Add workaround for spigot disable issue

main/src/main/java/net/citizensnpcs/Citizens.java

@@ -76,8 +76,8 @@ public class Citizens extends JavaPlugin implements CitizensPlugin {
     private final List<NPCRegistry> anonymousRegistries = Lists.newArrayList();
     private final List<NPCRegistry> citizensBackedRegistries = Lists.newArrayList();
     private final CommandManager commands = new CommandManager();
-    private boolean compatible;
     private Settings config;
+    private boolean loaded;
     private CitizensNPCRegistry npcRegistry;
     private NPCDataStore saves;
     private NPCSelector selector;
@@ -145,6 +145,19 @@ public class Citizens extends JavaPlugin implements CitizensPlugin {
         }
     }
 
+    public void disable() {
+        if (loaded) {
+            Bukkit.getPluginManager().callEvent(new CitizensDisableEvent());
+            Editor.leaveAll();
+            despawnNPCs(true);
+            npcRegistry = null;
+            NMS.shutdown();
+            loaded = false;
+        }
+
+        CitizensAPI.shutdown();
+    }
+
     private void enableSubPlugins() {
         File root = new File(getDataFolder(), Setting.SUBPLUGIN_FOLDER.asString());
         if (!root.exists() || !root.isDirectory())
@@ -277,16 +290,7 @@ public class Citizens extends JavaPlugin implements CitizensPlugin {
 
     @Override
     public void onDisable() {
-        Bukkit.getPluginManager().callEvent(new CitizensDisableEvent());
-        Editor.leaveAll();
-
-        if (compatible) {
-            despawnNPCs(true);
-            npcRegistry = null;
-            NMS.shutdown();
-        }
-
-        CitizensAPI.shutdown();
+        disable();
     }
 
     @Override
@@ -296,11 +300,11 @@ public class Citizens extends JavaPlugin implements CitizensPlugin {
         setupTranslator();
         // Disable if the server is not using the compatible Minecraft version
         String mcVersion = Util.getMinecraftRevision();
-        compatible = true;
+        loaded = true;
         try {
             NMS.loadBridge(mcVersion);
         } catch (Exception e) {
-            compatible = false;
+            loaded = false;
             if (Messaging.isDebugging()) {
                 e.printStackTrace();
             }

main/src/main/java/net/citizensnpcs/EventListen.java

@@ -1,5 +1,6 @@
 package net.citizensnpcs;
 
+import java.lang.invoke.MethodHandle;
 import java.util.Collection;
 import java.util.List;
 import java.util.Map;
@@ -42,6 +43,7 @@ import org.bukkit.event.player.PlayerQuitEvent;
 import org.bukkit.event.player.PlayerRespawnEvent;
 import org.bukkit.event.player.PlayerTeleportEvent;
 import org.bukkit.event.player.PlayerTeleportEvent.TeleportCause;
+import org.bukkit.event.server.PluginDisableEvent;
 import org.bukkit.event.vehicle.VehicleDamageEvent;
 import org.bukkit.event.vehicle.VehicleDestroyEvent;
 import org.bukkit.event.vehicle.VehicleEnterEvent;
@@ -51,6 +53,7 @@ import org.bukkit.event.world.WorldLoadEvent;
 import org.bukkit.event.world.WorldUnloadEvent;
 import org.bukkit.inventory.meta.SkullMeta;
 import org.bukkit.metadata.FixedMetadataValue;
+import org.bukkit.plugin.java.JavaPlugin;
 import org.bukkit.scheduler.BukkitRunnable;
 
 import com.google.common.base.Predicates;
@@ -228,6 +231,28 @@ public class EventListen implements Listener {
         checkCreationEvent(event);
     }
 
+    @EventHandler
+    public void onDisable(PluginDisableEvent event) {
+        // hack: Spigot now unloads plugin classes on disable in reverse order so prefer unloading at the start of
+        // plugin disable cycle
+        if (event.getPlugin() instanceof JavaPlugin) {
+            try {
+                MethodHandle field = CLASSES_FIELD == null
+                        ? CLASSES_FIELD = NMS.getGetter(event.getPlugin().getPluginLoader().getClass(), "classes")
+                        : CLASSES_FIELD;
+                Map<String, Class<?>> classes = (Map<String, Class<?>>) field
+                        .invoke(event.getPlugin().getPluginLoader());
+                if (classes.containsKey("net.citizensnpcs.api.CitizensAPI")) {
+                    CitizensAPI.getPlugin().onDisable();
+                }
+            } catch (Throwable e) {
+                CitizensAPI.getPlugin().onDisable();
+            }
+        } else {
+            CitizensAPI.getPlugin().onDisable();
+        }
+    }
+
     /*
      * Entity events
      */
@@ -717,4 +742,6 @@ public class EventListen implements Listener {
         }
         return npc.spawn(spawn, SpawnReason.CHUNK_LOAD);
     }
+
+    private static MethodHandle CLASSES_FIELD = null;
 }

