April 2026 — chipsalliance/chisel: Delivered deprecation of the Convert phase in the Chisel framework with explicit in-code deprecation messaging and migration guidance to ElaboratedCircuit. No major bugs fixed for this repository in April 2026. Impact: streamline API surface, reduce user confusion during migration, and advance the framework modernization roadmap. Commit reference: 6f8377101d24589fc55f7a93fde93c521fb8b2c1 (Deprecate Convert phase).

March 2026 monthly summary for chipsalliance/chisel: Delivered important build and module-connection enhancements focusing on Scala 3.8.2 compatibility and improved InstanceChoice handling. These changes expand language compatibility, streamline developer workflow, and strengthen module composition for future features.

February 2026 monthly summary focused on stabilizing and expanding Mill-based build tooling and cross-JVM compatibility. Key features delivered include CI and build compatibility updates for Java 11/17 publishing across Scala versions (2.13.x and Scala 3.x) with removal of Java 11-specific logic to broaden compatibility; Mill upgraded to incorporate system property propagation fixes and Unidoc alignment to improve docs/test output, followed by a rollback to a stable Mill 1.0.6 due to native client property issues; Mill formatting crash fix addressed formatting crashes and improved readability of .mill files. In com-lihaoyi/mill, added GraalVM Native Image option -H:-ParseRuntimeOptions to prevent runtime options from being consumed by Scalatest, improving argument propagation and build reliability. Top 3-5 achievements for the month: - Implemented cross-JVM publishing CI for Java 11/17 across Scala 2.13.x and Scala 3.x, removing legacy Java 11 logic to broaden compatibility. - Fixed Mill formatting crash and performed code reformatting to improve readability of .mill files. - Upgraded Mill to 1.1.1-6 with system property propagation to ScalaTest and Unidoc alignment; subsequently rolled back to Mill 1.0.6 with JVM client to address native client property issues. - Added GraalVM Native Image option -H:-ParseRuntimeOptions to prevent runtime options from being consumed, improving argument propagation to Scalatest and build reliability. - Overall impact: more robust build pipelines, improved developer experience, and reliable cross-JVM publishing enabling faster releases.

January 2026 monthly summary focusing on delivering Scala 3 readiness, robust CI, and scalable hardware generation in Chisel, plus cross-cutting Linux compatibility improvements in Mill. Highlights include Scala 3 source-info tooling, publishing readiness, module flattening with dedup, CI/test infrastructure overhaul, and ScalaDoc publishing support, delivering measurable business value through faster adoption, safer releases, and improved developer productivity.

December 2025 (2025-12) monthly summary for chipsalliance/chisel: Focused on security hardening, CI reliability, and developer experience improvements. Delivered several cross-version build enhancements and domain/view handling improvements, along with release automation to streamline artifact publishing. The work spans dependency updates, codebase cleanup, and targeted feature work across Chisel and Scala tooling, with a clear emphasis on business value and technical robustness.

November 2025 monthly summary for chipsalliance/chisel: focused on modernizing the build toolchain and ensuring accurate compatibility guidance. Upgraded Mill to 1.0.6-jvm and Scala to 2.13.18 to improve build reliability, compatibility, and enable downstream bug fixes and performance improvements; updated the Java/Scala compatibility documentation to reflect the latest supported versions, reducing user installation issues and support overhead.

October 2025 (2025-10) – Delivered a set of foundational compatibility, serialization, and documentation improvements in the chipsalliance/chisel repository, focused on enabling future Scala 3 readiness and reducing noise in generated output. This release aligns the codebase with Scala 2.13.17, introduces a flexible JSON serialization override mechanism, and adds a controllable suppressSourceInfo workflow in FIRRTL output. Documentation was updated to reflect the latest compatibility notes for Java/Scala. These changes improve maintainability, collaboration, and long-term scalability while preserving behavioral correctness.

September 2025 monthly summary for chipsalliance/chisel focusing on stability, release readiness, and data accuracy. Key outcomes include API modernization with improved compatibility, documentation and version data accuracy improvements, and fixes that strengthen module initialization correctness. The month culminated in preparing the Chisel 7.1.0 release surface and restoring formal binary compatibility checks, enabling safer upgrades for downstream users.

Summary for 2025-08: In August, CHISEL delivered four major features with a strong emphasis on build tooling stabilization, test coverage, and FIRRTL compatibility, delivering business value through reproducible builds, robust testing, and forward compatibility with the FIRRTL spec. Key features delivered: - Mill Build Tool Version Management: Bumped Mill to 1.0.2 and 1.0.3, removed the standalone version file, and embedded the version in build.mill to ensure single-source truth and easier maintenance. - PopCount Test Coverage Enhancement: Expanded test coverage to all widths 1 through 7 with unique tests, removing redundant width selections to improve regression detection and test clarity. - Chisel Cat Operation Enhancements: Enhanced the Cat operation to support variadic arguments and mixed signed/unsigned integers; introduced PrimExpr in IR and added tests for single-expression cats and stress cases to improve correctness and edge-case handling. - FIRRTL Version Upgrade: Upgraded emitted FIRRTL version from 5.1.0 to 6.0.0 across core and firrtl modules and tests to maintain compatibility with the new specification. Major bugs fixed: - No explicit major bug fixes documented for the month; the primary focus was feature delivery and tooling stabilization, which reduces risk and enhances maintainability. Overall impact and accomplishments: - Improved release readiness and reproducibility through consolidated build tooling and single-source versioning. - Strengthened correctness and coverage in core features (PopCount, Cat) and IR representation (PrimExpr). - Achieved forward compatibility with FIRRTL 6.0.0, aligning with upcoming specs and downstream tooling. - Enhanced test robustness and reliability, enabling faster iteration and confidence for downstream users. Technologies/skills demonstrated: - Mill build system version management and build.mill integration - Scala/Chisel/FIRRTL ecosystem expertise - Variadic operations and mixed signed/unsigned handling in Cat - IR enhancements (PrimExpr) and comprehensive test design - Build/test automation, release engineering, and compatibility upgrades

