Code maintenace of Stats Entities (#4750)

# About the pull request

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 * Removes extraneous `= null`
 * Adds `Destroy` with proper clearing to all entities
 * Fixes up some single-letter vars and incorrect proc signatures
 * Transforms some comments to DMDoc
* Generally tries to clear up the usage of the entity lists (they're
MOSTLY indexed)

# Explain why it's good for the game
Code maintenance

# Testing Photographs and Procedure
Didn't see anything wrong but best tested in TM


# Changelog

Nothing player facing

code/datums/mind.dm

@@ -29,9 +29,14 @@
 	research_objective_interface = new()
 
 /datum/mind/Destroy()
+	QDEL_NULL(initial_account)
 	QDEL_NULL(objective_memory)
 	QDEL_NULL(objective_interface)
 	QDEL_NULL(research_objective_interface)
+	current = null
+	original = null
+	ghost_mob = null
+	player_entity = null
 	return ..()
 
 /datum/mind/proc/transfer_to(mob/living/new_character, force = FALSE)

code/datums/statistics/entities/caste_stats.dm

@@ -3,6 +3,10 @@
 	var/total_hits = 0
 	var/list/abilities_used = list() // types of /datum/entity/statistic, "tail sweep" = 10, "screech" = 2
 
+/datum/entity/player_stats/caste/Destroy(force)
+	. = ..()
+	QDEL_LIST_ASSOC_VAL(abilities_used)
+
 /datum/entity/player_stats/caste/proc/setup_ability(ability)
 	if(!ability)
 		return

code/datums/statistics/entities/death_stats.dm

@@ -140,16 +140,16 @@
 	new_death.detach()
 	return new_death
 
-/mob/living/carbon/human/track_mob_death(cause, cause_mob)
-	. = ..(cause, cause_mob, job)
+/mob/living/carbon/human/track_mob_death(datum/cause_data/cause_data, turf/death_loc)
+	. = ..()
 	if(statistic_exempt || !mind)
 		return
 	var/datum/entity/player_stats/human/human_stats = mind.setup_human_stats()
 	if(human_stats && human_stats.death_list)
 		human_stats.death_list.Insert(1, .)
 
-/mob/living/carbon/xenomorph/track_mob_death(cause, cause_mob)
-	var/datum/entity/statistic/death/new_death = ..(cause, cause_mob, caste_type)
+/mob/living/carbon/xenomorph/track_mob_death(datum/cause_data/cause_data, turf/death_loc)
+	var/datum/entity/statistic/death/new_death = ..()
 	if(!new_death)
 		return
 	new_death.is_xeno = TRUE // this was placed beneath the if below, which meant gibbing as a xeno wouldn't track properly in stats

code/datums/statistics/entities/human_stats.dm

@@ -5,10 +5,17 @@
 	var/total_shots = 0
 	var/total_shots_hit = 0
 	var/total_screams = 0
-	var/datum/entity/weapon_stats/top_weapon = null // reference to /datum/entity/weapon_stats (like tac-shotty)
-	var/list/weapon_stats_list = list() // list of types /datum/entity/weapon_stats
-	var/list/job_stats_list = list() // list of types /datum/entity/job_stats
-	var/list/datum/entity/statistic/medal/medal_list = list() // list of all medals earned
+	var/list/weapon_stats_list = list() //! indexed list of types /datum/entity/weapon_stats
+	var/list/job_stats_list = list() //! indexed list of types /datum/entity/job_stats
+	var/datum/entity/weapon_stats/top_weapon //! reference to /datum/entity/weapon_stats (like tac-shotty)
+	var/list/datum/entity/statistic/medal/medal_list = list() //! list of all medals earned
+
+/datum/entity/player_stats/human/Destroy(force)
+	. = ..()
+	QDEL_LIST_ASSOC_VAL(weapon_stats_list)
+	QDEL_LIST_ASSOC_VAL(job_stats_list)
+	QDEL_NULL(top_weapon)
+	QDEL_LIST(medal_list)
 
 /datum/entity/player_stats/human/get_playtime(type)
 	if(!type)

code/datums/statistics/entities/job_stats.dm

@@ -1,8 +1,8 @@
 /datum/entity/player_stats/job
-	var/name = null
-	var/total_friendly_fire = null
-	var/total_revives = null
-	var/total_lives_saved = null
-	var/total_shots = null
-	var/total_shots_hit = null
-	var/total_screams = null
+	var/name
+	var/total_friendly_fire
+	var/total_revives
+	var/total_lives_saved
+	var/total_shots
+	var/total_shots_hit
+	var/total_screams

code/datums/statistics/entities/panel_stats.dm

@@ -8,7 +8,7 @@
 		update_panel_data(round_statistics)
 	ui_interact(user)
 
-/datum/entity/player_entity/proc/ui_interact(mob/user, ui_key = "statistics", datum/nanoui/ui = null, force_open = 1)
+/datum/entity/player_entity/proc/ui_interact(mob/user, ui_key = "statistics", datum/nanoui/ui, force_open = 1)
 	data["menu"] = menu
 	data["subMenu"] = subMenu
 	data["dataMenu"] = dataMenu

code/datums/statistics/entities/player_entity.dm

@@ -8,8 +8,8 @@
 /datum/entity/player_entity
 	var/name
 	var/ckey // "cakey"
-	var/list/datum/entity/player_stats = list()
-	var/list/datum/entity/statistic/death/death_stats = list()
+	var/list/player_stats = list() //! Indeed list of /datum/entity/player_stats
+	var/list/death_stats = list() //! Indexed list of /datum/entity/statistic/death
 	var/menu = 0
 	var/subMenu = 0
 	var/dataMenu = 0
@@ -18,6 +18,11 @@
 	var/savefile_version
 	var/save_loaded = FALSE
 
