tweag/rules_haskell
Feb 2025 – Mar 2026
5 Months active
Languages Used
PythonStarlarkHaskellBashBazel
Technical Skills
Build SystemsEnvironment VariablesHaskellNixBazelCabal
Kyle Butt
PROFILE
Kyle Butt
Kyle contributed to the tweag/rules_haskell repository by engineering robust build system enhancements focused on Haskell and Bazel integration. Over five months, he delivered features such as dynamic linking for binaries and REPL, flexible component-level Cabal configuration, and executable aliasing for vendored packages to improve compatibility and developer productivity. His work addressed evolving requirements in Nix and Bazel environments, including locale handling, path resolution, and documentation control. Using Haskell, Python, and Starlark, Kyle implemented targeted bug fixes and testing infrastructure, ensuring reliable builds and smoother CI workflows. His contributions demonstrated depth in build tool development and cross-environment dependency management.
Overall Statistics
Feature vs Bugs
71%Features
Repository Contributions
15Total
Bugs
2
Commits
15
Features
5
Lines of code
92,592
Activity Months5
Your Network
7 peopleWork History
March 2026
8 Commits • 2 Features
Mar 1, 2026Month: 2026-03 — tweag/rules_haskell Key features delivered: - Disable Haddock documentation generation via attribute: restored ability to disable Haddock generation via an attribute, aligning with Cabal arguments. Commit 30aa75d57c049f4f65046b7aa6acab4057267df3. - Bazel compatibility and build-system robustness: consolidated improvements addressing Bazel 8+ changes, including fixes to stack_snapshot module extension, migration to internal get_cpu_value, robust relative path handling for '..' paths, repository-aware runfiles resolution for Cabal modules, and licensing dependencies updates. Commits include 3bf2d4ebc31eb5e84ff5848be6ac994ed32915ad; dce3edd551e46fd2b19ad4b7f8f311336385fb99; 4b6b62dda6ed10beec7df2262b3637c510b991ad; bbd8a25d8c6e76740656be1e5c1deb089cfd36a8; c3dd18d98b4f1ab66f660c1be8fdc4936357e39e; 581532e11060779e1c9aad0213efb9b7baf5b204; 23347437c91af7e1daa37d07a6e2c5c6f8c1deaf. Major bugs fixed: - Fixed stack_snapshot module extension issues (commit 3bf2d4ebc31eb5e84ff5848be6ac994ed32915ad). - Migrated to internal get_cpu_value to replace deprecated bazel_tools usage (commit dce3edd551e46fd2b19ad4b7f8f311336385fb99). - Corrected package extraction for relative ".." paths in Bazel 8 (commit 4b6b62dda6ed10beec7df2262b3637c510b991ad). - Ensured repo_name is used for runfiles path resolution when building external repos (commit bbd8a25d8c6e76740656be1e5c1deb089cfd36a8). Overall impact and accomplishments: - Significantly improved build reliability and maintainability across Bazel versions, enabling more predictable CI and developer workflows. - Restored explicit control over Haddock docs while aligning with Cabal usage, reducing unnecessary build overhead. - Strengthened cross-repo runfiles handling, licensing consistency, and test coverage, lowering onboarding time for contributors and enabling safer external-repo usage. Technologies/skills demonstrated: - Bazel, rules_haskell, runfiles handling, path resolution for external repos, internal API usage (get_cpu_value), Cabal integration considerations, licensing dependencies (rules_license) and test infrastructure.
8 Commits • 2 Features
Mar 1, 2026Month: 2026-03 — tweag/rules_haskell Key features delivered: - Disable Haddock documentation generation via attribute: restored ability to disable Haddock generation via an attribute, aligning with Cabal arguments. Commit 30aa75d57c049f4f65046b7aa6acab4057267df3. - Bazel compatibility and build-system robustness: consolidated improvements addressing Bazel 8+ changes, including fixes to stack_snapshot module extension, migration to internal get_cpu_value, robust relative path handling for '..' paths, repository-aware runfiles resolution for Cabal modules, and licensing dependencies updates. Commits include 3bf2d4ebc31eb5e84ff5848be6ac994ed32915ad; dce3edd551e46fd2b19ad4b7f8f311336385fb99; 4b6b62dda6ed10beec7df2262b3637c510b991ad; bbd8a25d8c6e76740656be1e5c1deb089cfd36a8; c3dd18d98b4f1ab66f660c1be8fdc4936357e39e; 581532e11060779e1c9aad0213efb9b7baf5b204; 23347437c91af7e1daa37d07a6e2c5c6f8c1deaf. Major bugs fixed: - Fixed stack_snapshot module extension issues (commit 3bf2d4ebc31eb5e84ff5848be6ac994ed32915ad). - Migrated to internal get_cpu_value to replace deprecated bazel_tools usage (commit dce3edd551e46fd2b19ad4b7f8f311336385fb99). - Corrected package extraction for relative ".." paths in Bazel 8 (commit 4b6b62dda6ed10beec7df2262b3637c510b991ad). - Ensured repo_name is used for runfiles path resolution when building external repos (commit bbd8a25d8c6e76740656be1e5c1deb089cfd36a8). Overall impact and accomplishments: - Significantly improved build reliability and maintainability across Bazel versions, enabling more predictable CI and developer workflows. - Restored explicit control over Haddock docs while aligning with Cabal usage, reducing unnecessary build overhead. - Strengthened cross-repo runfiles handling, licensing consistency, and test coverage, lowering onboarding time for contributors and enabling safer external-repo usage. Technologies/skills demonstrated: - Bazel, rules_haskell, runfiles handling, path resolution for external repos, internal API usage (get_cpu_value), Cabal integration considerations, licensing dependencies (rules_license) and test infrastructure.
