read-only alist support for VV (#95501)

## About The Pull Request

This adds experimental read-only support for `/alist`s in VV.

I'm not quite sure how to add support for properly changing alists, but
this is better than nothing at least.

### Before

<img width="474" height="262" alt="image"
src="https://github.com/user-attachments/assets/8701fc64-855b-429e-88d1-f6607000b2c8"
/>

### After

<img width="943" height="539" alt="2026-03-23 (1774313721) ~
dreamseeker"
src="https://github.com/user-attachments/assets/cb6caf2a-19fd-49a9-b228-1bccb2c315f3"
/>

## Why It's Good For The Game

Should be able to at least view alists with VV.

## Changelog
🆑
admin: View Variables can now properly view alists, altho it cannot edit
them.
/🆑

code/modules/admin/view_variables/debug_variables.dm

@@ -2,7 +2,9 @@
 /// Get displayed variable in VV variable list
 /proc/debug_variable(name, value, level, datum/owner, sanitize = TRUE, display_flags = NONE) //if D is a list, name will be index, and value will be assoc value.
 	if(owner)
-		if(islist(owner))
+		if(isalist(owner))
+			. = "<li style='backgroundColor:white'>(READ ONLY) "
+		else if(islist(owner))
 			var/list/list_owner = owner
 			var/index = name
 			if (isnull(value))
@@ -64,6 +66,18 @@
 		var/datum/datum_value = value
 		return datum_value.debug_variable_value(name, level, owner, sanitize, display_flags)
 
+	if(isalist(value))
+		var/alist/alist_value = value
+		var/list/items = list()
+
+		var/link_vars = "Vars=[REF(value)]"
+
+		if (!(display_flags & VV_ALWAYS_CONTRACT_LIST) && alist_value.len > 0 && alist_value.len <= VV_NORMAL_LIST_NO_EXPAND_THRESHOLD)
+			for(var/key, val in alist_value)
+				items += debug_variable(key, val, level + 1, sanitize = sanitize)
+			return "<a href='byond://?_src_=vars;[HrefToken()];[link_vars]'>/alist ([alist_value.len])</a><ul>[items.Join()]</ul>"
+		return "<a href='byond://?_src_=vars;[HrefToken()];[link_vars]'>/alist ([alist_value.len])</a>"
+
 	if(islist(value) || (name in GLOB.vv_special_lists)) // Some special lists aren't detectable as a list through istype
 		var/list/list_value = value
 		var/list/items = list()

code/modules/admin/view_variables/modify_variables.dm

@@ -113,6 +113,9 @@ GLOBAL_PROTECT(VVpixelmovement)
 	if(!istype(L, /list))
 		to_chat(src, "Not a List.", confidential = TRUE)
 		return
+	if(isalist(L))
+		to_chat(src, "alists are currently unsupported", confidential = TRUE)
+		return
 
 	if(L.len > 1000)
 		var/confirm = tgui_alert(usr, "The list you're trying to edit is very long, continuing may crash the server.", "Warning", list("Continue", "Abort"))

code/modules/admin/view_variables/reference_tracking.dm

@@ -197,7 +197,7 @@ GLOBAL_ALIST_EMPTY(reftracker_skip_typecache_b)
 
 	else if(islist(potential_container))
 		var/list/potential_cache = potential_container
-		var/is_alist = istype(potential_cache, /alist)
+		var/is_alist = isalist(potential_cache)
 		for(var/element_in_list in potential_cache)
 			//Check normal sublists
 			if(islist(element_in_list))

code/modules/admin/view_variables/view_variables.dm

@@ -23,13 +23,14 @@ ADMIN_VERB_ONLY_CONTEXT_MENU(debug_variables, R_NONE, "View Variables", datum/th
 	var/islist = islist(thing) || (!isdatum(thing) && hascall(thing, "Cut")) // Some special lists don't count as lists, but can be detected by if they have list procs
 	if(!islist && !isdatum(thing))
 		return
+	var/isalist = isalist(thing) // islist will always be true for alists too
 
