Fixes the Hive Status error when the Queen dies

code/modules/mob/living/carbon/xenomorph/Xenomorph.dm

@@ -432,6 +432,9 @@
 	if(mob_size < MOB_SIZE_BIG)
 		mob_flags |= SQUEEZE_UNDER_VEHICLES
 
+	GLOB.living_xeno_list += src
+	GLOB.xeno_mob_list += src
+
 	// More setup stuff for names, abilities etc
 	update_icon_source()
 	generate_name()
@@ -453,9 +456,6 @@
 	//Begin SStracking
 	SStracking.start_tracking("hive_[src.hivenumber]", src)
 
-	GLOB.living_xeno_list += src
-	GLOB.xeno_mob_list += src
-
 	//WO GAMEMODE
 	if(SSticker?.mode?.hardcore)
 		hardcore = 1 //Prevents healing and queen evolution

code/modules/mob/living/carbon/xenomorph/hive_status.dm

@@ -422,28 +422,27 @@
 // The idea is that we sort this list, and use it as a "key" for all the other information (especially the nicknumber)
 // in the hive status UI. That way we can minimize the amount of sorts performed by only calling this when xenos are created/disposed
 /datum/hive_status/proc/get_xeno_keys()
-	var/list/xenos[totalXenos.len]
+	var/list/xenos = list()
 
-	var/index = 1
-	var/useless_slots = 0
 	for(var/mob/living/carbon/xenomorph/X in totalXenos)
 		if(should_block_game_interaction(X))
 			var/area/A = get_area(X)
 			if(!(A.flags_atom & AREA_ALLOW_XENO_JOIN))
-				useless_slots++
 				continue
 
-		// Insert without doing list merging
-		xenos[index++] = list(
+		if(!(X in GLOB.living_xeno_list))
+			continue
+
+		// This looks weird, but in DM adding List A to List B actually adds each item in List B to List A, not List B itself.
+		// Having a nested list like this sort of tricks it into adding the list instead.
+		// In this case this results in an array of different 'xeno' dictionaries, rather than just a dictionary.
+		xenos += list(list(
 			"nicknumber" = X.nicknumber,
 			"tier" = X.tier, // This one is only important for sorting
 			"is_leader" = (IS_XENO_LEADER(X)),
 			"is_queen" = istype(X.caste, /datum/caste_datum/queen),
 			"caste_type" = X.caste_type
-		)
-
-	// Clear nulls from the xenos list
-	xenos.len -= useless_slots
+		))
 
 	// Make it all nice and fancy by sorting the list before returning it
 	var/list/sorted_keys = sort_xeno_keys(xenos)

code/modules/mob/living/carbon/xenomorph/hive_status_ui.dm

@@ -123,6 +123,10 @@
 	if(isobserver(user))
 		return UI_INTERACTIVE
 
+	// If the Queen died or is otherwise missing.
+	if(!assoc_hive.living_xeno_queen)
+		return UI_CLOSE
+
 /datum/hive_status_ui/ui_data(mob/user)
 	. = list()
 	.["total_xenos"] = total_xenos
@@ -131,7 +135,9 @@
 	.["xeno_keys"] = xeno_keys
 	.["xeno_info"] = xeno_info
 	.["xeno_vitals"] = xeno_vitals
-	.["queen_location"] = get_area_name(assoc_hive.living_xeno_queen)
+	.["queen_location"] = null
+	if(assoc_hive.living_xeno_queen)
+		.["queen_location"] = get_area_name(assoc_hive.living_xeno_queen)
 	.["hive_location"] = hive_location
 	.["burrowed_larva"] = burrowed_larva
 	.["evilution_level"] = evilution_level

tgui/packages/tgui/interfaces/HiveStatus.jsx

@@ -117,10 +117,16 @@ const GeneralInformation = (props, context) => {
 
   return (
     <Flex direction="column" align="center">
-      <Flex.Item textAlign="center">
-        <h3 className="whiteTitle">The Queen is in:</h3>
-        <h1 className="whiteTitle">{queen_location}</h1>
-      </Flex.Item>
+      {queen_location === null ? (
+        <Flex.Item textAlign="center">
+          <h3 className="whiteTitle">The Hive has no Queen!</h3>
+        </Flex.Item>
+      ) : (
+        <Flex.Item textAlign="center">
+          <h3 className="whiteTitle">The Queen is in:</h3>
+          <h1 className="whiteTitle">{queen_location}</h1>
+        </Flex.Item>
+      )}
       {!!hive_location && (
         <Flex.Item textAlign="center" mt={2}>
           <h3 className="whiteTitle">The Hive location is:</h3>