March 2026
December 2025
3 Commits • 1 Features
Dec 1, 2025December 2025 (2025-12) achieved significant improvements in build flexibility and runtime compatibility for tweag/rules_haskell. Key outcomes include dynamic linking support for Haskell binaries and the REPL to improve compatibility with tools like Haskell Language Server, and a fix to ensure cabal_args correctly apply to library components in stack snapshots. These changes reduce runtime linkage errors, enable easier adoption of dynamic libraries, and align with common developer workflows. Core work was implemented via commits: 320532a9e34b0a6c5c21fb3677925599d5fd6c08, 9b67a52fea91aebf73deccd23686d72a491d4634, and 16e22d2bee32b63409b595ec15319595aab222b4 (bug fix).
December 2025
3 Commits • 1 Features
Dec 1, 2025December 2025 (2025-12) achieved significant improvements in build flexibility and runtime compatibility for tweag/rules_haskell. Key outcomes include dynamic linking support for Haskell binaries and the REPL to improve compatibility with tools like Haskell Language Server, and a fix to ensure cabal_args correctly apply to library components in stack snapshots. These changes reduce runtime linkage errors, enable easier adoption of dynamic libraries, and align with common developer workflows. Core work was implemented via commits: 320532a9e34b0a6c5c21fb3677925599d5fd6c08, 9b67a52fea91aebf73deccd23686d72a491d4634, and 16e22d2bee32b63409b595ec15319595aab222b4 (bug fix).
October 2025
2 Commits • 1 Features
Oct 1, 2025Month 2025-10 — tweag/rules_haskell: Delivered key Cabal build system enhancements with configurable component-level settings and added empty-library testing. Implemented wiring of components_args through the stack_snapshot module facade into the main implementation and introduced testing support for empty Haskell libraries to validate build and integration. No major bugs fixed this month. Impact: enables more flexible, modular Haskell builds, reduces integration risk, and strengthens validation for library/executable compositions. Technologies/skills demonstrated: Cabal, Haskell, stack_snapshot, module facades, testing automation.
2 Commits • 1 Features
Oct 1, 2025Month 2025-10 — tweag/rules_haskell: Delivered key Cabal build system enhancements with configurable component-level settings and added empty-library testing. Implemented wiring of components_args through the stack_snapshot module facade into the main implementation and introduced testing support for empty Haskell libraries to validate build and integration. No major bugs fixed this month. Impact: enables more flexible, modular Haskell builds, reduces integration risk, and strengthens validation for library/executable compositions. Technologies/skills demonstrated: Cabal, Haskell, stack_snapshot, module facades, testing automation.
October 2025
May 2025
1 Commits • 1 Features
May 1, 2025May 2025 monthly summary for tweag/rules_haskell: Delivered a targeted reliability improvement by adding executable aliases for vendored Cabal packages, enabling references from stack snapshots even when Hackage metadata is not updated for new GHC versions. This reduces breakage during GHC upgrades and vendor-tool usage, improving developer productivity and CI stability.
May 2025
1 Commits • 1 Features
May 1, 2025May 2025 monthly summary for tweag/rules_haskell: Delivered a targeted reliability improvement by adding executable aliases for vendored Cabal packages, enabling references from stack snapshots even when Hackage metadata is not updated for new GHC versions. This reduces breakage during GHC upgrades and vendor-tool usage, improving developer productivity and CI stability.
February 2025
1 Commits
Feb 1, 2025February 2025 focused on stabilizing locale handling in Nix-based builds for rules_haskell. Delivered a bug fix that ensures LOCALE_ARCHIVE is correctly propagated to the haskell_cabal_library and haskell_cabal_binary build targets, and canonicalized the LOCALE_ARCHIVE path in cabal_wrapper.py to avoid failures when directories change. This change aligns with the Nixpkgs requirement to have LOCALE_ARCHIVE set, improving locale reliability across environments. The work is captured in commit 6dd476bd1d4e8578583ab92840fba5fa5c1cd345.
1 Commits
Feb 1, 2025February 2025 focused on stabilizing locale handling in Nix-based builds for rules_haskell. Delivered a bug fix that ensures LOCALE_ARCHIVE is correctly propagated to the haskell_cabal_library and haskell_cabal_binary build targets, and canonicalized the LOCALE_ARCHIVE path in cabal_wrapper.py to avoid failures when directories change. This change aligns with the Nixpkgs requirement to have LOCALE_ARCHIVE set, improving locale reliability across environments. The work is captured in commit 6dd476bd1d4e8578583ab92840fba5fa5c1cd345.
February 2025
Activity
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Quality Metrics
Correctness94.8%
Maintainability86.8%
Architecture86.8%
Performance84.0%
AI Usage20.0%
Skills & Technologies
Programming Languages
BashBazelHaskellPythonStarlark
Technical Skills
BazelBuild SystemsBuild Tool DevelopmentCabalContinuous IntegrationDependency ManagementEnvironment VariablesHaskellNixPackage ManagementPythonStatic and Dynamic LinkingTestingbug fixingbuild system configuration
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