[MIRROR] Resolves mutant species keeping old organs they shouldn't have [MDB IGNORE] (#19958)

* Resolves mutant species keeping old organs they shouldn't have (#73728)

## About The Pull Request

regenerate organs never removed invalid organs when regenerating
## Why It's Good For The Game

Fixes https://github.com/tgstation/tgstation/issues/73640
adds a unit test to prevent regressions in the future

## Changelog
🆑
fix: Plasmamen don't have hearts, again
/🆑

* Resolves mutant species keeping old organs they shouldn't have

* https://github.com/tgstation/tgstation/pull/68168

* Now everything should pass, yes, even appendixes for synths

---------

Co-authored-by: Zephyr <12817816+ZephyrTFA@users.noreply.github.com>
Co-authored-by: GoldenAlpharex <jerego1234@hotmail.com>
Co-authored-by: Coffee <CoffeeDragon16@gmail.com>

code/modules/mob/living/carbon/human/species.dm

@@ -172,9 +172,9 @@ GLOBAL_LIST_EMPTY(features_by_species)
 	///What anim to use for gibbing
 	var/gib_anim = "gibbed-h"
 
-
-	//Do NOT remove by setting to null. use OR make an ASSOCIATED TRAIT.
-	//why does it work this way? because traits also disable the downsides of not having an organ, removing organs but not having the trait will make your species die
+	// Prefer anything other than setting these to null, such as TRAITS
+	// why?
+	// because traits also disable the downsides of not having an organ, removing organs but not having the trait or logic will make your species die
 
 	///Replaces default brain with a different organ
 	var/obj/item/organ/internal/brain/mutantbrain = /obj/item/organ/internal/brain
@@ -350,6 +350,9 @@ GLOBAL_LIST_EMPTY(features_by_species)
 		var/obj/item/organ/oldorgan = C.getorganslot(slot) //used in removing
 		var/obj/item/organ/neworgan = slot_mutantorgans[slot] //used in adding
 		if(!neworgan) //these can be null, if so we shouldn't regenerate
+			if(oldorgan) // although we also need to remove the old organ if it exists
+				oldorgan.Remove(C, special=TRUE)
+				qdel(oldorgan)
 			continue
 
 		if(visual_only && !initial(neworgan.visual))
@@ -367,7 +370,7 @@ GLOBAL_LIST_EMPTY(features_by_species)
 		 * - The replaced organ is not in an excluded zone
 		 * - The replaced organ is not unremovable or synthetic (an implant)
 		 */
-		if(oldorgan && (!should_have || replace_current) && !(oldorgan.zone in excluded_zones) && !(oldorgan.organ_flags & (ORGAN_UNREMOVABLE|ORGAN_SYNTHETIC)))
+		if(oldorgan && (!should_have || replace_current) && !(oldorgan.zone in excluded_zones) && (!(oldorgan.organ_flags & (ORGAN_UNREMOVABLE|ORGAN_SYNTHETIC)) || (oldorgan.organ_flags & ORGAN_SYNTHETIC_FROM_SPECIES))) // SKYRAT EDIT - Customization - ORIGINAL: if(oldorgan && (!should_have || replace_current) && !(oldorgan.zone in excluded_zones) && !(oldorgan.organ_flags & (ORGAN_UNREMOVABLE|ORGAN_SYNTHETIC)))
 			if(slot == ORGAN_SLOT_BRAIN)
 				var/obj/item/organ/internal/brain/brain = oldorgan
 				if(!brain.decoy_override)//"Just keep it if it's fake" - confucius, probably

code/modules/mob/living/carbon/human/species_types/golems.dm

@@ -25,7 +25,6 @@
 	mutantlungs = null
 	inherent_biotypes = MOB_HUMANOID|MOB_MINERAL
 	mutant_organs = list(/obj/item/organ/internal/adamantine_resonator)
-	mutanttongue = /obj/item/organ/internal/vocal_cords/adamantine
 	speedmod = 2
 	payday_modifier = 0.75
 	armor = 55
@@ -88,8 +87,7 @@
 	name = "Adamantine Golem"
 	id = SPECIES_GOLEM_ADAMANTINE
 	meat = /obj/item/food/meat/slab/human/mutant/golem/adamantine
-	mutant_organs = list(/obj/item/organ/internal/adamantine_resonator)
-	mutanttongue = /obj/item/organ/internal/vocal_cords/adamantine
+	mutant_organs = list(/obj/item/organ/internal/adamantine_resonator, /obj/item/organ/internal/vocal_cords/adamantine)
 	fixed_mut_color = "#44eedd"
 	info_text = "As an <span class='danger'>Adamantine Golem</span>, you possess special vocal cords allowing you to \"resonate\" messages to all golems. Your unique mineral makeup makes you immune to most types of magic."
 	prefix = "Adamantine"

code/modules/surgery/organs/external/_external_organs.dm

@@ -168,7 +168,7 @@
 	//Build the mob sprite and use it as our overlay
 	for(var/external_layer in bodypart_overlay.all_layers)
 		if(bodypart_overlay.layers & external_layer)
-			. += bodypart_overlay.get_overlay(external_layer, limb = null)
+			. += bodypart_overlay.get_overlay(external_layer, ownerlimb)
 
