Improve the base map error messages

Author: ErrorCraft

src/main/java/net/errorcraft/codecium/mixin/mojang/serialization/codecs/BaseMapCodecExtender.java

@@ -0,0 +1,73 @@
+package net.errorcraft.codecium.mixin.mojang.serialization.codecs;
+
+import com.llamalad7.mixinextras.injector.wrapoperation.Operation;
+import com.llamalad7.mixinextras.injector.wrapoperation.WrapOperation;
+import com.llamalad7.mixinextras.sugar.Local;
+import com.mojang.datafixers.util.Pair;
+import com.mojang.serialization.Codec;
+import com.mojang.serialization.DataResult;
+import com.mojang.serialization.DynamicOps;
+import com.mojang.serialization.codecs.BaseMapCodec;
+import net.errorcraft.codecium.util.StringUtil;
+import org.spongepowered.asm.mixin.Mixin;
+import org.spongepowered.asm.mixin.Shadow;
+import org.spongepowered.asm.mixin.injection.At;
+import org.spongepowered.asm.mixin.injection.ModifyArg;
+
+import java.util.Optional;
+import java.util.function.Supplier;
+import java.util.function.UnaryOperator;
+
+@Mixin(value = BaseMapCodec.class, remap = false)
+public interface BaseMapCodecExtender<K, V> {
+    @Shadow
+    Codec<K> keyCodec();
+
+    @ModifyArg(
+        method = "lambda$decode$3",
+        at = @At(
+            value = "INVOKE",
+            target = "Lcom/mojang/serialization/DataResult;error(Ljava/util/function/Supplier;)Lcom/mojang/serialization/DataResult;"
+        )
+    )
+    @SuppressWarnings({ "OptionalUsedAsFieldOrParameterType", "OptionalGetWithoutIsPresent" })
+    private <T> Supplier<String> duplicateFieldUseBetterErrorMessage(Supplier<String> message, @Local(argsOnly = true) final DynamicOps<T> ops, @Local(argsOnly = true) final Pair<T, T> pair, @Local final Optional<Pair<K, V>> entry) {
+        return () -> "Duplicate field " + this.keyCodec().encodeStart(ops, entry.get().getFirst()).getOrThrow() + ": " + pair.getFirst();
+    }
+
+    @WrapOperation(
+        method = "lambda$decode$3",
+        at = @At(
+            value = "INVOKE",
+            target = "Lcom/mojang/serialization/Codec;parse(Lcom/mojang/serialization/DynamicOps;Ljava/lang/Object;)Lcom/mojang/serialization/DataResult;",
+            ordinal = 0
+        )
+    )
+    private <T> DataResult<K> addKeyToKeyErrorMessage(Codec<K> instance, final DynamicOps<T> dynamicOps, Object o, Operation<DataResult<K>> original, @Local(argsOnly = true) final Pair<T, T> pair) {
+        return original.call(instance, dynamicOps, o)
+            .mapError(message -> "For key " + pair.getFirst() + ": " + message);
+    }
+
+    @ModifyArg(
+        method = "lambda$decode$3",
+        at = @At(
+            value = "INVOKE",
+            target = "Lcom/mojang/serialization/DataResult;apply2stable(Ljava/util/function/BiFunction;Lcom/mojang/serialization/DataResult;)Lcom/mojang/serialization/DataResult;",
+            ordinal = 0
+        )
+    )
+    private <T> DataResult<V> addKeyToValueErrorMessage(DataResult<V> second, @Local(argsOnly = true) final Pair<T, T> pair) {
+        return second.mapError(message -> "For value " + pair.getFirst() + ": " + message);
+    }
+
+    @ModifyArg(
+        method = "decode",
+        at = @At(
+            value = "INVOKE",
+            target = "Lcom/mojang/serialization/DataResult;mapError(Ljava/util/function/UnaryOperator;)Lcom/mojang/serialization/DataResult;"
+        )
+    )
+    private <T> UnaryOperator<String> mapErrorsUseBetterErrorMessage(UnaryOperator<String> function, @Local final T errors) {
+        return message -> "Map has errors:\n" + StringUtil.indent(message);
+    }
+}

src/main/resources/codecium.mixins.json

@@ -13,6 +13,7 @@
     "mojang.serialization.JsonOpsExtender",
     "mojang.serialization.JsonOpsExtender$MapLikeExtender",
     "mojang.serialization.MapLikeExtender$ForMapExtender",
+    "mojang.serialization.codecs.BaseMapCodecExtender",
     "mojang.serialization.codecs.EitherCodecExtender",
     "mojang.serialization.codecs.FieldDecoderExtender",
     "mojang.serialization.codecs.OptionalFieldCodecExtender",