Extend builder and codec support for up to 8 fields

aether-datafixers-api/src/main/java/de/splatgames/aether/datafixers/api/codec/Codecs.java

@@ -31,7 +31,6 @@
 
 import java.util.ArrayList;
 import java.util.List;
-import java.util.Objects;
 import java.util.Optional;
 
 /**
@@ -766,8 +765,8 @@ public <T> DataResult<T> encode(@NotNull final Pair<F, S> input,
                 Preconditions.checkNotNull(input, "input must not be null");
                 Preconditions.checkNotNull(ops, "ops must not be null");
                 Preconditions.checkNotNull(prefix, "prefix must not be null");
-                return first.encode(Objects.requireNonNull(input.first()), ops, prefix)
-                        .flatMap(t -> second.encode(Objects.requireNonNull(input.second()), ops, t));
+                return first.encode(Preconditions.checkNotNull(input.first(), "pair first must not be null"), ops, prefix)
+                        .flatMap(t -> second.encode(Preconditions.checkNotNull(input.second(), "pair second must not be null"), ops, t));
             }
 
             @NotNull
@@ -777,13 +776,13 @@ public <T> DataResult<Pair<Pair<F, S>, T>> decode(@NotNull final DynamicOps<T> o
                 Preconditions.checkNotNull(ops, "ops must not be null");
                 Preconditions.checkNotNull(input, "input must not be null");
                 return first.decode(ops, input).flatMap(p1 ->
-                        second.decode(ops, Objects.requireNonNull(p1.second())).map(p2 ->
+                        second.decode(ops, Preconditions.checkNotNull(p1.second(), "first decode remainder must not be null")).map(p2 ->
                                 Pair.of(
                                         Pair.of(
-                                                Objects.requireNonNull(p1.first()),
-                                                Objects.requireNonNull(p2.first())
+                                                Preconditions.checkNotNull(p1.first(), "first decode value must not be null"),
+                                                Preconditions.checkNotNull(p2.first(), "second decode value must not be null")
                                         ),
-                                        Objects.requireNonNull(p2.second())
+                                        Preconditions.checkNotNull(p2.second(), "second decode remainder must not be null")
                                 )
                         )
                 );

aether-datafixers-api/src/main/java/de/splatgames/aether/datafixers/api/diagnostic/FixExecution.java

@@ -59,8 +59,10 @@
  * @param startTime        the instant when the fix started
  * @param duration         the total time taken to apply the fix
  * @param ruleApplications list of individual rule applications within this fix
- * @param beforeSnapshot   optional snapshot of data before the fix was applied
- * @param afterSnapshot    optional snapshot of data after the fix was applied
+ * @param beforeSnapshot   snapshot of data before the fix was applied, or {@code null}
+ *                         if snapshot capture was disabled in {@link DiagnosticOptions}
+ * @param afterSnapshot    snapshot of data after the fix was applied, or {@code null}
+ *                         if snapshot capture was disabled or the fix failed
  * @author Erik Pförtner
  * @see RuleApplication
  * @see MigrationReport

aether-datafixers-api/src/main/java/de/splatgames/aether/datafixers/api/exception/DataFixerException.java

@@ -25,6 +25,8 @@
 import org.jetbrains.annotations.NotNull;
 import org.jetbrains.annotations.Nullable;
 
+import java.io.Serial;
+
 /**
  * Base exception class for all data fixer related errors.
  *
@@ -74,6 +76,15 @@
  */
 public class DataFixerException extends RuntimeException {
 
+    /**
+     * Serial version UID for serialization compatibility.
+     */
+    @Serial
+    private static final long serialVersionUID = 2074356976574888083L;
+
+    /**
+     * Optional context information about where the error occurred (e.g., field path, type name).
+     */
     @Nullable
     private final String context;
 
@@ -145,9 +156,10 @@ public String getContext() {
      */
     @Override
     public String toString() {
+        final String base = getClass().getSimpleName() + ": " + getMessage();
         if (this.context != null) {
-            return super.toString() + " [context: " + this.context + "]";
+            return base + " [context: " + this.context + "]";
         }
-        return super.toString();
+        return base;
     }
 }

aether-datafixers-api/src/main/java/de/splatgames/aether/datafixers/api/util/Unit.java

@@ -24,6 +24,9 @@
 
 import org.jetbrains.annotations.NotNull;
 
+import java.io.Serial;
+import java.io.Serializable;
+
 /**
  * A singleton type representing the absence of a meaningful value.
  *
@@ -65,7 +68,7 @@
  * @see de.splatgames.aether.datafixers.api.result.DataResult
  * @since 0.1.0
  */
-public final class Unit {
+public final class Unit implements Serializable {
 
     /**
      * The singleton instance of Unit.
@@ -76,6 +79,15 @@ public final class Unit {
     @NotNull
     public static final Unit INSTANCE = new Unit();
 
+    /**
+     * Serial version UID for serialization compatibility.
+     *
+     * <p>This value is arbitrary but should be changed if the class structure changes in a way that affects
+     * serialization.</p>
+     */
+    @Serial
+    private static final long serialVersionUID = -7628105959309438762L;
+
     /**
      * Private constructor to prevent external instantiation.
      *
@@ -120,4 +132,14 @@ public int hashCode() {
     public boolean equals(final Object obj) {
         return obj instanceof Unit;
     }
+
+    /**
+     * Preserves the singleton guarantee during deserialization.
+     *
+     * @return {@link #INSTANCE}
+     */
+    @Serial
+    private Object readResolve() {
+        return INSTANCE;
+    }
 }

aether-datafixers-testkit/src/main/java/de/splatgames/aether/datafixers/testkit/TestDataBuilder.java

@@ -37,7 +37,9 @@
  * A fluent builder for creating {@link Dynamic} objects.
  *
  * <p>This builder provides a clean, readable API for constructing test data
- * without the boilerplate of manual JSON construction. It supports primitives,
+ * without the boilerplate of manual JSON construction. Each builder instance should
+ * only be used for a single {@link #build()} call — create a new instance for each
+ * Dynamic value. It supports primitives,
  * nested objects, and lists through method chaining.</p>
  *
  * <h2>Basic Usage</h2>

aether-datafixers-testkit/src/main/java/de/splatgames/aether/datafixers/testkit/TestDataListBuilder.java

@@ -320,6 +320,22 @@ public TestDataListBuilder<T> addAll(final double... values) {
         return this;
     }
 
+    /**
+     * Adds multiple float elements to the list.
+     *
+     * @param values the float values
+     * @return this builder for chaining
+     * @throws NullPointerException if {@code values} is null
+     */
+    @NotNull
+    public TestDataListBuilder<T> addAll(final float... values) {
+        Preconditions.checkNotNull(values, "values must not be null");
+        for (final float value : values) {
+            this.add(value);
+        }
+        return this;
+    }
+
     /**
      * Adds multiple boolean elements to the list.
      *