From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
From: Minecrell <minecrell@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 0000000000000000000000000000000000000000..087ee57fe5485bc760fadd45a176d4d90a18f9f8
--- /dev/null
+++ b/src/main/java/com/destroystokyo/paper/utils/PaperPluginLogger.java
@@ -0,0 +1,48 @@
+package com.destroystokyo.paper.utils;
+
+import io.papermc.paper.plugin.configuration.PluginMeta;
+import org.bukkit.plugin.PluginDescriptionFile;
+
+import java.util.logging.Level;
+import java.util.logging.LogManager;
+import java.util.logging.Logger;
+import org.jetbrains.annotations.NotNull;
+
+/**
+ * Prevents plugins (e.g. Essentials) from changing the parent of the plugin logger.
+ */
+public class PaperPluginLogger extends Logger {
+
+    @Deprecated(forRemoval = true)
+    @NotNull
+    public static Logger getLogger(@NotNull PluginDescriptionFile description) {
+        return getLogger((PluginMeta) description);
+    }
+
+    @NotNull
+    public static Logger getLogger(@NotNull PluginMeta meta) {
+        Logger logger = new PaperPluginLogger(meta);
+        if (!LogManager.getLogManager().addLogger(logger)) {
+            // Disable this if it's going to happen across reloads anyways...
+            //logger.log(Level.WARNING, "Could not insert plugin logger - one was already found: {}", LogManager.getLogManager().getLogger(this.getName()));
+            logger = LogManager.getLogManager().getLogger(meta.getLoggerPrefix() != null ? meta.getLoggerPrefix() : meta.getName());
+        }
+
+        return logger;
+    }
+
+    private PaperPluginLogger(@NotNull PluginMeta meta) {
+        super(meta.getLoggerPrefix() != null ? meta.getLoggerPrefix() : meta.getName(), null);
+    }
+
+    @Override
+    public void setParent(@NotNull Logger parent) {
+        if (getParent() != null) {
+            warning("Ignoring attempt to change parent of plugin logger");
+        } else {
+            this.log(Level.FINE, "Setting plugin logger parent to {0}", parent);
+            super.setParent(parent);
+        }
+    }
+
+}
diff --git a/src/main/java/org/bukkit/plugin/java/JavaPlugin.java b/src/main/java/org/bukkit/plugin/java/JavaPlugin.java
index 71c8d2345eef6895edb8d210553ec3cddd9c76d0..6d31f3a2569ae9c522a5e6cddd38ac8f252f1bfe 100644
--- a/src/main/java/org/bukkit/plugin/java/JavaPlugin.java
+++ b/src/main/java/org/bukkit/plugin/java/JavaPlugin.java
@@ -44,7 +44,7 @@ public abstract class JavaPlugin extends PluginBase {
     private boolean naggable = true;
     private FileConfiguration newConfig = null;
     private File configFile = null;
-    private Logger logger = null; // Paper - PluginLogger -> Logger
+    public Logger logger = null; // Paper - PluginLogger -> Logger, public
 
     public JavaPlugin() {
         // Paper start
@@ -302,7 +302,11 @@ public abstract class JavaPlugin extends PluginBase {
         this.classLoader = classLoader;
         this.configFile = new File(dataFolder, "config.yml");
         this.pluginMeta = configuration; // Paper
-        this.logger = Logger.getLogger(description.getPrefix() != null ? description.getPrefix() : description.getName()); // Paper - Handle plugin prefix in implementation
+        // Paper start
+        if (this.logger == null) {
+            this.logger = com.destroystokyo.paper.utils.PaperPluginLogger.getLogger(this.description);
+        }
+        // Paper end
     }
 
     /**
diff --git a/src/main/java/org/bukkit/plugin/java/PluginClassLoader.java b/src/main/java/org/bukkit/plugin/java/PluginClassLoader.java
index c42663a2ae98fda6dcf2ab6ac899cc6238bce65f..ed2492ce51097dd0c2ba72e7b9449561a73ea7e3 100644
--- a/src/main/java/org/bukkit/plugin/java/PluginClassLoader.java
+++ b/src/main/java/org/bukkit/plugin/java/PluginClassLoader.java
@@ -64,7 +64,7 @@ public final class PluginClassLoader extends URLClassLoader implements io.paperm
         this.url = file.toURI().toURL();
         this.libraryLoader = libraryLoader;
 
-
+        this.logger = com.destroystokyo.paper.utils.PaperPluginLogger.getLogger(description); // Paper - Register logger early
         // Paper start
         this.classLoaderGroup = io.papermc.paper.plugin.provider.classloader.PaperClassLoaderStorage.instance().registerSpigotGroup(this); // Paper
         // Paper end
@@ -247,6 +247,7 @@ public final class PluginClassLoader extends URLClassLoader implements io.paperm
         pluginState = new IllegalStateException("Initial initialization");
         this.pluginInit = javaPlugin;
 
+        javaPlugin.logger = this.logger; // Paper - set logger
         javaPlugin.init(null, org.bukkit.Bukkit.getServer(), description, dataFolder, file, this); // Paper
     }