Summary for 2026-04 (cachix/devenv): Focused on reliability and distributed messaging enhancements. Delivered a dynamic RabbitMQ port management feature to prevent port collisions across environments by allocating RABBITMQ_DIST_PORT and ERL_EPMD_PORT, enabling robust distributed messaging. Hardened the FileWatcher by filtering and draining queued events and preventing unnecessary restarts, with tests to validate reliability.

Monthly summary for 2026-03 (cachix/devenv) focusing on delivering faster, more reliable dev environments and expanding infra capabilities. Key features delivered and improvements: - Evaluation caching improvements and stability: sped up repeated evaluations and improved correctness by enhancing the evaluation cache and introducing an observer pattern for inputs, reducing unnecessary re-evaluation during devenv up. See commits: 79bcd4c3cdd488eb5c5c8a1c957d2e1a43ce3f52; 7483216e99a3ba4dee5670231a8877ea037e1d32; 045c6dd4ad2a30acffbafebd7405c38a925cd432. - Stale shell eval cache fix: resolved stale shell eval cache entries that caused devenv shell and direnv activation to ignore devenv.nix changes, improving consistency of the active environment. Commit: 8923b5c4b4aece8cf8ed8694813055e362ea7df7. - Mosquitto MQTT broker integration and documentation: added Mosquitto support via a new Nix module, testing environment, and updated docs (including removal of deprecated option), expanding infra capabilities. Commits: a0eaf4bab36b2b34d24fc63b65a5671b782dce62; 0340c0189e16a9edd82786e771bfcbf88a1f2577; e7c1f7d56053ce4812252568d32511b9547d3664; 7a820a7ef452e116490c2952d6cea63409bb5825; 7055971c09d51176f92ede120e0cd527403f894b. Major bugs fixed: - Fixed stale shell eval cache causing outdated devenv.nix configurations to impact shell and direnv activation. This aligns the shell environment with config changes and reduces surprising env drift. (8923b5c4) - Corrected cache invalidation behavior so that config changes invalidate the shell cache, preventing stale environments from being reused across devenv info/print-dev-env/shell/direnv operations. (7483216e99a3baa...) Overall impact and accomplishments: - Faster, more reliable dev environments through improved evaluation cache reuse and robust invalidation logic, reducing developer wait time and cognitive overhead. - Consistent dev shell environments that reflect latest configuration, lowering the risk of subtle environment drift. - Expanded infra capabilities with Mosquitto MQTT broker support, enabling new integration patterns and testing scenarios, accompanied by updated documentation. Technologies and skills demonstrated: - Nix module development, Rust-based ffi/eval cache management, and direnv integration. - Cache invalidation strategies, observer pattern design for input tracking, and versioning tied to CLI-provided nix_args. - Testing and documentation for new services (Mosquitto) and configuration changes.