fix: reset nickname when player changes Minecraft account name

Essentials/src/main/java/com/earth2me/essentials/EssentialsPlayerListener.java

@@ -420,6 +420,12 @@ private void joinFlow(final User user, final long currentTime, final String mess
 
         final String lastAccountName = user.getLastAccountName(); // For comparison
         user.setLastAccountName(user.getBase().getName());
+
+        // If the Minecraft account name changed, reset the nickname so the old one doesn't persist
+        if (ess.getSettings().isResetNickOnNameChange() && lastAccountName != null && !lastAccountName.equals(user.getBase().getName()) && user.getNickname() != null) {
+            user.setNickname(null);
+        }
+
         user.setLastLogin(currentTime);
         user.setDisplayNick();
         updateCompass(user);

Essentials/src/main/java/com/earth2me/essentials/IEssentials.java

@@ -94,6 +94,8 @@ public interface IEssentials extends Plugin {
 
     RandomTeleport getRandomTeleport();
 
+    boolean isResetNickOnNameChange();
+
     UpdateChecker getUpdateChecker();
 
     BukkitTask runTaskAsynchronously(Runnable run);

Essentials/src/main/java/com/earth2me/essentials/Settings.java

@@ -147,6 +147,7 @@ public class Settings implements net.ess3.api.ISettings {
     private boolean logCommandBlockCommands;
     private boolean logConsoleCommands;
     private Set<Predicate<String>> nickBlacklist;
+    private boolean resetNickOnNameChange = false;
     private double maxProjectileSpeed;
     private boolean removeEffectsOnHeal;
     private Map<String, String> worldAliases;
@@ -508,11 +509,20 @@ private String _getNicknamePrefix() {
         return config.getString("nickname-prefix", "~");
     }
 
+    private boolean _resetNickOnNameChange() {
+        return config.getBoolean("reset-nick-on-name-change", false);
+    }
+
     @Override
     public String getNicknamePrefix() {
         return nicknamePrefix;
     }
 
+    @Override
+    public boolean isResetNickOnNameChange() {
+        return resetNickOnNameChange;
+    }
+
     @Override
     public double getTeleportCooldown() {
         return config.getDouble("teleport-cooldown", 0);
@@ -886,6 +896,7 @@ public void reloadConfig() {
         }
 
         nicknamePrefix = _getNicknamePrefix();
+        resetNickOnNameChange = _resetNickOnNameChange();
         operatorColor = _getOperatorColor();
         changePlayerListName = _changePlayerListName();
         configDebug = _isDebug();

Essentials/src/main/resources/config.yml

@@ -51,6 +51,10 @@ nick-blacklist:
 # For example, if "&6Notch" has 7 characters (2 are part of a color code), a length of 5 is used when this option is set to true.
 ignore-colors-in-max-nick-length: false
 
+# When this option is enabled, any nickname set by a player will be reset when their Minecraft account name changes.
+# This prevents old nicknames (including RGB-formatted ones) from persisting after a name change.
+reset-nick-on-name-change: false
+
 # When this option is enabled, display names for hidden players will not be shown. This prevents players from being
 # able to see that they are online while vanished.
 hide-displayname-in-vanish: true