July 2025: Key release automation, build modernization, and API/documentation improvements for chipsalliance/chisel. Delivered a streamlined release workflow with CI that publishes releases only on tag pushes, enabled direct Maven Central publishing, and introduced an upstream SNAPSHOT publishing flow via a new script. Upgraded Mill to the 1.0.x series, migrating build configurations from Ivy to Maven, adopting moduleDir, with a follow-up 1.0.1 that removes a test path workaround. Maintained dependencies and configuration (os-lib 0.10.7, mdoc 2.7.1; Scala CLI config updates for repository URL and directive formats). Enhanced API documentation by adding ScalaDoc for Bits, relocating ScalaDoc definitions, and introducing sumWidthInt for API completeness.

June 2025 monthly summary for chipsalliance/chisel focusing on delivering business value through debugging and serialization improvements, coupled with build stability enhancements.

Month: 2025-05 — Delivered a focused set of user-facing and developer-oriented improvements for chipsalliance/chisel, enhancing community engagement, navigation, and ecosystem consistency, while strengthening runtime robustness. Highlights include a refreshed community page for accurate repo visibility, a published Latch Up 2025 recap with a dedicated talk tag, broadened unapply support across all namable types in the Naming plugin, and a robust fix to connection error handling for null parent names to prevent crashes. These efforts reduce user friction, improve content and developer tooling, and lower operational risk in edge cases.

April 2025 highlights for chipsalliance/chisel: delivered substantial improvements across printing, simulation logging, runtime inlining, dynamic indexing, and release automation, while cleaning up legacy FIRRTL APIs and stabilizing tests. Key commits demonstrate a leaning toward clearer APIs, faster runtime behavior, and more reliable CI. - Printing API enhancements: printf formatting supports width/padding modifiers and a new %T specifier; older Printable.unpack APIs deprecated in favor of a unified API. Commits include 66448a62, 136294df, e69a27b1. - Runtime inlining of module instances: introduced inlineInstance and inlineInstanceAllowDedup with new annotations and tests to optimize runtime composition. Commit: 5d955e30. - SimLog API and enhanced simulation logging: add SimLog for file-based logging, support runtime-varying filenames via Printable, improved error checks, and a flush capability. Commits: 46ac74ba, b4dac39b, 43bba602. - DynamicIndexBinding for Vec dynamic indices: improved error handling and messaging when using dynamic indices, ensuring correct dontTouch behavior. Commit: 4a953b38. - CI publishing and release process improvements: refactored publish logic, added Scala 3 labeling in release notes, and improved Bits-related ScalaDoc grouping. Commits: 74d717d4, 19887fe9, d4acb2ef. - FIRRTL API cleanup (cleanup groundwork): deprecate the firrtl package in preparation for removal. Commit: 990d37a8. Overall, these efforts enhance developer productivity, reduce CI flakiness, and align Chisel/FIRRTL APIs with upcoming Scala 3 releases and future roadmap.

March 2025 focused on stability, compatibility, and developer productivity for the Chipsalliance/chisel project. Key features delivered include Scala 2.13.16 cross-compilation to align with downstream toolchains (#4691) and a new Serializer for ChiselIR (#4748). The codebase also advanced API encapsulation with a broad switch of core types (Data, Clock, Disable, Aggregate, Bits, BitPat, Mux, Num, Mem, and ChiselEnum) from veneer to private macro interfaces, enabling safer refactoring and clearer API boundaries across core components. Additional improvements included enabling inlining in Scalac options (#4813) and supporting printing hierarchical Verilog names (%m) (#4820). A consistent maintenance and tooling posture was maintained to ensure reproducible builds and explicit action provenance (#4798-#4799).

February 2025 monthly summary for chipsalliance/chisel: Delivered API modernization and robustness improvements in the Chisel core, migrated documentation tooling to Mill, refined Panama publishing workflows, and enhanced website support for Scala CLI examples. These efforts reduced technical debt, improved build reliability, and accelerated the delivery of safe circuit representations and up-to-date documentation and examples.

January 2025 (2025-01) monthly summary for chipsalliance/chisel. Focused on delivering core features that improve reliability, diagnostics, and developer experience, while tightening build tooling and documentation to stabilize delivery and publishing across Scala versions. This period delivered concrete value in error visibility, robustness of utilities after module instantiation, Verilog compatibility knowledge, and tooling modernization.

December 2024 monthly summary for chipsalliance/chisel focusing on delivering high-value features, stabilizing test validation, and enhancing code quality across the repository. Emphasizes business impact through improved naming consistency, stronger test coverage, and robust property handling.

November 2024 summary for chipsalliance/chisel: Focused on API ergonomics, module system flexibility, and release engineering to improve cross-version stability and time-to-market. No major customer-facing bugs reported this month; stability improvements were achieved through targeted refactors and CI/CD enhancements. Delivered three core feature streams that add long-term business value and set the stage for broader adoption. Key outcomes include: (1) API surface enhancements for Lookupable with Unit type support and new factory methods, (2) a more flexible Module Prefixing System with local prefixing, clearer naming, and an option to omit the prefix separator, and (3) release-process hardening via restored scalacOptions across Scala versions, updated scala-reflect compatibility, and CI/CD improvements including parallel test execution and increased release artifact handling.