 	var/title = ""
 	var/refid = REF(thing)
 	var/icon/sprite
 	var/hash
 
-	var/type = islist ? /list : thing.type
+	var/type = islist ? (isalist ? /alist : /list) : thing.type
 	var/no_icon = FALSE
 
 	if(isatom(thing))
@@ -67,7 +68,7 @@ ADMIN_VERB_ONLY_CONTEXT_MENU(debug_variables, R_NONE, "View Variables", datum/th
 	title = "[thing] ([REF(thing)]) = [type]"
 	var/formatted_type = replacetext("[type]", "/", "<wbr>/")
 
-	var/list/header = islist ? list("<b>/list</b>") : thing.vv_get_header()
+	var/list/header = islist ? (isalist ? list("<b>/alist</b>") : list("<b>/list</b>")) : thing.vv_get_header()
 
 	var/ref_line = "@[copytext(refid, 2, -1)]" // get rid of the brackets, add a @ prefix for copy pasting in asay
 
@@ -87,14 +88,20 @@ ADMIN_VERB_ONLY_CONTEXT_MENU(debug_variables, R_NONE, "View Variables", datum/th
 
 	var/list/dropdownoptions
 	if (islist)
-		dropdownoptions = list(
-			"Add Item" = VV_HREF_TARGETREF_INTERNAL(refid, VV_HK_LIST_ADD),
-			"Remove Nulls" = VV_HREF_TARGETREF_INTERNAL(refid, VV_HK_LIST_ERASE_NULLS),
-			"Remove Dupes" = VV_HREF_TARGETREF_INTERNAL(refid, VV_HK_LIST_ERASE_DUPES),
-			"Set len" = VV_HREF_TARGETREF_INTERNAL(refid, VV_HK_LIST_SET_LENGTH),
-			"Shuffle" = VV_HREF_TARGETREF_INTERNAL(refid, VV_HK_LIST_SHUFFLE),
-			"Show VV To Player" = VV_HREF_TARGETREF_INTERNAL(refid, VV_HK_EXPOSE),
-			"---"
+		if(!isalist)
+			dropdownoptions = list(
+				"Add Item" = VV_HREF_TARGETREF_INTERNAL(refid, VV_HK_LIST_ADD),
+				"Remove Nulls" = VV_HREF_TARGETREF_INTERNAL(refid, VV_HK_LIST_ERASE_NULLS),
+				"Remove Dupes" = VV_HREF_TARGETREF_INTERNAL(refid, VV_HK_LIST_ERASE_DUPES),
+				"Set len" = VV_HREF_TARGETREF_INTERNAL(refid, VV_HK_LIST_SET_LENGTH),
+				"Shuffle" = VV_HREF_TARGETREF_INTERNAL(refid, VV_HK_LIST_SHUFFLE),
+				"Show VV To Player" = VV_HREF_TARGETREF_INTERNAL(refid, VV_HK_EXPOSE),
+				"---"
+			)
+		else
+			dropdownoptions = list(
+				"Show VV To Player" = VV_HREF_TARGETREF_INTERNAL(refid, VV_HK_EXPOSE),
+				"---"
 			)
 		for(var/i in 1 to length(dropdownoptions))
 			var/name = dropdownoptions[i]
@@ -113,7 +120,11 @@ ADMIN_VERB_ONLY_CONTEXT_MENU(debug_variables, R_NONE, "View Variables", datum/th
 	var/ui_scale = prefs?.read_preference(/datum/preference/toggle/ui_scale)
 
 	var/list/variable_html = list()
-	if(islist)
+	if(isalist)
+		var/alist/alist_value = thing
+		for(var/key, value in alist_value)
+			variable_html += debug_variable(key, value, 0, alist_value)
+	else if(islist)
 		var/list/list_value = thing
 		for(var/i in 1 to list_value.len)
 			var/key = list_value[i]