 ///The horns of a lizard!
 /obj/item/organ/external/horns
@@ -366,8 +366,11 @@
 	if(draw_layer != bitflag_to_layer(color_swapped_layer))
 		return ..()
 
-	var/list/rgb_list = rgb2num(draw_color)
-	overlay.color = rgb(color_inverse_base - rgb_list[1], color_inverse_base - rgb_list[2], color_inverse_base - rgb_list[3]) //inversa da color
+	if(draw_color) // can someone explain to me why draw_color is allowed to EVER BE AN EMPTY STRING
+		var/list/rgb_list = rgb2num(draw_color)
+		overlay.color = rgb(color_inverse_base - rgb_list[1], color_inverse_base - rgb_list[2], color_inverse_base - rgb_list[3]) //inversa da color
+	else
+		overlay.color = null
 
 /datum/bodypart_overlay/mutant/pod_hair/can_draw_on_bodypart(mob/living/carbon/human/human)
 	if((human.head?.flags_inv & HIDEHAIR) || (human.wear_mask?.flags_inv & HIDEHAIR))

code/modules/unit_tests/_unit_tests.dm

@@ -156,6 +156,7 @@
 #include "monkey_business.dm"
 #include "mouse_bite_cable.dm"
 #include "mutant_hands_consistency.dm"
+#include "mutant_organs.dm"
 #include "novaflower_burn.dm"
 #include "ntnetwork_tests.dm"
 #include "nuke_cinematic.dm"

code/modules/unit_tests/mutant_organs.dm

@@ -0,0 +1,65 @@
+/**
+ * Iterates over all species to ensure that organs are valid after being set to a mutant species
+ */
+/datum/unit_test/mutant_organs
+
+/datum/unit_test/mutant_organs/Run()
+	var/mob/living/carbon/human/consistent/dummy = allocate(/mob/living/carbon/human/consistent)
+	var/list/ignore = list(
+		/datum/species/dullahan,
+	)
+	var/list/species = subtypesof(/datum/species) - ignore
+	var/static/list/organs_we_care_about = list(
+		ORGAN_SLOT_BRAIN,
+		ORGAN_SLOT_HEART,
+		ORGAN_SLOT_LUNGS,
+		ORGAN_SLOT_EYES,
+		ORGAN_SLOT_EARS,
+		ORGAN_SLOT_TONGUE,
+		ORGAN_SLOT_LIVER,
+		ORGAN_SLOT_STOMACH,
+		ORGAN_SLOT_APPENDIX,
+	)
+
+	for(var/datum/species/species_type as anything in species)
+		// change them to the species
+		dummy.set_species(species_type)
+
+		// check all their organs
+		for(var/organ_slot in organs_we_care_about)
+			var/expected_type = slot_to_species_organ_type(organ_slot, species_type)
+			var/obj/item/organ/actual_organ = dummy.getorganslot(organ_slot)
+			if(isnull(actual_organ))
+				if(!isnull(expected_type))
+					TEST_FAIL("[species_type] did not update their [organ_slot] organ to [expected_type], no organ was found")
+					continue
+			else
+				if(isnull(expected_type))
+					TEST_FAIL("[species_type] did not remove their [organ_slot] organ")
+					continue
+
+				if(actual_organ.type != expected_type)
+					TEST_FAIL("[species_type] did not update their [organ_slot] organ to [expected_type], instead it was [actual_organ.type]")
+					continue
+
+/datum/unit_test/mutant_organs/proc/slot_to_species_organ_type(slot, datum/species/species)
+	switch(slot)
+		if(ORGAN_SLOT_BRAIN)
+			return initial(species.mutantbrain)
+		if(ORGAN_SLOT_HEART)
+			return initial(species.mutantheart)
+		if(ORGAN_SLOT_LUNGS)
+			return initial(species.mutantlungs)
+		if(ORGAN_SLOT_EYES)
+			return initial(species.mutanteyes)
+		if(ORGAN_SLOT_EARS)
+			return initial(species.mutantears)
+		if(ORGAN_SLOT_TONGUE)
+			return initial(species.mutanttongue)
+		if(ORGAN_SLOT_LIVER)
+			return initial(species.mutantliver)
+		if(ORGAN_SLOT_STOMACH)
+			return initial(species.mutantstomach)
+		if(ORGAN_SLOT_APPENDIX)
+			return initial(species.mutantappendix)
+	CRASH("Invalid organ slot [slot]") // just incase someone adds an organ we care about and forgets to add it here