeded = !target, seconds_per_tick = seconds_per_tick)
 
 /datum/ai_behavior/sleep_after_targetless_time/finish_action(datum/ai_controller/controller, succeeded, seconds_per_tick)
 	. = ..()
 	if (!succeeded)
-		controller.blackboard[BB_TARGETLESS_TIME] = 0
+		controller.set_blackboard_key(BB_TARGETLESS_TIME, 0)
 		return
-	controller.blackboard[BB_TARGETLESS_TIME] += seconds_per_tick
+	controller.add_blackboard_key(BB_TARGETLESS_TIME, seconds_per_tick)
 	if (controller.blackboard[BB_TARGETLESS_TIME] > time_to_wait)
 		enter_sleep(controller)
 

code/datums/ai/basic_mobs/basic_subtrees/stare_at_thing.dm

@@ -2,8 +2,7 @@
 /datum/ai_planning_subtree/stare_at_thing
 
 /datum/ai_planning_subtree/stare_at_thing/SelectBehaviors(datum/ai_controller/controller, seconds_per_tick)
-	var/datum/weakref/weak_target = controller.blackboard[BB_STATIONARY_CAUSE]
-	var/atom/target = weak_target?.resolve()
+	var/atom/target = controller.blackboard[BB_STATIONARY_CAUSE]
 
 	if(isnull(target)) // No target? Time to locate one using the list we set in this mob's blackboard.
 		var/list/potential_scares = controller.blackboard[BB_STATIONARY_TARGETS]
@@ -11,4 +10,3 @@
 		return
 
 	controller.queue_behavior(/datum/ai_behavior/stop_and_stare, BB_STATIONARY_CAUSE)
-

code/datums/ai/basic_mobs/basic_subtrees/target_retaliate.dm

@@ -35,36 +35,22 @@
 	if(!targetting_datum)
 		CRASH("No target datum was supplied in the blackboard for [controller.pawn]")
 
-	var/list/enemy_refs = controller.blackboard[shitlist_key]
-	if (!length(enemy_refs))
-		finish_action(controller, succeeded = FALSE)
-		return
-
-	var/list/enemies_list = list()
-	for (var/datum/weakref/enemy_ref as anything in enemy_refs)
-		var/atom/enemy = enemy_ref.resolve()
-		if (!can_attack_target(living_mob, enemy, targetting_datum))
-			controller.blackboard[shitlist_key] -= enemy_ref
-			continue
-		enemies_list += enemy
-
+	var/list/enemies_list = controller.blackboard[shitlist_key]
 	if (!length(enemies_list))
 		finish_action(controller, succeeded = FALSE)
 		return
 
-	var/datum/weakref/weak_target = controller.blackboard[target_key]
-	var/atom/target = weak_target?.resolve()
-	if (target && (locate(target) in enemies_list)) // Don't bother changing
+	if (controller.blackboard[target_key] in enemies_list) // Don't bother changing
 		finish_action(controller, succeeded = FALSE)
 		return
 
 	var/atom/new_target = pick_final_target(controller, enemies_list)
-	controller.blackboard[target_key] = WEAKREF(new_target)
+	controller.set_blackboard_key(target_key, new_target)
 
 	var/atom/potential_hiding_location = targetting_datum.find_hidden_mobs(living_mob, new_target)
 
 	if(potential_hiding_location) //If they're hiding inside of something, we need to know so we can go for that instead initially.
-		controller.blackboard[hiding_location_key] = WEAKREF(potential_hiding_location)
+		controller.set_blackboard_key(hiding_location_key, potential_hiding_location)
 
 	finish_action(controller, succeeded = TRUE)
 

code/datums/ai/basic_mobs/basic_subtrees/targeted_mob_ability.dm

@@ -13,14 +13,9 @@
 	if (!ability_key)
 		CRASH("You forgot to tell this mob where to find its ability")
 