+/datum/entity/player_entity/Destroy(force)
+	QDEL_LIST_ASSOC_VAL(player_stats)
+	QDEL_LIST_ASSOC_VAL(death_stats)
+	return ..()
+
 /datum/entity/player_entity/proc/get_playtime(branch, type)
 	var/playtime = 0
 	if(player_stats["[branch]"])

code/datums/statistics/entities/player_stats.dm

@@ -6,13 +6,21 @@
 	var/total_rounds_played = 0
 	var/steps_walked = 0
 	var/round_played = FALSE
-	var/datum/entity/statistic/nemesis = null // "runner" = 3
+	var/datum/entity/statistic/nemesis // "runner" = 3
 	var/list/niche_stats = list() // list of type /datum/entity/statistic, "Total Executions" = number
 	var/list/humans_killed = list() // list of type /datum/entity/statistic, "jobname2" = number
 	var/list/xenos_killed = list() // list of type /datum/entity/statistic, "caste" = number
 	var/list/death_list = list() // list of type /datum/entity/death_stats
 	var/display_stat = TRUE
 
+/datum/entity/player_stats/Destroy(force)
+	QDEL_NULL(nemesis)
+	QDEL_LIST_ASSOC_VAL(niche_stats)
+	QDEL_LIST_ASSOC_VAL(humans_killed)
+	QDEL_LIST_ASSOC_VAL(xenos_killed)
+	QDEL_LIST_ASSOC_VAL(death_list)
+	return ..()
+
 /datum/entity/player_stats/proc/get_playtime()
 	return total_playtime
 

code/datums/statistics/entities/round_stats.dm

@@ -23,7 +23,7 @@
 	var/total_slashes = 0
 
 	// untracked data
-	var/datum/entity/statistic/map/current_map = null // reference to current map
+	var/datum/entity/statistic/map/current_map // reference to current map
 	var/list/datum/entity/statistic/death/death_stats_list = list()
 
 	var/list/abilities_used = list() // types of /datum/entity/statistic, "tail sweep" = 10, "screech" = 2
@@ -37,8 +37,20 @@
 	var/list/job_stats_list = list() // list of types /datum/entity/job_stats
 
 	// nanoui data
-	var/round_data[0]
-	var/death_data[0]
+	var/list/round_data = list()
+	var/list/death_data = list()
+
+/datum/entity/statistic/round/Destroy(force)
+	. = ..()
+	QDEL_NULL(current_map)
+	QDEL_LIST(death_stats_list)
+	QDEL_LIST_ASSOC_VAL(abilities_used)
+	QDEL_LIST_ASSOC_VAL(final_participants)
+	QDEL_LIST_ASSOC_VAL(hijack_participants)
+	QDEL_LIST_ASSOC_VAL(total_deaths)
+	QDEL_LIST_ASSOC_VAL(caste_stats_list)
+	QDEL_LIST_ASSOC_VAL(weapon_stats_list)
+	QDEL_LIST_ASSOC_VAL(job_stats_list)
 
 /datum/entity_meta/statistic_round
 	entity_type = /datum/entity/statistic/round

code/datums/statistics/entities/weapon_stats.dm

@@ -1,16 +1,23 @@
 /datum/entity/weapon_stats
-	var/datum/entity/player = null // "deanthelis"
-	var/list/niche_stats = list() // list of type /datum/entity/statistic, "Total Reloads" = number
-	var/list/humans_killed = list() // list of type /datum/entity/statistic, "jobname2" = number
-	var/list/xenos_killed = list() // list of type /datum/entity/statistic, "caste" = number
-	var/name = null
+	var/datum/entity/player
+	var/list/niche_stats = list() //! Indexed list of /datum/entity/statistic, "Total Reloads" = number
+	var/list/humans_killed = list() //! Indexed list of /datum/entity/statistic, "jobname2" = number
+	var/list/xenos_killed = list() //! Indexed list of /datum/entity/statistic, "caste" = number
+	var/name
 	var/total_kills = 0
-	var/total_hits = null
-	var/total_shots = null
-	var/total_shots_hit = null
-	var/total_friendly_fire = null
+	var/total_hits
+	var/total_shots
+	var/total_shots_hit
+	var/total_friendly_fire
 	var/display_stat = TRUE
 
+/datum/entity/weapon_stats/Destroy(force)
+	player = null
+	QDEL_LIST_ASSOC_VAL(niche_stats)
+	QDEL_LIST_ASSOC_VAL(humans_killed)
+	QDEL_LIST_ASSOC_VAL(xenos_killed)
+	return ..()
+
 /datum/entity/weapon_stats/proc/count_human_kill(job_name)
 	if(!job_name)
 		return

code/datums/statistics/entities/xeno_stats.dm

@@ -4,6 +4,12 @@
 	var/list/caste_stats_list = list() // list of types /datum/entity/player_stats/caste
 	var/list/datum/entity/statistic/medal/medal_list = list() // list of all royal jelly earned
 
+/datum/entity/player_stats/xeno/Destroy(force)
+	. = ..()
+	QDEL_NULL(top_caste)
+	QDEL_LIST_ASSOC_VAL(caste_stats_list)
+	QDEL_LIST(medal_list)
+
 /datum/entity/player_stats/xeno/get_playtime(type)
 	if(!type || type == FACTION_XENOMORPH)
 		return ..()