feat: Allow opening config with just /firm

src/main/java/moe/nea/firmament/mixins/RedirectWithoutSubCommands.java

@@ -0,0 +1,42 @@
+package moe.nea.firmament.mixins;
+
+import com.llamalad7.mixinextras.sugar.Local;
+import com.mojang.brigadier.CommandDispatcher;
+import com.mojang.brigadier.ParseResults;
+import com.mojang.brigadier.StringReader;
+import com.mojang.brigadier.context.CommandContextBuilder;
+import com.mojang.brigadier.tree.CommandNode;
+import moe.nea.firmament.util.ErrorUtil;
+import org.spongepowered.asm.mixin.Mixin;
+import org.spongepowered.asm.mixin.injection.At;
+import org.spongepowered.asm.mixin.injection.Inject;
+import org.spongepowered.asm.mixin.injection.callback.CallbackInfoReturnable;
+
+import java.util.HashSet;
+
+@Mixin(CommandDispatcher.class)
+public class RedirectWithoutSubCommands<S> {
+	@Inject(
+		method = "parseNodes",
+		at = @At(
+			value = "INVOKE",
+			target = "Lcom/mojang/brigadier/context/CommandContextBuilder;withCommand(Lcom/mojang/brigadier/Command;)Lcom/mojang/brigadier/context/CommandContextBuilder;",
+			shift = At.Shift.AFTER
+		)
+	)
+	private void injectCommandForRedirects(
+		CommandNode<S> node, StringReader originalReader, CommandContextBuilder<S> contextSoFar, CallbackInfoReturnable<ParseResults<S>> cir,
+		@Local(index = 10) CommandContextBuilder<S> context,
+		@Local(index = 9) CommandNode<S> child
+	) {
+		var p = child;
+		var set = new HashSet<>();
+		if (context.getCommand() == null && p.getRedirect() != null) {
+			p = p.getRedirect();
+			context.withCommand(p.getCommand());
+			if (!set.add(p)) {
+				ErrorUtil.INSTANCE.softError("Redirect circle detected in " + p);
+			}
+		}
+	}
+}