From a308504bd0a184f8e568e063143a3df4ec10fefb Mon Sep 17 00:00:00 2001
From: Minecrell <dev@minecrell.net>
Date: Thu, 21 Sep 2017 19:41:20 +0200
Subject: [PATCH] Add workaround for plugins modifying the parent of the plugin
 logger

Essentials uses a custom logger name ("Essentials") instead of the
plugin logger. Log messages are redirected to the plugin logger by
setting the parent of the "Essentials" logger to the plugin logger.

With our changes, the plugin logger is now also called "Essentials",
resulting in an infinite loop. Make sure plugins can't change the
parent of the plugin logger to avoid this.

diff --git a/src/main/java/com/destroystokyo/paper/utils/PaperPluginLogger.java b/src/main/java/com/destroystokyo/paper/utils/PaperPluginLogger.java
new file mode 100644
index 00000000..1c93cf30
--- /dev/null
+++ b/src/main/java/com/destroystokyo/paper/utils/PaperPluginLogger.java
@@ -0,0 +1,27 @@
+package com.destroystokyo.paper.utils;
+
+import org.bukkit.plugin.PluginDescriptionFile;
+
+import java.util.logging.LogManager;
+import java.util.logging.Logger;
+
+/**
+ * Prevents plugins (e.g. Essentials) from changing the parent of the plugin logger.
+ */
+public class PaperPluginLogger extends Logger {
+
+    public PaperPluginLogger(PluginDescriptionFile description) {
+        super(description.getPrefix() != null ? description.getPrefix() : description.getName(), null);
+        LogManager.getLogManager().addLogger(this);
+    }
+
+    @Override
+    public void setParent(Logger parent) {
+        if (getParent() != null) {
+            warning("Ignoring attempt to change parent of plugin logger");
+        } else {
+            super.setParent(parent);
+        }
+    }
+
+}
diff --git a/src/main/java/org/bukkit/plugin/java/PluginClassLoader.java b/src/main/java/org/bukkit/plugin/java/PluginClassLoader.java
index b2cbf9e4..7a95239a 100644
--- a/src/main/java/org/bukkit/plugin/java/PluginClassLoader.java
+++ b/src/main/java/org/bukkit/plugin/java/PluginClassLoader.java
@@ -59,6 +59,8 @@ public final class PluginClassLoader extends URLClassLoader { // Spigot
         this.dataFolder = dataFolder;
         this.file = file;
 
+        new com.destroystokyo.paper.utils.PaperPluginLogger(description); // Paper - Register logger early
+
         try {
             Class<?> jarClass;
             try {
-- 
2.14.1