-	var/datum/weakref/weak_target = controller.blackboard[target_key]
-	var/mob/living/target = weak_target?.resolve()
-	if (QDELETED(target))
-		return
-
-	var/datum/weakref/weak_ability = controller.blackboard[ability_key]
-	var/datum/action/cooldown/using_action = weak_ability?.resolve()
-	if (!using_action || !using_action.IsAvailable())
+	var/mob/living/target = controller.blackboard[target_key]
+	var/datum/action/cooldown/using_action = controller.blackboard[ability_key]
+	if (QDELETED(target) || QDELETED(using_action) || !using_action.IsAvailable())
 		return
 
 	controller.queue_behavior(use_ability_behaviour, ability_key, target_key)

code/datums/ai/basic_mobs/basic_subtrees/use_mob_ability.dm

@@ -14,9 +14,8 @@
 	if (!ability_key)
 		CRASH("You forgot to tell this mob where to find its ability")
 
-	var/datum/weakref/weak_ability = controller.blackboard[ability_key]
-	var/datum/action/cooldown/using_action = weak_ability?.resolve()
-	if (!using_action || !using_action.IsAvailable())
+	var/datum/action/cooldown/using_action = controller.blackboard[ability_key]
+	if (QDELETED(using_action) || !using_action.IsAvailable())
 		return
 
 	controller.queue_behavior(use_ability_behaviour, ability_key)
@@ -26,9 +25,8 @@
 /datum/ai_behavior/use_mob_ability
 
 /datum/ai_behavior/use_mob_ability/perform(seconds_per_tick, datum/ai_controller/controller, ability_key)
-	var/datum/weakref/weak_ability = controller.blackboard[ability_key]
-	var/datum/action/cooldown/using_action = weak_ability?.resolve()
-	if (!using_action)
+	var/datum/action/cooldown/using_action = controller.blackboard[ability_key]
+	if (QDELETED(using_action))
 		finish_action(controller, FALSE, ability_key)
 		return
 	var/result = using_action.Trigger()

code/datums/ai/basic_mobs/pet_commands/fetch.dm

@@ -7,21 +7,18 @@
 
 /datum/ai_behavior/fetch_seek/setup(datum/ai_controller/controller, target_key, delivery_key)
 	. = ..()
-	var/datum/weakref/thing_ref = controller.blackboard[target_key]
-	var/obj/item/fetch_thing = thing_ref?.resolve()
-
+	var/obj/item/fetch_thing = controller.blackboard[target_key]
 	// It stopped existing
-	if (!fetch_thing)
+	if (QDELETED(fetch_thing))
 		return FALSE
 	set_movement_target(controller, fetch_thing)
 
 /datum/ai_behavior/fetch_seek/perform(seconds_per_tick, datum/ai_controller/controller, target_key, delivery_key)
 	. = ..()
-	var/datum/weakref/thing_ref = controller.blackboard[target_key]
-	var/obj/item/fetch_thing = thing_ref?.resolve()
+	var/obj/item/fetch_thing = controller.blackboard[target_key]
 
 	// It stopped existing
-	if (!fetch_thing)
+	if (QDELETED(fetch_thing))
 		finish_action(controller, FALSE, target_key, delivery_key)
 		return
 	var/mob/living/living_pawn = controller.pawn
@@ -37,12 +34,11 @@
 	if (success)
 		return
 	// Blacklist item if we failed
-	var/datum/weakref/thing_ref = controller.blackboard[target_key]
-	var/obj/item/target = thing_ref?.resolve()
+	var/obj/item/target = controller.blackboard[target_key]
 	if (target)
-		controller.blackboard[BB_FETCH_IGNORE_LIST][thing_ref] = TRUE
-	controller.blackboard[target_key] = null
-	controller.blackboard[delivery_key] = null
+		controller.set_blackboard_key_assoc_lazylist(BB_FETCH_IGNORE_LIST, target, TRUE)
+	controller.clear_blackboard_key(target_key)
+	controller.clear_blackboard_key(delivery_key)
 
 /**
  * The second half of fetching, deliver the item to a target.
@@ -52,17 +48,15 @@
 
 /datum/ai_behavior/deliver_fetched_item/setup(datum/ai_controller/controller, delivery_key, storage_key)
 	. = ..()
-	var/datum/weakref/return_ref = controller.blackboard[delivery_key]
-	var/mob/living/return_target = return_ref?.resolve()
-	if(!return_target) // Guess it's mine now
+	var/mob/living/return_target = controller.blackboard[delivery_key]
+	if(QDELETED(return_target)) // Guess it's mine now
 		return FALSE
 	set_movement_target(controller, return_target)
 
