Fixes modified MA overlays potentially causing duplicate overlays

code/game/atoms.dm

@@ -768,7 +768,6 @@
 
 /// Updates the icon of the atom
 /atom/proc/update_icon(updates=ALL)
-	SIGNAL_HANDLER
 	SHOULD_CALL_PARENT(TRUE)
 
 	. = NONE
@@ -782,19 +781,54 @@
 			SSvis_overlays.remove_vis_overlay(src, managed_vis_overlays)
 
 		var/list/new_overlays = update_overlays(updates)
-		if (managed_overlays)
-			if (length(overlays) == (islist(managed_overlays) ? length(managed_overlays) : 1))
-				overlays = null
-				POST_OVERLAY_CHANGE(src)
-			else
-				cut_overlay(managed_overlays)
-				managed_overlays = null
-		if(length(new_overlays))
-			if (length(new_overlays) == 1)
-				managed_overlays = new_overlays[1]
-			else
-				managed_overlays = new_overlays
-			add_overlay(new_overlays)
+		var/nulls = 0
+		for(var/i in 1 to length(new_overlays))
+			var/atom/maybe_not_an_atom = new_overlays[i]
+			if(isnull(maybe_not_an_atom))
+				nulls++
+				continue
+			if(istext(maybe_not_an_atom) || isicon(maybe_not_an_atom))
+				continue
+			new_overlays[i] = maybe_not_an_atom.appearance
+		if(nulls)
+			for(var/i in 1 to nulls)
+				new_overlays -= null
+
+		var/identical = FALSE
+		var/new_length = length(new_overlays)
+		if(!managed_overlays && !new_length)
+			identical = TRUE
+		else if(!islist(managed_overlays))
+			if(new_length == 1 && managed_overlays == new_overlays[1])
+				identical = TRUE
+		else if(length(managed_overlays) == new_length)
+			identical = TRUE
+			for(var/i in 1 to length(managed_overlays))
+				if(managed_overlays[i] != new_overlays[i])
+					identical = FALSE
+					break
+
+		if(!identical)
+			var/full_control = FALSE
+			if(managed_overlays)
+				full_control = length(overlays) == (islist(managed_overlays) ? length(managed_overlays) : 1)
+				if(full_control)
+					overlays = null
+				else
+					cut_overlay(managed_overlays)
+
+			switch(length(new_overlays))
+				if(0)
+					if(full_control)
+						POST_OVERLAY_CHANGE(src)
+					managed_overlays = null
+				if(1)
+					add_overlay(new_overlays)
+					managed_overlays = new_overlays[1]
+				else
+					add_overlay(new_overlays)
+					managed_overlays = new_overlays
+
 		. |= UPDATE_OVERLAYS
 
 	. |= SEND_SIGNAL(src, COMSIG_ATOM_UPDATED_ICON, updates, .)

code/game/objects/items/devices/radio/radio.dm

@@ -484,9 +484,9 @@
 	. = ..()
 	if(unscrewed)
 		return
-	if(broadcasting)
+	if(broadcasting && overlay_mic_idle)
 		. += overlay_mic_idle
-	if(listening)
+	if(listening && overlay_speaker_idle)
 		. += overlay_speaker_idle
 
 /obj/item/radio/screwdriver_act(mob/living/user, obj/item/tool)

code/modules/reagents/reagent_containers/cups/drinks.dm

@@ -227,8 +227,8 @@
 	custom_price = PAYCHECK_LOWER * 0.8
 
 /obj/item/reagent_containers/cup/glass/waterbottle/Initialize(mapload)
-	. = ..()
 	cap_overlay = mutable_appearance(cap_icon, cap_icon_state)
+	. = ..()
 	if(cap_on)
 		spillable = FALSE
 		update_appearance()

code/modules/reagents/reagent_containers/syringes.dm

@@ -145,7 +145,9 @@
 
 /obj/item/reagent_containers/syringe/update_overlays()
 	. = ..()
-	. += update_reagent_overlay()
+	var/list/reagent_overlays = update_reagent_overlay()
+	if(reagent_overlays)
+		. += reagent_overlays
 
 /// Returns a list of overlays to add that relate to the reagents inside the syringe
 /obj/item/reagent_containers/syringe/proc/update_reagent_overlay()