Move block entity component fixes to separate fixer

Some mods run their own datafixer chain, rather than piggybacking on top
of vanilla's. This is A BAD IDEA, but what can you do. If such a mod
tries to use ItemStackComponentizationFix in their own schema, then
CC:T's mixins will try to look up the turtle block entitie, and fail (as
they're not registered under the modded schema).

We now inject the block entity fix as a separate fixer, rather than
abusing ItemStackComponentizationFix.

See #2012

projects/common/src/main/java/dan200/computercraft/mixin/DataFixersMixin.java

@@ -0,0 +1,51 @@
+// SPDX-FileCopyrightText: 2024 The CC: Tweaked Developers
+//
+// SPDX-License-Identifier: MPL-2.0
+
+package dan200.computercraft.mixin;
+
+import com.llamalad7.mixinextras.sugar.Local;
+import com.mojang.datafixers.DataFixUtils;
+import com.mojang.datafixers.DataFixerBuilder;
+import com.mojang.datafixers.schemas.Schema;
+import dan200.computercraft.shared.datafix.TurtleUpgradeComponentizationFix;
+import net.minecraft.util.datafix.DataFixers;
+import net.minecraft.util.datafix.fixes.ItemStackComponentizationFix;
+import net.minecraft.util.datafix.schemas.V3818_5;
+import org.spongepowered.asm.mixin.Mixin;
+import org.spongepowered.asm.mixin.Unique;
+import org.spongepowered.asm.mixin.injection.At;
+import org.spongepowered.asm.mixin.injection.ModifyArg;
+
+@Mixin(DataFixers.class)
+abstract class DataFixersMixin {
+    /**
+     * Register {@link TurtleUpgradeComponentizationFix} alongside {@link ItemStackComponentizationFix}.
+     * <p>
+     * We use a {@link ModifyArg} to capture the schema passed to {@link ItemStackComponentizationFix}. This is a
+     * little gross, but is the easiest way to obtain the schema without hard-coding local ordinals.
+     *
+     * @param schema  The {@link V3818_5} schema.
+     * @param builder The current datafixer builder
+     * @return The input schema.
+     */
+    @ModifyArg(
+        method = "addFixers",
+        at = @At(value = "INVOKE", target = "Lnet/minecraft/util/datafix/fixes/ItemStackComponentizationFix;<init>(Lcom/mojang/datafixers/schemas/Schema;)V"),
+        index = 0,
+        allow = 1
+    )
+    @SuppressWarnings("UnusedMethod")
+    private static Schema addComponentizationFixes(Schema schema, @Local DataFixerBuilder builder) {
+        assertSchemaVersion(schema, DataFixUtils.makeKey(3818, 5));
+        builder.addFixer(new TurtleUpgradeComponentizationFix(schema));
+        return schema;
+    }
+
+    @Unique
+    private static void assertSchemaVersion(Schema schema, int version) {
+        if (schema.getVersionKey() != version) {
+            throw new IllegalStateException("Unexpected schema version. Expected " + version + ", got " + schema.getVersionKey());
+        }
+    }
+}

projects/common/src/main/java/dan200/computercraft/mixin/ItemStackComponentizationFixMixin.java

@@ -4,14 +4,11 @@
 
 package dan200.computercraft.mixin;
 
-import com.llamalad7.mixinextras.injector.ModifyReturnValue;
 import com.mojang.datafixers.DataFix;
-import com.mojang.datafixers.TypeRewriteRule;
 import com.mojang.datafixers.schemas.Schema;
 import com.mojang.serialization.Dynamic;
-import dan200.computercraft.shared.util.ComponentizationFixers;
+import dan200.computercraft.shared.datafix.ComponentizationFixers;
 import net.minecraft.util.datafix.fixes.ItemStackComponentizationFix;
-import net.minecraft.util.datafix.fixes.References;
 import org.spongepowered.asm.mixin.Mixin;
 import org.spongepowered.asm.mixin.injection.At;
 import org.spongepowered.asm.mixin.injection.Inject;
@@ -35,15 +32,4 @@ abstract class ItemStackComponentizationFixMixin extends DataFix {
     private static void fixItemStack(ItemStackComponentizationFix.ItemStackData data, Dynamic<?> ops, CallbackInfo ci) {
         ComponentizationFixers.fixItemComponents(data, ops);
     }
-
-    @ModifyReturnValue(method = "makeRule", at = @At("RETURN"), remap = false)
-    @SuppressWarnings("UnusedMethod")
-    private TypeRewriteRule wrapMakeRule(TypeRewriteRule existing) {
-        return TypeRewriteRule.seq(existing, fixTypeEverywhereTyped(
-            "Turtle upgrade componentization",
-            getInputSchema().getType(References.BLOCK_ENTITY),
-            getOutputSchema().getType(References.BLOCK_ENTITY),
-            ComponentizationFixers.makeBlockEntityRewrites(getInputSchema(), getOutputSchema())
-        ));
-    }
 }

