Release v0.2.0: Add Testkit module, extended rewrite rules, migration diagnostics, high-performance APIs, and comprehensive documentation updates.

Author: Splatcrafter

CHANGELOG.md

@@ -6,6 +6,65 @@ This project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.htm
 
 ---
 
+## [0.2.0] - 2026-01-06
+
+### Added
+
+#### Testkit Module (`aether-datafixers-testkit`)
+- **TestData** — Fluent builders for creating test data (`TestData.gson().object()...`)
+- **AetherAssertions** — Custom AssertJ assertions for `Dynamic`, `DataResult`, `Typed`
+- **DataFixTester** — Test harness for isolated DataFix testing with fluent API
+- **MigrationTester** — Test harness for full migration chain testing
+- **SchemaTester** — Test harness for schema validation
+- **QuickFix** — Factory methods for common fix patterns (rename, add, remove, transform)
+- **MockSchemas** — Mock schema utilities for testing
+- **RecordingContext** — Context that records warnings for test verification
+
+#### Migration Diagnostics
+- **DiagnosticContext** — Opt-in diagnostic context for capturing migration reports
+- **DiagnosticOptions** — Configurable options (snapshots, rule details, pretty print)
+- **MigrationReport** — Structured report with timing, applied fixes, and touched types
+- **FixExecution** — Per-fix execution details with before/after snapshots
+- **RuleApplication** — Per-rule application details
+
+#### Extended Rewrite Rules
+- `Rules.renameFields(ops, map)` — Batch rename multiple fields
+- `Rules.removeFields(ops, fields...)` — Batch remove multiple fields
+- `Rules.groupFields(ops, target, fields...)` — Group flat fields into nested object
+- `Rules.flattenField(ops, field)` — Flatten nested object to root level
+- `Rules.moveField(ops, source, target)` — Move field between paths
+- `Rules.copyField(ops, source, target)` — Copy field to new location
+- `Rules.transformFieldAt(ops, path, fn)` — Transform at nested path
+- `Rules.renameFieldAt(ops, path, newName)` — Rename at nested path
+- `Rules.removeFieldAt(ops, path)` — Remove at nested path
+- `Rules.addFieldAt(ops, path, value)` — Add at nested path
+- `Rules.ifFieldExists(ops, field, rule)` — Conditional on field existence
+- `Rules.ifFieldMissing(ops, field, rule)` — Conditional on field absence
+- `Rules.ifFieldEquals(ops, field, value, rule)` — Conditional on field value
+
+#### High-Performance APIs
+- **BatchTransform** — Builder for batching multiple field operations
+- `Rules.batch(ops, builder)` — Apply multiple operations in single encode/decode cycle
+- `Rules.conditionalTransform(ops, predicate, transform)` — Single-pass conditional transform
+- `Rules.ifFieldExists(ops, field, transform)` — Single-pass version (Function overload)
+- `Rules.ifFieldMissing(ops, field, transform)` — Single-pass version (Function overload)
+- `Rules.ifFieldEquals(ops, field, value, transform)` — Single-pass version (Function overload)
+
+### Changed
+
+#### Performance Optimizations
+- Path parsing now uses character-based parsing instead of regex with memoization cache
+- `DataFixRegistry.getFixes()` pre-allocates result list and avoids second copy
+- `DataFixerImpl` removes redundant validation in hot path (moved to registration time)
+- Fix version ordering validated once at registration instead of per-application
+
+### Documentation
+- Added comprehensive how-to guides for all extended rules
+- Added migration diagnostics usage guide
+- Updated quick reference with new APIs (including Testkit module)
+
+---
+
 ## [0.1.0] - 2025-12-22
 
 ### 🎉 Initial Release

README.md

@@ -1,6 +1,6 @@
 ![License](https://img.shields.io/badge/license-MIT-red)
 ![Maven Central](https://img.shields.io/maven-central/v/de.splatgames.aether/aether-datafixers)
-![Version](https://img.shields.io/badge/version-0.1.0-orange)
+![Version](https://img.shields.io/badge/version-0.2.0-orange)
 
 # Aether Datafixers 🔧
 
@@ -10,14 +10,17 @@ inspired by Minecraft's DataFixer Upper (DFU), with a focus on **simplicity**, *
 
 ---
 
-## ✨ Features (v0.1.0)
+## ✨ Features (v0.2.0)
 
