Fix backtanks getting incompatible enchants via smithing tables (#7057)

build.gradle

@@ -167,6 +167,11 @@ dependencies {
         jarJar.ranged(it, '[1.0,2.0)')
     }
 
+    compileOnly(annotationProcessor("io.github.llamalad7:mixinextras-common:0.4.1"))
+    implementation(jarJar("io.github.llamalad7:mixinextras-forge:0.4.1")) {
+        jarJar.ranged(it, "[0.4.1,)")
+    }
+
     implementation fg.deobf("com.tterrag.registrate:Registrate:${registrate_version}")
 
     compileOnly fg.deobf("dev.engine_room.flywheel:flywheel-forge-api-${flywheel_minecraft_version}:${flywheel_version}")

src/main/java/com/simibubi/create/foundation/mixin/SmithingMenuMixin.java

@@ -0,0 +1,45 @@
+package com.simibubi.create.foundation.mixin;
+
+import com.llamalad7.mixinextras.injector.ModifyExpressionValue;
+
+import com.simibubi.create.AllItems;
+import com.simibubi.create.content.equipment.armor.BacktankItem;
+
+import net.minecraft.world.inventory.SmithingMenu;
+
+import net.minecraft.world.item.ItemStack;
+
+import net.minecraft.world.item.enchantment.Enchantment;
+import net.minecraft.world.item.enchantment.EnchantmentHelper;
+
+import org.spongepowered.asm.mixin.Mixin;
+import org.spongepowered.asm.mixin.injection.At;
+
+import java.util.HashMap;
+import java.util.Map;
+
+@Mixin(SmithingMenu.class)
+public class SmithingMenuMixin {
+	// Only add enchantments to the backtank if it supports them
+	@ModifyExpressionValue(
+			method = "createResult",
+			at = @At(
+					value = "INVOKE",
+					target = "Lnet/minecraft/world/item/crafting/SmithingRecipe;assemble(Lnet/minecraft/world/Container;Lnet/minecraft/core/RegistryAccess;)Lnet/minecraft/world/item/ItemStack;"
+			)
+	)
+	private ItemStack create$preventUnbreakingOnBacktanks(ItemStack original) {
+		if (AllItems.COPPER_BACKTANK.is(original) || AllItems.NETHERITE_BACKTANK.is(original)) {
+			Map<Enchantment, Integer> enchantments = new HashMap<>();
+
+			EnchantmentHelper.getEnchantments(original).forEach((enchantment, level) -> {
+				if (enchantment.canEnchant(original))
+					enchantments.put(enchantment, level);
+			});
+
+			EnchantmentHelper.setEnchantments(enchantments, original);
+		}
+
+		return original;
+	}
+}

src/main/resources/create.mixins.json

@@ -15,6 +15,7 @@
     "LavaSwimmingMixin",
     "MainMixin",
     "MapItemSavedDataMixin",
+    "SmithingMenuMixin",
     "TestCommandMixin",
     "WaterWheelFluidSpreadMixin",
     "accessor.AbstractProjectileDispenseBehaviorAccessor",