Exception handling in commands

By: Dinnerbone <dinnerbone@dinnerbone.com>

paper-api/src/main/java/org/bukkit/command/CommandException.java

@@ -0,0 +1,27 @@
+
+package org.bukkit.command;
+
+/**
+ * Thrown when an unhandled exception occurs during the execution of a Command
+ */
+public class CommandException extends RuntimeException {
+
+    /**
+     * Creates a new instance of <code>CommandException</code> without detail message.
+     */
+    public CommandException() {
+    }
+
+
+    /**
+     * Constructs an instance of <code>CommandException</code> with the specified detail message.
+     * @param msg the detail message.
+     */
+    public CommandException(String msg) {
+        super(msg);
+    }
+
+    public CommandException(String msg, Throwable cause) {
+        super(msg, cause);
+    }
+}

paper-api/src/main/java/org/bukkit/command/CommandMap.java

@@ -1,7 +1,6 @@
 package org.bukkit.command;
 
 import java.util.List;
-import org.bukkit.entity.Player;
 
 public interface CommandMap {
     /**
@@ -19,10 +18,12 @@ public interface CommandMap {
      */
     public boolean register(String label, String fallbackPrefix, Command command);
 
-    /** Looks for the requested command and executes it if found.
+    /**
+     * Looks for the requested command and executes it if found.
      *
-     *   @param cmdLine command + arguments. Example: "/test abc 123"
-     *   @return targetFound returns false if no target is found.
+     * @param cmdLine command + arguments. Example: "/test abc 123"
+     * @return targetFound returns false if no target is found.
+     * @throws CommandException Thrown when the executor for the given command fails with an unhandled exception
      */
     public boolean dispatch(CommandSender sender, String cmdLine);
 

paper-api/src/main/java/org/bukkit/command/PluginCommand.java

@@ -1,7 +1,6 @@
 package org.bukkit.command;
 
 import org.bukkit.ChatColor;
-import org.bukkit.entity.Player;
 import org.bukkit.plugin.Plugin;
 
 public final class PluginCommand extends Command {
@@ -14,7 +13,14 @@ public final class PluginCommand extends Command {
     }
 
     public boolean execute(CommandSender sender, String commandLabel, String[] args) {
-        boolean cmdSuccess = owningPlugin.onCommand(sender, this, commandLabel, args);
+        boolean cmdSuccess = false;
+        
+        try {
+            owningPlugin.onCommand(sender, this, commandLabel, args);
+        } catch (Throwable ex) {
+            throw new CommandException("Unhandled exception executing command '" + commandLabel + "' in plugin " + owningPlugin.getDescription().getFullName(), ex);
+        }
+
         if (!cmdSuccess && !usageMessage.isEmpty()) {
             String tmpMsg = usageMessage.replace("<command>", commandLabel);
             String[] usageLines = tmpMsg.split("\\n");

paper-api/src/main/java/org/bukkit/command/SimpleCommandMap.java

@@ -8,7 +8,6 @@ import java.util.Map;
 import org.bukkit.ChatColor;
 import org.bukkit.Server;
 
-import org.bukkit.entity.Player;
 import org.bukkit.plugin.Plugin;
 import org.bukkit.plugin.PluginDescriptionFile;
 
@@ -74,7 +73,13 @@ public final class SimpleCommandMap implements CommandMap {
         Command target = knownCommands.get(sentCommandLabel);
         boolean isRegisteredCommand = (target != null);
         if (isRegisteredCommand) {
-            target.execute(sender, sentCommandLabel, args);
+            try {
+                target.execute(sender, sentCommandLabel, args);
+            } catch (CommandException ex) {
+                throw ex;
+            } catch (Throwable ex) {
+                throw new CommandException("Unhandled exception executing '" + commandLine + "' in " + target, ex);
+            }
         }
         return isRegisteredCommand;
     }