 /datum/ai_behavior/deliver_fetched_item/perform(seconds_per_tick, datum/ai_controller/controller, delivery_key, storage_key)
 	. = ..()
-	var/datum/weakref/return_ref = controller.blackboard[delivery_key]
-	var/mob/living/return_target = return_ref?.resolve()
-	if(!return_target)
+	var/mob/living/return_target = controller.blackboard[delivery_key]
+	if(QDELETED(return_target))
 		finish_action(controller, FALSE, delivery_key)
 		return
 
@@ -71,22 +65,21 @@
 
 /datum/ai_behavior/deliver_fetched_item/finish_action(datum/ai_controller/controller, success, delivery_key)
 	. = ..()
-	controller.blackboard[delivery_key] = null
-	controller.blackboard[BB_ACTIVE_PET_COMMAND] = null
+	controller.clear_blackboard_key(delivery_key)
+	controller.clear_blackboard_key(BB_ACTIVE_PET_COMMAND)
 
 /// Actually deliver the fetched item to the target, if we still have it
 /datum/ai_behavior/deliver_fetched_item/proc/deliver_item(datum/ai_controller/controller, return_target, storage_key)
 	var/mob/pawn = controller.pawn
-	var/datum/weakref/carried_ref = controller.blackboard[storage_key]
-	var/obj/item/carried_item = carried_ref?.resolve()
-	if(!carried_item || carried_item.loc != pawn)
+	var/obj/item/carried_item = controller.blackboard[storage_key]
+	if(QDELETED(carried_item) || carried_item.loc != pawn)
 		pawn.visible_message(span_notice("[pawn] looks around as if [pawn.p_they()] [pawn.p_have()] lost something."))
 		finish_action(controller, FALSE)
 		return
 
 	pawn.visible_message(span_notice("[pawn] delivers [carried_item] to [return_target]."))
 	carried_item.forceMove(get_turf(return_target))
-	controller.blackboard[storage_key] = null
+	controller.clear_blackboard_key(storage_key)
 	return TRUE
 
 /**
@@ -101,19 +94,15 @@
 
 /datum/ai_behavior/eat_fetched_snack/setup(datum/ai_controller/controller, target_key, delivery_key)
 	. = ..()
-	var/datum/weakref/thing_ref = controller.blackboard[target_key]
-	var/obj/item/snack = thing_ref?.resolve()
-
+	var/obj/item/snack = controller.blackboard[target_key]
 	if(!istype(snack) || !IS_EDIBLE(snack) || !(isturf(snack.loc) || ishuman(snack.loc)))
 		return FALSE // This isn't food at all!
 	set_movement_target(controller, snack)
 
 /datum/ai_behavior/eat_fetched_snack/perform(seconds_per_tick, datum/ai_controller/controller, target_key, delivery_key)
 	. = ..()
-	var/datum/weakref/thing_ref = controller.blackboard[target_key]
-	var/obj/item/snack = thing_ref?.resolve()
-
-	if(!(isturf(snack.loc) || ishuman(snack.loc)))
+	var/obj/item/snack = controller.blackboard[target_key]
+	if(QDELETED(snack) || !isturf(snack.loc) || ishuman(snack.loc))
 		finish_action(controller, FALSE) // Where did it go?
 
 	var/mob/living/basic/basic_pawn = controller.pawn
@@ -130,9 +119,9 @@
 
 /datum/ai_behavior/eat_fetched_snack/finish_action(datum/ai_controller/controller, succeeded, target_key, delivery_key)
 	. = ..()
-	controller.blackboard[target_key] = null
-	controller.blackboard[delivery_key] = null
-	controller.blackboard[BB_ACTIVE_PET_COMMAND] = null
+	controller.clear_blackboard_key(target_key)
+	controller.clear_blackboard_key(delivery_key)
+	controller.clear_blackboard_key(BB_ACTIVE_PET_COMMAND)
 