 - ✅ **Schema-Based Versioning** — Define data types per version with `Schema` and `TypeRegistry`
 - ✅ **Forward Patching** — Apply `DataFix` instances sequentially to migrate data across versions
 - ✅ **Format-Agnostic** — Work with any serialization format via `Dynamic<T>` and `DynamicOps<T>`
 - ✅ **Codec System** — Bidirectional transformation between typed Java objects and dynamic representations
 - ✅ **Type Safety** — Strong typing with `TypeReference` identifiers for data routing
 - ✅ **Testkit** — Fluent test data builders, custom assertions, and test harnesses for DataFix testing
+- ✅ **Migration Diagnostics** — Opt-in structured reports with timing, applied fixes, and snapshots
+- ✅ **Extended Rewrite Rules** — Batch operations, path-based transforms, conditional rules
+- ✅ **High-Performance APIs** — `Rules.batch()` for single-pass multi-operation transforms
 - ✅ **JDK 17+** — Built and tested on modern LTS JVMs
 
 ---
@@ -79,23 +82,23 @@ Dynamic<?> updated = fixer.update(
 <dependency>
     <groupId>de.splatgames.aether</groupId>
     <artifactId>aether-datafixers-core</artifactId>
-    <version>0.1.0</version>
+    <version>0.2.0</version>
 </dependency>
 ```
 
 **Gradle (Groovy)**
 
 ```groovy
 dependencies {
-    implementation 'de.splatgames.aether:aether-datafixers-core:0.1.0'
+    implementation 'de.splatgames.aether:aether-datafixers-core:0.2.0'
 }
 ```
 
 **Gradle (Kotlin)**
 
 ```kotlin
 dependencies {
-    implementation("de.splatgames.aether:aether-datafixers-core:0.1.0")
+    implementation("de.splatgames.aether:aether-datafixers-core:0.2.0")
 }
 ```
 
@@ -115,7 +118,7 @@ The Bill of Materials (BOM) ensures consistent versions across all Aether Datafi
         <dependency>
             <groupId>de.splatgames.aether</groupId>
             <artifactId>aether-datafixers-bom</artifactId>
-            <version>0.1.0</version>
+            <version>0.2.0</version>
             <type>pom</type>
             <scope>import</scope>
         </dependency>
@@ -139,7 +142,7 @@ The Bill of Materials (BOM) ensures consistent versions across all Aether Datafi
 
 ```groovy
 dependencies {
-    implementation platform('de.splatgames.aether:aether-datafixers-bom:0.1.0')
+    implementation platform('de.splatgames.aether:aether-datafixers-bom:0.2.0')
 
     // No version needed
     implementation 'de.splatgames.aether:aether-datafixers-core'
@@ -151,7 +154,7 @@ dependencies {
 
 ```kotlin
 dependencies {
-    implementation(platform("de.splatgames.aether:aether-datafixers-bom:0.1.0"))
+    implementation(platform("de.splatgames.aether:aether-datafixers-bom:0.2.0"))
 
     // No version needed
     implementation("de.splatgames.aether:aether-datafixers-core")
@@ -400,20 +403,21 @@ mvn test
 
 ## 🗺️ Roadmap
 
-- **v0.1.0** (current)
+- **v0.1.0**
   - Core API and default implementations
   - Schema-based versioning with TypeRegistry
   - DataFix forward patching system
   - Dynamic/DynamicOps format abstraction
   - Basic codec infrastructure
 
-- **v0.2.0** (next)
+- **v0.2.0** (current)
   - **Testkit module** — Fluent test data builders, custom AssertJ assertions, test harnesses
-  - **Migration diagnostics** — Optional structured report (applied fixes, touched types, timing)
-  - **Extended rewrite rules** — Common operations like nested rename/move/copy helpers
-  - **Performance optimizations** — Caching, lazy evaluation improvements (doesn't change API or determinism)
+  - **Migration diagnostics** — Opt-in structured reports with timing, applied fixes, and snapshots
+  - **Extended rewrite rules** — Batch operations, path-based transforms, conditional rules
+  - **High-performance APIs** — `Rules.batch()` and single-pass conditional transforms
+  - **Performance optimizations** — Path caching, optimized fix registry, reduced allocations
 
-- **v0.3.0**
+- **v0.3.0** (next)
   - **CLI module** — Migrate files and print/export a migration report (batch-friendly)
   - **Schema tooling** — Runtime schema validation + diff utilities between versions