From e1c1da199e6d4e1e5470359159a2038b46357bac Mon Sep 17 00:00:00 2001
From: games647 <games647@users.noreply.github.com>
Date: Thu, 2 Dec 2021 14:15:57 +0100
Subject: [PATCH] Search SL4J JDK provider in our own classpath

Using the previous behavior it would look for the service file and provider
in the server jar. First it requires relocating the service file to our JDK
provider and let the service only be queryable from our plugin jar.

Fixes #668

Search SL4J JDK provider in our own classpath

Using the previous behavior it would look for the service file and provider
in the server jar. First it requires relocating the service file to our JDK
provider and let the service only be queryable from our plugin jar.

Fixes #668
---
 bukkit/pom.xml                                | 10 ++++++---
 .../fastlogin/bukkit/FastLoginBukkit.java     | 10 ++++-----
 bungee/pom.xml                                | 14 +++++++++++-
 .../fastlogin/bungee/FastLoginBungee.java     |  2 +-
 core/pom.xml                                  | 20 +++++++----------
 .../games647/fastlogin/core/CommonUtil.java   | 22 ++++++++++++++++++-
 6 files changed, 55 insertions(+), 23 deletions(-)

diff --git a/bukkit/pom.xml b/bukkit/pom.xml
index 7ee59060..26a0f975 100644
--- a/bukkit/pom.xml
+++ b/bukkit/pom.xml
@@ -77,6 +77,11 @@
                             <shadedPattern>fastlogin.paperlib</shadedPattern>
                         </relocation>
                     </relocations>
+                    <!-- Rename the service file too to let SLF4J api find our own relocated jdk logger -->
+                    <!-- Located in META-INF/services -->
+                    <transformers>
+                        <transformer implementation="org.apache.maven.plugins.shade.resource.ServicesResourceTransformer"/>
+                    </transformers>
                 </configuration>
                 <executions>
                     <execution>
@@ -147,9 +152,9 @@
 
         <!-- PaperSpigot API for correcting usercache usage -->
         <dependency>
-            <groupId>com.destroystokyo.paper</groupId>
+            <groupId>io.papermc.paper</groupId>
             <artifactId>paper-api</artifactId>
-            <version>1.15.2-R0.1-SNAPSHOT</version>
+            <version>1.18-R0.1-SNAPSHOT</version>
             <scope>provided</scope>
         </dependency>
 
@@ -158,7 +163,6 @@
             <groupId>io.papermc</groupId>
             <artifactId>paperlib</artifactId>
             <version>1.0.7</version>
-            <scope>compile</scope>
         </dependency>
 
         <!--Library for listening and sending Minecraft packets-->
diff --git a/bukkit/src/main/java/com/github/games647/fastlogin/bukkit/FastLoginBukkit.java b/bukkit/src/main/java/com/github/games647/fastlogin/bukkit/FastLoginBukkit.java
index c3171bc0..1450fc17 100644
--- a/bukkit/src/main/java/com/github/games647/fastlogin/bukkit/FastLoginBukkit.java
+++ b/bukkit/src/main/java/com/github/games647/fastlogin/bukkit/FastLoginBukkit.java
@@ -79,7 +79,7 @@ public class FastLoginBukkit extends JavaPlugin implements PlatformPlugin<Comman
     private PremiumPlaceholder premiumPlaceholder;
 
     public FastLoginBukkit() {
-        this.logger = CommonUtil.createLoggerFromJDK(getLogger());
+        this.logger = CommonUtil.initializeLoggerService(getLogger());
         this.scheduler = new BukkitScheduler(this, logger, getThreadFactory());
     }
 
@@ -101,7 +101,7 @@ public class FastLoginBukkit extends JavaPlugin implements PlatformPlugin<Comman
 
         bungeeManager = new BungeeManager(this);
         bungeeManager.initialize();
-        
+
         PluginManager pluginManager = getServer().getPluginManager();
         if (bungeeManager.isEnabled()) {
             markInitialized();
@@ -153,7 +153,7 @@ public class FastLoginBukkit extends JavaPlugin implements PlatformPlugin<Comman
         if (getServer().getPluginManager().getPlugin("Geyser-Spigot") != null) {
             geyserService = new GeyserService(GeyserConnector.getInstance(), core);
         }
-        
+
         if (getServer().getPluginManager().getPlugin("floodgate") != null) {
             floodgateService = new FloodgateService(FloodgateApi.getInstance(), core);
 
@@ -272,7 +272,7 @@ public class FastLoginBukkit extends JavaPlugin implements PlatformPlugin<Comman
     public void sendMessage(CommandSender receiver, String message) {
         receiver.sendMessage(message);
     }
-    
+
 	/**
 	 * Checks if a plugin is installed on the server
 	 * @param name the name of the plugin
@@ -301,7 +301,7 @@ public class FastLoginBukkit extends JavaPlugin implements PlatformPlugin<Comman
     }
 