projects/common/src/main/java/dan200/computercraft/shared/datafix/ComponentizationFixers.java

@@ -2,7 +2,7 @@
 //
 // SPDX-License-Identifier: MPL-2.0
 
-package dan200.computercraft.shared.util;
+package dan200.computercraft.shared.datafix;
 
 import com.mojang.datafixers.DSL;
 import com.mojang.datafixers.Typed;

projects/common/src/main/java/dan200/computercraft/shared/datafix/TurtleUpgradeComponentizationFix.java

@@ -0,0 +1,31 @@
+// SPDX-FileCopyrightText: 2024 The CC: Tweaked Developers
+//
+// SPDX-License-Identifier: MPL-2.0
+
+package dan200.computercraft.shared.datafix;
+
+import com.mojang.datafixers.DataFix;
+import com.mojang.datafixers.TypeRewriteRule;
+import com.mojang.datafixers.schemas.Schema;
+import net.minecraft.util.datafix.fixes.References;
+
+/**
+ * Rewrites turtle block entities to store upgrades as components.
+ *
+ * @see ComponentizationFixers#makeBlockEntityRewrites(Schema, Schema)
+ */
+public class TurtleUpgradeComponentizationFix extends DataFix {
+    public TurtleUpgradeComponentizationFix(Schema outputSchema) {
+        super(outputSchema, true);
+    }
+
+    @Override
+    protected TypeRewriteRule makeRule() {
+        return fixTypeEverywhereTyped(
+            "Turtle upgrade componentization",
+            getInputSchema().getType(References.BLOCK_ENTITY),
+            getOutputSchema().getType(References.BLOCK_ENTITY),
+            ComponentizationFixers.makeBlockEntityRewrites(getInputSchema(), getOutputSchema())
+        );
+    }
+}

projects/common/src/main/resources/computercraft.mixins.json

@@ -7,6 +7,7 @@
         "defaultRequire": 1
     },
     "mixins": [
+        "DataFixersMixin",
         "ItemStackComponentizationFixMixin",
         "V1460Mixin"
     ]

projects/fabric/src/main/java/dan200/computercraft/mixin/V3818_3Mixin.java

@@ -7,7 +7,7 @@ package dan200.computercraft.mixin;
 import com.llamalad7.mixinextras.injector.ModifyReturnValue;
 import com.mojang.datafixers.schemas.Schema;
 import com.mojang.datafixers.types.templates.TypeTemplate;
-import dan200.computercraft.shared.util.ComponentizationFixers;
+import dan200.computercraft.shared.datafix.ComponentizationFixers;
 import net.minecraft.util.datafix.schemas.V3818_3;
 import org.spongepowered.asm.mixin.Mixin;
 import org.spongepowered.asm.mixin.injection.At;

projects/forge/src/main/java/dan200/computercraft/mixin/V3818_3Mixin.java

@@ -7,7 +7,7 @@ package dan200.computercraft.mixin;
 import com.llamalad7.mixinextras.injector.ModifyReturnValue;
 import com.mojang.datafixers.schemas.Schema;
 import com.mojang.datafixers.types.templates.TypeTemplate;
-import dan200.computercraft.shared.util.ComponentizationFixers;
+import dan200.computercraft.shared.datafix.ComponentizationFixers;
 import net.minecraft.util.datafix.schemas.V3818_3;
 import org.spongepowered.asm.mixin.Mixin;
 import org.spongepowered.asm.mixin.injection.At;