Data fixers for turtle owners

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

@@ -9,6 +9,7 @@ import com.mojang.datafixers.DataFixUtils;
 import com.mojang.datafixers.DataFixerBuilder;
 import com.mojang.datafixers.schemas.Schema;
 import dan200.computercraft.shared.datafix.RenamePocketComputerUpgradeFix;
+import dan200.computercraft.shared.datafix.TurtleOwnerFix;
 import dan200.computercraft.shared.datafix.TurtleUpgradeComponentizationFix;
 import net.minecraft.util.datafix.DataFixers;
 import net.minecraft.util.datafix.fixes.ItemStackComponentizationFix;
@@ -63,6 +64,30 @@ abstract class DataFixersMixin {
         return schema;
     }
 
+    /**
+     * Register a {@link TurtleOwnerFix} fix.
+     *
+     * @param schema  The {@code V4424} schema.
+     * @param builder The current datafixer builder.
+     * @return The input schema.
+     */
+    @ModifyArg(
+        method = "addFixers",
+        at = @At(
+            value = "INVOKE",
+            target = "Lnet/minecraft/util/datafix/fixes/FeatureFlagRemoveFix;<init>(Lcom/mojang/datafixers/schemas/Schema;Ljava/lang/String;Ljava/util/Set;)V",
+            ordinal = 4
+        ),
+        index = 0,
+        allow = 1
+    )
+    @SuppressWarnings("UnusedMethod")
+    private static Schema addTurtleOwnerFix(Schema schema, @Local DataFixerBuilder builder) {
+        assertSchemaVersion(schema, DataFixUtils.makeKey(4424, 0));
+        builder.addFixer(new TurtleOwnerFix(schema));
+        return schema;
+    }
+
     @Unique
     private static void assertSchemaVersion(Schema schema, int version) {
         if (schema.getVersionKey() != version) {

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

@@ -0,0 +1,38 @@
+// SPDX-FileCopyrightText: 2025 The CC: Tweaked Developers
+//
+// SPDX-License-Identifier: MPL-2.0
+
+package dan200.computercraft.shared.datafix;
+
+import com.mojang.authlib.GameProfile;
+import com.mojang.datafixers.TypeRewriteRule;
+import com.mojang.datafixers.schemas.Schema;
+import com.mojang.serialization.Dynamic;
+import net.minecraft.util.datafix.fixes.AbstractUUIDFix;
+import net.minecraft.util.datafix.fixes.References;
+
+/**
+ * A {@link com.mojang.datafixers.DataFix} that updates the turtle owner's {@link GameProfile} to use one more
+ * consistent with the rest of the game.
+ */
+public final class TurtleOwnerFix extends AbstractUUIDFix {
+    public TurtleOwnerFix(Schema outputSchema) {
+        super(outputSchema, References.BLOCK_ENTITY);
+    }
+
+    @Override
+    protected TypeRewriteRule makeRule() {
+        return this.fixTypeEverywhereTyped("BlockEntityUUIDFix", getInputSchema().getType(typeReference), typed -> {
+            typed = updateNamedChoice(typed, "computercraft:turtle_normal", TurtleOwnerFix::updateTurtle);
+            return updateNamedChoice(typed, "computercraft:turtle_advanced", TurtleOwnerFix::updateTurtle);
+        });
+    }
+
+    private static Dynamic<?> updateTurtle(Dynamic<?> turtle) {
+        return turtle.update("Owner", profile -> profile
+            .renameField("Name", "name")
+            .remove("LowerId").remove("UpperId")
+            .setFieldIfPresent("id", createUUIDFromLongs(profile, "UpperId", "LowerId"))
+        );
+    }
+}

projects/common/src/main/java/dan200/computercraft/shared/turtle/core/TurtleBrain.java

