Show an error message when recipes are not synced from the server

Author: mezz

Common/src/main/resources/assets/jei/lang/en_us.json

@@ -311,6 +311,7 @@
   "jei.message.config.folder": "Or click here to open the JEI config folder instead",
   "jei.message.copy.recipe.id.success": "The following recipe ID was copied to the clipboard: %s",
   "jei.message.copy.recipe.id.failure": "Failed to copy the recipe ID to the clipboard because the ID is unknown",
+  "jei.message.missing.recipes.from.server": "JEI is missing recipes. Please install JEI on the server to sync recipes to the client.\nSince Minecraft 1.21.2, recipes are stored on the server and not the client.",
 
   "_comment": "Key Names",
   "jei.key.combo.shift": "SHIFT + %s",

Library/src/main/java/mezz/jei/library/plugins/vanilla/VanillaPlugin.java

@@ -242,6 +242,11 @@ public void registerVanillaCategoryExtensions(IVanillaCategoryExtensionRegistrat
 
 	@Override
 	public void registerRecipes(IRecipeRegistration registration) {
+		RecipeMap clientSyncedRecipes = Internal.getClientSyncedRecipes();
+		if (clientSyncedRecipes.values().isEmpty()) {
+			return;
+		}
+
 		ErrorUtil.checkNotNull(craftingCategory, "craftingCategory");
 		ErrorUtil.checkNotNull(stonecuttingCategory, "stonecuttingCategory");
 		ErrorUtil.checkNotNull(furnaceCategory, "furnaceCategory");
@@ -254,7 +259,6 @@ public void registerRecipes(IRecipeRegistration registration) {
 		IVanillaRecipeFactory vanillaRecipeFactory = registration.getVanillaRecipeFactory();
 		IJeiHelpers jeiHelpers = registration.getJeiHelpers();
 
-		RecipeMap clientSyncedRecipes = Internal.getClientSyncedRecipes();
 		VanillaRecipes vanillaRecipes = new VanillaRecipes(clientSyncedRecipes);
 
 		var craftingRecipes = vanillaRecipes.getCraftingRecipes(craftingCategory);

Library/src/main/java/mezz/jei/library/startup/JeiStarter.java

@@ -15,8 +15,10 @@
 import mezz.jei.common.config.file.FileWatcher;
 import mezz.jei.common.config.file.IConfigSchemaBuilder;
 import mezz.jei.common.platform.Services;
+import mezz.jei.common.util.ChatUtil;
 import mezz.jei.common.util.ErrorUtil;
 import mezz.jei.common.util.RegistryUtil;
+import mezz.jei.common.util.Translator;
 import mezz.jei.core.util.LoggedTimer;
 import mezz.jei.library.color.ColorHelper;
 import mezz.jei.library.config.ColorNameConfig;
@@ -35,8 +37,11 @@
 import mezz.jei.library.recipes.RecipeManager;
 import mezz.jei.library.runtime.JeiHelpers;
 import mezz.jei.library.runtime.JeiRuntime;
+import net.minecraft.ChatFormatting;
 import net.minecraft.client.Minecraft;
+import net.minecraft.client.player.LocalPlayer;
 import net.minecraft.core.RegistryAccess;
+import net.minecraft.world.item.crafting.RecipeMap;
 import org.apache.logging.log4j.LogManager;
 import org.apache.logging.log4j.Logger;
 
@@ -184,6 +189,16 @@ public void start() {
 		Internal.setRuntime(jeiRuntime);
 
 		totalTime.stop();
+
+		RecipeMap clientSyncedRecipes = Internal.getClientSyncedRecipes();
+		if (clientSyncedRecipes.values().isEmpty()) {
+			String message = Translator.translateToLocal("jei.message.missing.recipes.from.server");
+			LocalPlayer player = minecraft.player;
+			if (player != null) {
+				ChatUtil.writeChatMessage(player, message, ChatFormatting.RED);
+			}
+			LOGGER.error(message);
+		}
 	}
 
 	public void stop() {