main/src/main/java/net/citizensnpcs/commands/NPCCommands.java

@@ -114,6 +114,8 @@ import net.citizensnpcs.trait.RabbitType;
 import net.citizensnpcs.trait.ScoreboardTrait;
 import net.citizensnpcs.trait.ScriptTrait;
 import net.citizensnpcs.trait.SheepTrait;
+import net.citizensnpcs.trait.ShopTrait;
+import net.citizensnpcs.trait.ShopTrait.NPCShop;
 import net.citizensnpcs.trait.SkinLayers;
 import net.citizensnpcs.trait.SkinLayers.Layer;
 import net.citizensnpcs.trait.SkinTrait;
@@ -1919,6 +1921,29 @@ public class NPCCommands {
         }
     }
 
+    @Command(
+            aliases = { "npc" },
+            usage = "shop (name) (editr)",
+            desc = "NPC shop edit/show",
+            modifiers = { "shop" },
+            min = 1,
+            max = 3,
+            permission = "citizens.npc.shop")
+    public void shop(CommandContext args, Player sender, NPC npc) throws CommandException {
+        ShopTrait trait = npc.getOrAddTrait(ShopTrait.class);
+        if (args.argsLength() > 1) {
+            NPCShop shop = trait.getShop(args.getString(1));
+            if (args.getString(1).equalsIgnoreCase("edit")) {
+            } else if (args.getString(1).equalsIgnoreCase("show") && args.argsLength() == 3) {
+                shop.display(sender);
+            } else {
+                throw new CommandUsageException();
+            }
+        } else {
+            trait.getDefaultShop().display(sender);
+        }
+    }
+
     @Command(
             aliases = { "npc" },
             usage = "skin (-c -l(atest)) [name] (or --url [url] or -t [uuid/name] [data] [signature])",

main/src/main/java/net/citizensnpcs/npc/CitizensTraitFactory.java

@@ -46,6 +46,7 @@ import net.citizensnpcs.trait.Saddle;
 import net.citizensnpcs.trait.ScoreboardTrait;
 import net.citizensnpcs.trait.ScriptTrait;
 import net.citizensnpcs.trait.SheepTrait;
+import net.citizensnpcs.trait.ShopTrait;
 import net.citizensnpcs.trait.SkinLayers;
 import net.citizensnpcs.trait.SkinTrait;
 import net.citizensnpcs.trait.SlimeSize;
@@ -92,6 +93,7 @@ public class CitizensTraitFactory implements TraitFactory {
         registerTrait(TraitInfo.create(SkinTrait.class));
         registerTrait(TraitInfo.create(MountTrait.class));
         registerTrait(TraitInfo.create(SlimeSize.class));
+        registerTrait(TraitInfo.create(ShopTrait.class));
         registerTrait(TraitInfo.create(Spawned.class));
         registerTrait(TraitInfo.create(Speech.class));
         registerTrait(TraitInfo.create(Text.class));

main/src/main/java/net/citizensnpcs/trait/ShopTrait.java

@@ -0,0 +1,46 @@
+package net.citizensnpcs.trait;
+
+import java.util.Map;
+
+import org.bukkit.entity.Player;
+
+import com.google.common.collect.Maps;
+
+import net.citizensnpcs.api.persistence.Persist;
+import net.citizensnpcs.api.trait.Trait;
+import net.citizensnpcs.api.trait.TraitName;
+
+/**
+ * Shop trait for NPC GUI shops.
+ */
+@TraitName("shop")
+public class ShopTrait extends Trait {
+    public ShopTrait() {
+        super("shop");
+    }
+
+    public NPCShop getDefaultShop() {
+        return NPC_SHOPS.get(npc.getUniqueId().toString());
+    }
+
+    public NPCShop getShop(String name) {
+        return SHOPS.get(name);
+    }
+
+    public static class NPCShop {
+        @Persist
+        String name;
+
+        private NPCShop(String name) {
+            this.name = name;
+        }
+
+        public void display(Player sender) {
+        }
+    }
+
+    @Persist(value = "npcShops", namespace = "shopstrait")
+    private static Map<String, NPCShop> NPC_SHOPS = Maps.newHashMap();
+    @Persist(value = "namedShops", namespace = "shopstrait")
+    private static Map<String, NPCShop> SHOPS = Maps.newHashMap();
+}