From 3f36a52685ec3456a31214cc759ae48c4d35f9fe Mon Sep 17 00:00:00 2001
From: triagonal <10545540+triagonal@users.noreply.github.com>
Date: Sun, 27 Jun 2021 06:11:03 +1000
Subject: [PATCH] Prevent NPEs in /powertool (#4276)

This PR fixes a long-standing bug where using the `a:` or `r:` modes in `/powertool` with no commands already set on the item would result in an NPE. To prevent this, the powertool command list is now immediately initialized if it doesn't exist upon retrieval.
---
 .../essentials/commands/Commandpowertool.java      | 14 +++++---------
 1 file changed, 5 insertions(+), 9 deletions(-)

diff --git a/Essentials/src/main/java/com/earth2me/essentials/commands/Commandpowertool.java b/Essentials/src/main/java/com/earth2me/essentials/commands/Commandpowertool.java
index 88b7a0c4f..d6ba3fa0e 100644
--- a/Essentials/src/main/java/com/earth2me/essentials/commands/Commandpowertool.java
+++ b/Essentials/src/main/java/com/earth2me/essentials/commands/Commandpowertool.java
@@ -8,7 +8,6 @@ import org.bukkit.Material;
 import org.bukkit.Server;
 import org.bukkit.inventory.ItemStack;
 
-import java.util.ArrayList;
 import java.util.Collections;
 import java.util.List;
 import java.util.Locale;
@@ -52,10 +51,11 @@ public class Commandpowertool extends EssentialsCommand {
         }
 
         final String itemName = itemStack.getType().toString().toLowerCase(Locale.ENGLISH).replaceAll("_", " ");
-        List<String> powertools = user.getPowertool(itemStack);
+        final List<String> powertools = user.getPowertool(itemStack) != null ? user.getPowertool(itemStack) : Lists.newArrayList();
+
         if (command != null && !command.isEmpty()) {
             if (command.equalsIgnoreCase("l:")) {
-                if (powertools == null || powertools.isEmpty()) {
+                if (powertools.isEmpty()) {
                     throw new Exception(tl("powerToolListEmpty", itemName));
                 } else {
                     sender.sendMessage(tl("powerToolList", StringUtil.joinList(powertools), itemName));
@@ -79,20 +79,16 @@ public class Commandpowertool extends EssentialsCommand {
                     if (powertools.contains(command)) {
                         throw new Exception(tl("powerToolAlreadySet", command, itemName));
                     }
-                } else if (powertools != null && !powertools.isEmpty()) {
+                } else if (!powertools.isEmpty()) {
                     // Replace all commands with this one
                     powertools.clear();
-                } else {
-                    powertools = new ArrayList<>();
                 }
 
                 powertools.add(command);
                 sender.sendMessage(tl("powerToolAttach", StringUtil.joinList(powertools), itemName));
             }
         } else {
-            if (powertools != null) {
-                powertools.clear();
-            }
+            powertools.clear();
             sender.sendMessage(tl("powerToolRemoveAll", itemName));
         }