Fix minecraft:reload deleting commands on Paper-1.20.6-65 and beyond

Author: DerEchtePilz

commandapi-platforms/commandapi-bukkit/commandapi-bukkit-core/src/main/java/dev/jorel/commandapi/CommandAPIBukkit.java

@@ -176,6 +176,10 @@ private void checkDependencies() {
 		commandRegistrationStrategy = createCommandRegistrationStrategy();
 	}
 
+	protected CommandRegistrationStrategy<Source> getCommandRegistrationStrategy() {
+		return commandRegistrationStrategy;
+	}
+
 	@Override
 	public void onEnable() {
 		JavaPlugin plugin = config.getPlugin();

commandapi-platforms/commandapi-bukkit/commandapi-bukkit-core/src/main/java/dev/jorel/commandapi/CommandRegistrationStrategy.java

@@ -82,4 +82,6 @@ protected static boolean isThisTheCommandButNamespaced(String commandName, Strin
 	public abstract LiteralCommandNode<Source> registerCommandNode(LiteralArgumentBuilder<Source> node, String namespace);
 
 	public abstract void unregister(String commandName, boolean unregisterNamespaces, boolean unregisterBukkit);
+
+	public abstract void preReloadDataPacks();
 }

commandapi-platforms/commandapi-bukkit/commandapi-bukkit-core/src/main/java/dev/jorel/commandapi/PaperCommandRegistration.java

@@ -2,25 +2,31 @@
 
 import com.mojang.brigadier.CommandDispatcher;
 import com.mojang.brigadier.builder.LiteralArgumentBuilder;
+import com.mojang.brigadier.tree.CommandNode;
 import com.mojang.brigadier.tree.LiteralCommandNode;
 
+import java.util.ArrayList;
 import java.util.List;
+import java.util.function.Supplier;
 
 /**
- * Handles logic for registering commands after Paper build 65, where https://github.com/PaperMC/Paper/pull/8235
+ * Handles logic for registering commands after Paper build 65, where <a href="https://github.com/PaperMC/Paper/pull/8235">https://github.com/PaperMC/Paper/pull/8235</a>
  * changed a bunch of the behind-the-scenes logic.
  */
 public class PaperCommandRegistration<Source> extends CommandRegistrationStrategy<Source> {
 	// References to necessary objects
-	private final CommandDispatcher<Source> brigadierDispatcher;
+	private final Supplier<CommandDispatcher<Source>> getBrigadierDispatcher;
 
-	public PaperCommandRegistration(CommandDispatcher<Source> brigadierDispatcher) {
-		this.brigadierDispatcher = brigadierDispatcher;
+	// Store registered commands nodes for eventual reloads
+	private final List<LiteralCommandNode<Source>> registeredNodes = new ArrayList<>();
+
+	public PaperCommandRegistration(Supplier<CommandDispatcher<Source>> getBrigadierDispatcher) {
+		this.getBrigadierDispatcher = getBrigadierDispatcher;
 	}
 
 	@Override
 	public CommandDispatcher<Source> getBrigadierDispatcher() {
-		return brigadierDispatcher;
+		return getBrigadierDispatcher.get();
 	}
 
 	@Override
@@ -35,20 +41,32 @@ public void postCommandRegistration(RegisteredCommand registeredCommand, Literal
 
 	@Override
 	public LiteralCommandNode<Source> registerCommandNode(LiteralArgumentBuilder<Source> node, String namespace) {
-		LiteralCommandNode<Source> builtNode = brigadierDispatcher.register(node);
+		LiteralCommandNode<Source> commandNode = getBrigadierDispatcher.get().register(node);
+		LiteralCommandNode<Source> namespacedCommandNode = CommandAPIHandler.getInstance().namespaceNode(commandNode, namespace);
+
+		// Add to registered command nodes
+		registeredNodes.add(commandNode);
+		registeredNodes.add(namespacedCommandNode);
 
 		// Namespace is not empty on Bukkit forks
-		brigadierDispatcher.getRoot().addChild(CommandAPIHandler.getInstance().namespaceNode(builtNode, namespace));
+		getBrigadierDispatcher.get().getRoot().addChild(namespacedCommandNode);
 
-		return builtNode;
+		return commandNode;
 	}
 
 	@Override
 	public void unregister(String commandName, boolean unregisterNamespaces, boolean unregisterBukkit) {
 		// Remove nodes from the  dispatcher
-		removeBrigadierCommands(brigadierDispatcher, commandName, unregisterNamespaces, c -> true);
+		removeBrigadierCommands(getBrigadierDispatcher.get(), commandName, unregisterNamespaces, c -> true);
 
 		// Update the dispatcher file
 		CommandAPIHandler.getInstance().writeDispatcherToFile();
 	}
+
+	@Override
+	public void preReloadDataPacks() {
+		for (LiteralCommandNode<Source> commandNode : registeredNodes) {
+			getBrigadierDispatcher.get().getRoot().addChild(commandNode);
+		}
+	}
 }

commandapi-platforms/commandapi-bukkit/commandapi-bukkit-core/src/main/java/dev/jorel/commandapi/PaperImplementations.java

@@ -58,6 +58,9 @@ public void registerReloadHandler(Plugin plugin) {
 
 				@EventHandler
 				public void onServerReloadResources(ServerResourcesReloadedEvent event) {
+					// This event is called after Paper is done with everything command related
+					// which means we can put commands back
+					CommandAPIBukkit.get().getCommandRegistrationStrategy().preReloadDataPacks();
 					CommandAPI.logNormal("/minecraft:reload detected. Reloading CommandAPI commands!");
 					nmsInstance.reloadDataPacks();
 				}

commandapi-platforms/commandapi-bukkit/commandapi-bukkit-core/src/main/java/dev/jorel/commandapi/SpigotCommandRegistration.java

@@ -134,7 +134,6 @@ private void fixPermissions() {
 
 	@Override
 	public void postCommandRegistration(RegisteredCommand registeredCommand, LiteralCommandNode<Source> resultantNode, List<LiteralCommandNode<Source>> aliasNodes) {
-
 		if (!CommandAPI.canRegister()) {
 			// Usually, when registering commands during server startup, we can just put our commands into the
 			// `net.minecraft.server.MinecraftServer#vanillaCommandDispatcher` and leave it. As the server finishes setup,
@@ -297,4 +296,9 @@ public void unregister(String commandName, boolean unregisterNamespaces, boolean
 				c -> !unregisterBukkit ^ commandAPIBukkit.isBukkitCommandWrapper(c));
 		}
 	}
+
+	@Override
+	public void preReloadDataPacks() {
+		// Nothing to do
+	}
 }

commandapi-platforms/commandapi-bukkit/commandapi-bukkit-nms/commandapi-bukkit-1.20.5/src/main/java/dev/jorel/commandapi/nms/NMS_1_20_R4.java

@@ -905,7 +905,7 @@ public CommandRegistrationStrategy<CommandSourceStack> createCommandRegistration
 				() -> this.<MinecraftServer>getMinecraftServer().getCommands().getDispatcher()
 			);
 		} else {
-			return new PaperCommandRegistration<>(this.<MinecraftServer>getMinecraftServer().getCommands().getDispatcher());
+			return new PaperCommandRegistration<>(() -> this.<MinecraftServer>getMinecraftServer().getCommands().getDispatcher());
 		}
 	}