     /**
-     * Send warning messages to log if incompatible plugins are used  
+     * Send warning messages to log if incompatible plugins are used
      */
     private void dependencyWarnings() {
         if (isPluginInstalled("floodgate-bukkit")) {
diff --git a/bungee/pom.xml b/bungee/pom.xml
index b4859be1..1e53a654 100644
--- a/bungee/pom.xml
+++ b/bungee/pom.xml
@@ -70,6 +70,11 @@
                             <shadedPattern>fastlogin.slf4j</shadedPattern>
                         </relocation>
                     </relocations>
+                    <!-- Rename the service file too to let SLF4J api find our own relocated jdk logger -->
+                    <!-- Located in META-INF/services -->
+                    <transformers>
+                        <transformer implementation="org.apache.maven.plugins.shade.resource.ServicesResourceTransformer"/>
+                    </transformers>
                 </configuration>
                 <executions>
                     <execution>
@@ -120,8 +125,15 @@
         <dependency>
             <groupId>net.md-5</groupId>
             <artifactId>bungeecord-proxy</artifactId>
-            <version>1.16-R0.5-SNAPSHOT</version>
+            <version>1.18-R0.1-SNAPSHOT</version>
             <scope>provided</scope>
+            <!-- Use our own newer api version -->
+            <exclusions>
+                <exclusion>
+                    <groupId>org.slf4j</groupId>
+                    <artifactId>slf4j-api</artifactId>
+                </exclusion>
+            </exclusions>
         </dependency>
 
         <!-- Bedrock player bridge -->
diff --git a/bungee/src/main/java/com/github/games647/fastlogin/bungee/FastLoginBungee.java b/bungee/src/main/java/com/github/games647/fastlogin/bungee/FastLoginBungee.java
index b2a8648f..5346bf8b 100644
--- a/bungee/src/main/java/com/github/games647/fastlogin/bungee/FastLoginBungee.java
+++ b/bungee/src/main/java/com/github/games647/fastlogin/bungee/FastLoginBungee.java
@@ -81,7 +81,7 @@ public class FastLoginBungee extends Plugin implements PlatformPlugin<CommandSen
 
     @Override
     public void onEnable() {
-        logger = CommonUtil.createLoggerFromJDK(getLogger());
+        logger = CommonUtil.initializeLoggerService(getLogger());
         scheduler = new AsyncScheduler(logger, getThreadFactory());
 
         core = new FastLoginCore<>(this);
diff --git a/core/pom.xml b/core/pom.xml
index 4436d965..12ceed39 100644
--- a/core/pom.xml
+++ b/core/pom.xml
@@ -68,6 +68,14 @@
             <groupId>com.zaxxer</groupId>
             <artifactId>HikariCP</artifactId>
             <version>4.0.3</version>
+            <exclusions>
+                <!-- HikariCP uses an old version of this API that has a typo in the service interface -->
+                <!-- We will use the api provided by the jdk14 dependency -->
+                <exclusion>
+                    <groupId>org.slf4j</groupId>
+                    <artifactId>slf4j-api</artifactId>
+                </exclusion>
+            </exclusions>
         </dependency>
 
         <!--Logging framework implements slf4j which is required by hikari-->
@@ -149,17 +157,5 @@
             <artifactId>gson</artifactId>
             <version>2.8.9</version>
         </dependency>
-
-        <dependency>
-            <groupId>org.slf4j</groupId>
-            <artifactId>slf4j-api</artifactId>
-            <version>2.0.0-alpha5</version>
-        </dependency>
-        <dependency>
-            <groupId>org.slf4j</groupId>
-            <artifactId>slf4j-simple</artifactId>
-            <version>2.0.0-alpha5</version>
-            <scope>runtime</scope>
-        </dependency>
     </dependencies>
 </project>
diff --git a/core/src/main/java/com/github/games647/fastlogin/core/CommonUtil.java b/core/src/main/java/com/github/games647/fastlogin/core/CommonUtil.java
index f2803c4b..81b54b98 100644
--- a/core/src/main/java/com/github/games647/fastlogin/core/CommonUtil.java
+++ b/core/src/main/java/com/github/games647/fastlogin/core/CommonUtil.java
@@ -70,7 +70,24 @@ public class CommonUtil {
         return new String(chars);
     }
 
-    public static Logger createLoggerFromJDK(java.util.logging.Logger parent) {
+    /**
+     * This creates a SLF4J logger. In the process it initializes the SLF4J service provider. This method looks
+     * for the provider in the plugin jar instead of in the server jar when creating a Logger. The provider is only
+     * initialized once, so this method should be called early.
+     *
+     * The provider is bound to the service class `SLF4JServiceProvider`. Relocating this class makes it available
+     * for exclusive own usage. Other dependencies will use the relocated service too, and therefore will find the
+     * initialized provider.
+     *
+     * @param parent JDK logger
+     * @return slf4j logger
+     */
+    public static Logger initializeLoggerService(java.util.logging.Logger parent) {
+        // set the class loader to the plugin one to find our own SLF4J provider in the plugin jar and not in the global
+        ClassLoader oldLoader = Thread.currentThread().getContextClassLoader();
+
+        ClassLoader pluginLoader = CommonUtil.class.getClassLoader();
+        Thread.currentThread().setContextClassLoader(pluginLoader);
         try {
             parent.setLevel(Level.ALL);
 
@@ -82,6 +99,9 @@ public class CommonUtil {
             parent.log(Level.WARNING, "Cannot create slf4j logging adapter", reflectEx);
             parent.log(Level.WARNING, "Creating logger instance manually...");
             return LoggerFactory.getLogger(parent.getName());
+        } finally {
+            // restore previous class loader
+            Thread.currentThread().setContextClassLoader(oldLoader);
         }
     }