save when a faction is disband, change the value of area.faction_open with the old playerfactions version to facilitate the switch into the new one

chatcommands.lua

@@ -304,7 +304,7 @@ if areas.factions_available then
 						.." or is not owned by you.", id)
 			end
 			if factions.version == nil or factions.version < 2 or factions.mode_unique_faction then
-				local open = not areas.areas[id].faction_open and factions.get_player_faction(name)
+				local open = not areas.areas[id].faction_open and {factions.get_player_faction(name)}
 				-- Save false as nil to avoid inflating the DB.
 				areas.areas[id].faction_open = open or nil
 				areas:save()
@@ -322,8 +322,8 @@ if areas.factions_available then
 				local removed = false
 				for i, fac_name in ipairs(fnames) do
 					if faction_name == fac_name then
-						removed = true
 						table.remove(fnames,i)
+						removed = true
 					end
 				end
 				if not removed then
@@ -332,7 +332,7 @@ if areas.factions_available then
 				if #fnames == 0 then
 					fnames = nil
 				end
-				-- Save false as nil to avoid inflating the DB.
+				-- Save {} as nil to avoid inflating the DB.
 				areas.areas[id].faction_open = fnames
 				areas:save()
 				return true, fnames and S("Area is open for members of: @1",table.concat(fnames,", "))

hud.lua

@@ -25,17 +25,23 @@ minetest.register_globalstep(function(dtime)
 				if factions.version == nil or factions.version < 2 then
 					faction_info = factions.get_player_faction(area.owner)
 				else
+					-- Verify that every displayed faction still exists
+					local faction_open_changed = false
 					for i, fac_name in ipairs(area.faction_open) do
 						if not factions.get_owner(fac_name) then
 							table.remove(area.faction_open, i)
+							faction_open_changed = true
 						end
 					end
 					if #area.faction_open == 0 then
 						area.faction_open = nil
 						faction_info = nil
+						faction_open_changed = true
 					else
 						faction_info = table.concat(area.faction_open, ", ")
 					end
+					-- Save areas if a faction was disband
+					if faction_open_changed then areas:save()	end
 				end
 			end