 /**
  * Clear our failed fetch list every so often
@@ -153,5 +142,5 @@
 /datum/ai_behavior/forget_failed_fetches/perform(seconds_per_tick, datum/ai_controller/controller)
 	. = ..()
 	COOLDOWN_START(src, reset_ignore_cooldown, cooldown_duration)
-	controller.blackboard[BB_FETCH_IGNORE_LIST] = list()
+	controller.clear_blackboard_key(BB_FETCH_IGNORE_LIST)
 	finish_action(controller, TRUE)

code/datums/ai/basic_mobs/pet_commands/pet_command_planning.dm

@@ -8,8 +8,7 @@
 /datum/ai_planning_subtree/pet_planning
 
 /datum/ai_planning_subtree/pet_planning/SelectBehaviors(datum/ai_controller/controller, seconds_per_tick)
-	var/datum/weakref/weak_command = controller.blackboard[BB_ACTIVE_PET_COMMAND]
-	var/datum/pet_command/command = weak_command?.resolve()
+	var/datum/pet_command/command = controller.blackboard[BB_ACTIVE_PET_COMMAND]
 	if (!command)
 		return // Do something else
 	return command.execute_action(controller)

code/datums/ai/basic_mobs/pet_commands/pet_follow_friend.dm

@@ -4,16 +4,14 @@
 
 /datum/ai_behavior/pet_follow_friend/setup(datum/ai_controller/controller, target_key)
 	. = ..()
-	var/datum/weakref/weak_target = controller.blackboard[target_key]
-	var/atom/target = weak_target?.resolve()
-	if (!target)
+	var/atom/target = controller.blackboard[target_key]
+	if (QDELETED(target))
 		return FALSE
 	set_movement_target(controller, target)
 
 /datum/ai_behavior/pet_follow_friend/perform(seconds_per_tick, datum/ai_controller/controller, target_key)
 	. = ..()
-	var/datum/weakref/weak_target = controller.blackboard[target_key]
-	var/atom/target = weak_target?.resolve()
-	if (!target)
+	var/atom/target = controller.blackboard[target_key]
+	if (QDELETED(target))
 		finish_action(controller, FALSE, target_key)
 		return

code/datums/ai/basic_mobs/pet_commands/pet_use_targetted_ability.dm

@@ -4,17 +4,15 @@
 
 /datum/ai_behavior/pet_use_ability/setup(datum/ai_controller/controller, ability_key, target_key)
 	. = ..()
-	var/datum/weakref/weak_target = controller.blackboard[target_key]
-	var/mob/living/target = weak_target?.resolve()
+	var/mob/living/target = controller.blackboard[target_key]
 	if (QDELETED(target))
 		return FALSE
 	set_movement_target(controller, target)
 
 /datum/ai_behavior/pet_use_ability/perform(seconds_per_tick, datum/ai_controller/controller, ability_key, target_key)
 	var/datum/action/cooldown/mob_cooldown/ability = controller.blackboard[ability_key]
-	var/datum/weakref/weak_target = controller.blackboard[target_key]
-	var/mob/living/target = weak_target?.resolve()
-	if (!ability || QDELETED(target))
+	var/mob/living/target = controller.blackboard[target_key]
+	if (QDELETED(ability) || QDELETED(target))
 		finish_action(controller, FALSE, ability_key, target_key)
 		return
 	var/mob/pawn = controller.pawn
@@ -23,4 +21,4 @@
 
 /datum/ai_behavior/pet_use_ability/finish_action(datum/ai_controller/controller, succeeded, ability_key, target_key)
 	. = ..()
-	controller.blackboard[target_key] = null
+	controller.clear_blackboard_key(target_key)

code/datums/ai/basic_mobs/pet_commands/play_dead.dm

@@ -21,4 +21,4 @@
 		return
 	basic_pawn.visible_message(span_notice("[basic_pawn] miraculously springs back to life!"))
 	basic_pawn.look_alive()
-	controller.blackboard[BB_ACTIVE_PET_COMMAND] = null
+	controller.clear_blackboard_key(BB_ACTIVE_PET_COMMAND)

code/datums/ai/basic_mobs/targetting_datums/dont_target_friends.dm

@@ -30,11 +30,10 @@
 	if (!living_mob.ai_controller) // How did you get here?
 		return FALSE
 
-	var/list/friends_list = living_mob.ai_controller.blackboard[BB_FRIENDS_LIST]
-	if (!friends_list)
-		return TRUE // We don't have any friends, anything's fair game
-	if (!friends_list[WEAKREF(target)])
-		return TRUE // This is not our friend, fire at will
+	if (!(target in living_mob.ai_controller.blackboard[BB_FRIENDS_LIST]))
+		// We don't have any friends, anything's fair game
+		// OR This is not our friend, fire at will
+		return TRUE
 
 	return FALSE