feat(pumpkin): add /reload command (#2960)

Adds the vanilla /reload command (permission level 2), which reloads
the server's datapacks: it re-reads the enabled packs, re-runs the
#minecraft:load function tag and pushes the rebuilt recipes to every
player, through the same Server::reload_datapacks path /datapack
enable and /datapack disable already use.

Feedback follows Vanilla and is sent before the reload starts, so it
arrives even though reloading takes a moment.

Co-authored-by: Mcxiaocaibug <Mcxiaocaibug@users.noreply.github.com>

crates/pumpkin/src/command/commands/mod.rs

@@ -55,6 +55,7 @@ mod plugins;
 mod pumpkin;
 mod random;
 mod recipe;
+mod reload;
 mod ride;
 mod rotate;
 mod saveall;
@@ -187,6 +188,7 @@ pub fn default_dispatcher(
     forceload::register(&mut dispatcher, registry);
     ride::register(&mut dispatcher, registry);
     recipe::register(&mut dispatcher, registry);
+    reload::register(&mut dispatcher, registry);
     help::register(&mut dispatcher, registry);
     kill::register(&mut dispatcher, registry);
     op::register(&mut dispatcher, registry);

crates/pumpkin/src/command/commands/reload.rs

@@ -0,0 +1,53 @@
+use pumpkin_data::translation;
+use pumpkin_util::PermissionLvl;
+use pumpkin_util::permission::{Permission, PermissionDefault, PermissionRegistry};
+use pumpkin_util::text::TextComponent;
+
+use crate::command::argument_builder::{ArgumentBuilder, command};
+use crate::command::context::command_context::CommandContext;
+use crate::command::node::dispatcher::CommandDispatcher;
+use crate::command::node::{CommandExecutor, CommandExecutorResult};
+
+const DESCRIPTION: &str = "Reloads the server's datapacks.";
+const PERMISSION: &str = "minecraft:command.reload";
+
+struct ReloadExecutor;
+
+impl CommandExecutor for ReloadExecutor {
+    fn execute<'a>(&'a self, context: &'a CommandContext) -> CommandExecutorResult<'a> {
+        Box::pin(async move {
+            // Vanilla announces the reload before doing it, so the feedback
+            // arrives even though reloading takes a moment.
+            context
+                .source
+                .send_feedback(
+                    TextComponent::translate_cross(
+                        translation::java::COMMANDS_RELOAD_SUCCESS,
+                        translation::java::COMMANDS_RELOAD_SUCCESS,
+                        [],
+                    ),
+                    true,
+                )
+                .await;
+
+            let server = context.server();
+            server.reload_datapacks(server).await;
+
+            Ok(0)
+        })
+    }
+}
+
+pub fn register(dispatcher: &mut CommandDispatcher, registry: &PermissionRegistry) {
+    registry.register_permission_or_panic(Permission::new(
+        PERMISSION,
+        DESCRIPTION,
+        PermissionDefault::Op(PermissionLvl::Two),
+    ));
+
+    dispatcher.register(
+        command("reload", DESCRIPTION)
+            .requires(PERMISSION)
+            .executes(ReloadExecutor),
+    );
+}