March 2026 monthly summary for Buck2 and Buck2-prelude focusing on delivering business value through Kotlin tooling enhancements, build performance improvements, and runtime stability optimizations. The work enabled faster feedback loops, smaller artifacts, and more reliable CI/stability in large-scale builds. Key features delivered: - Kotlin tooling and test discovery improvements: fixed Kotlin test class discovery in Buck2 by updating list_class_names.py to include all top-level Kotlin classes from the JAR, removing the need for the Kotlin test-target workaround. - APK build performance and caching: enabled cache uploads for apk_build, cached KSP2 processor classloaders to avoid repeated class loading, and ensured Kotlin stdlib is not bundled into output JARs (stdlib remains on classpath). - Runtime stability and resource optimization: daemonized health checks and reduced Netty EventLoopGroup threads from 144 to 1 to cut memory usage and startup overhead; health-check thread named for easier debugging. Major bugs fixed: - Kotlin test discovery mismatch resolved for Kotlin sources, ensuring test targets include all relevant Kotlin classes. - Removed unconditional -include-runtime from kotlinc to prevent bundling stdlib into every output JAR, reducing artifact size and I/O without breaking runtime availability. - Health check thread previously prevented JVM shutdown; made the health check executor daemon to ensure clean shutdown of workers. Overall impact and accomplishments: - Build feedback loops accelerated: APK builds become cacheable and faster on cache-hits; observed read-path optimizations decreased APK build times by measurable margins on large artifacts. - Artifact size and I/O reduced: not bundling stdlib into output JARs reduces binary sizes and disk I/O; cacheable artifacts improve CI throughput. - Resource usage and reliability improved: memory usage reduced by up to ~143MB per worker due to fewer Netty threads; safer shutdown behavior with daemon health checks. Technologies and skills demonstrated: - Kotlin tooling, Kotlin compiler flags, and Buck2 build system optimizations. - APK build pipeline optimization, caching strategies, and JAR I/O tuning. - Classloader caching patterns and multi-repo collaboration with Buck2-prelude. - Runtime tuning (Netty, gRPC) and process lifecycle management (daemon threads, observable thread naming).

In April 2025, contributed to facebook/buck2-prelude with two focused efforts to improve class usage reporting and stability: - Key feature: Class Usage Parsing and Merging Performance Refactor. Refactored parsing to remove Jackson dependencies, simplified data structures for class usage reporting, and updated tests. This work aims to reduce build time by optimizing serialization/deserialization (commit e963bef81b4bb96beff4ff8c71bf356c70ee69a5). - Key bug fix: ClassUsageMerger Reliability and Test Corrections. Fixed incorrect package declarations that prevented tests from running and ensured class usage maps merge correctly when one map is empty; tests updated to reflect corrected behavior (commit a3c8563bf4e23040b034082b34a5615c521e3aaf). Overall, these changes improve the reliability and performance of class usage reporting, contributing to faster and more deterministic incremental builds. The work demonstrates strong execution in refactoring, test-driven development, and maintaining compatibility in a core Prelude module.

Monthly summary for 2025-03 focusing on delivering a performance-oriented dependency-tracking refactor and ensuring reliability through test updates. The work delivered aligns with business goals of faster builds, reduced runtime overhead, and easier maintenance for dependency tracking in Buck2-prelude.

October 2024 focused on stabilizing the Kotlin toolchain and cleaning the Litho build to reduce maintenance risk and enable faster iteration. Key features delivered include Kotlin Compiler Dependency Harmonization (consolidating dependencies and migrating toward the standard Kotlin compiler) and Build Cleanup (removal of the shaded litho-compiler-plugin). No major bugs fixed this month; the emphasis was on build reliability, maintainability, and preparing for Kotlin upgrades. Business value: improved build stability and simpler upgrade paths, reducing maintenance overhead and accelerating release readiness. Technologies demonstrated: Kotlin, Gradle/build tooling, dependency management, and artifact hygiene.