@@ -5,6 +5,8 @@
 package dan200.computercraft.shared.turtle.core;
 
 import com.mojang.authlib.GameProfile;
+import com.mojang.serialization.Codec;
+import com.mojang.serialization.codecs.RecordCodecBuilder;
 import dan200.computercraft.api.lua.ILuaCallback;
 import dan200.computercraft.api.lua.MethodResult;
 import dan200.computercraft.api.peripheral.IPeripheral;
@@ -26,6 +28,7 @@ import dan200.computercraft.shared.util.Holiday;
 import net.minecraft.core.BlockPos;
 import net.minecraft.core.Direction;
 import net.minecraft.core.Holder;
+import net.minecraft.core.UUIDUtil;
 import net.minecraft.core.component.DataComponentPatch;
 import net.minecraft.core.particles.ParticleTypes;
 import net.minecraft.resources.ResourceLocation;
@@ -62,6 +65,16 @@ public class TurtleBrain implements TurtleAccessInternal {
 
     private static final String NBT_SLOT = "Slot";
 
+    /**
+     * {@link net.minecraft.world.item.component.ResolvableProfile#CODEC}, but resolving to a {@link GameProfile}
+     * directly. We don't use {@link ExtraCodecs#GAME_PROFILE}, as that encodes the UUID as a string, not an int array.
+     */
+    private static final Codec<GameProfile> GAME_PROFILE_CODEC = RecordCodecBuilder.create(instance -> instance.group(
+            UUIDUtil.CODEC.fieldOf("id").forGetter(GameProfile::getId),
+            ExtraCodecs.PLAYER_NAME.fieldOf("name").forGetter(GameProfile::getName)
+        )
+        .apply(instance, GameProfile::new));
+
     private static final int ANIM_DURATION = 8;
 
     private TurtleBlockEntity owner;
@@ -160,7 +173,7 @@ public class TurtleBrain implements TurtleAccessInternal {
         selectedSlot = nbt.getIntOr(NBT_SLOT, 0);
 
         // Read owner
-        owningPlayer = nbt.read("Owner", ExtraCodecs.GAME_PROFILE).orElse(null);
+        owningPlayer = nbt.read("Owner", GAME_PROFILE_CODEC).orElse(null);
     }
 
     public void writeToNBT(ValueOutput nbt) {
@@ -168,8 +181,7 @@ public class TurtleBrain implements TurtleAccessInternal {
 
         // Write state
         nbt.putInt(NBT_SLOT, selectedSlot);
-        nbt.storeNullable("Owner", ExtraCodecs.GAME_PROFILE, owningPlayer);
-        // TODO(1.21.6): Data fixer for this.
+        nbt.storeNullable("Owner", GAME_PROFILE_CODEC, owningPlayer);
     }
 
     public void readDescription(ValueInput nbt) {

projects/common/src/testMod/kotlin/dan200/computercraft/gametest/Turtle_Test.kt

@@ -4,6 +4,7 @@
 
 package dan200.computercraft.gametest
 
+import com.mojang.authlib.GameProfile
 import dan200.computercraft.api.ComputerCraftAPI
 import dan200.computercraft.api.ComputerCraftTags
 import dan200.computercraft.api.detail.ComponentDetailProvider
@@ -26,6 +27,7 @@ import dan200.computercraft.shared.peripheral.monitor.MonitorBlock
 import dan200.computercraft.shared.peripheral.monitor.MonitorEdgeState
 import dan200.computercraft.shared.turtle.apis.TurtleAPI
 import dan200.computercraft.shared.turtle.blocks.TurtleBlockEntity
+import dan200.computercraft.shared.turtle.core.TurtleBrain
 import dan200.computercraft.shared.turtle.core.TurtleCraftCommand
 import dan200.computercraft.shared.turtle.items.TurtleItem
 import dan200.computercraft.shared.util.WaterloggableHelpers
@@ -783,6 +785,9 @@ class Turtle_Test {
             val turtleItem = turtleBe.getItem(0)
             assertEquals(overlay, TurtleItem.getOverlay(turtleItem))
             assertEquals(upgrade, TurtleItem.getUpgrade(turtleItem, TurtleSide.LEFT))
+
+            val owner = (turtleBe.access as TurtleBrain).owningPlayer
+            assertEquals(GameProfile(UUID.fromString("01986ee6-ca3c-3b64-bdcd-02039da5963f"), "Player436"), owner)
         }
     }