v1.54.0: 17% smaller, up to 31% faster

17% smaller, up to 31% faster

Compared with v1.53.0, the published x86_64-unknown-linux-gnu release is substantially leaner and faster:

Measurement	v1.53.0	v1.54.0	Improvement
Compressed archive	8.19 MB	7.06 MB	13.8% smaller
Extracted binary	22.01 MB	18.27 MB	17.0% smaller
Startup (--version)	2.21 ms	1.52 ms	31.2% faster
Builtins loading	2.31 ms	1.62 ms	29.8% faster
Config validation	3.69 ms	2.94 ms	20.3% faster
Representative check --all	14.62 ms	13.47 ms	7.8% faster

Measurements use the published release binaries with hermetic state, warm caches, shell overhead excluded, and execution pinned to one CPU. Real hook runs dominated by external linters will see a smaller overall percentage.

---

This release adds an opt-in way to focus detailed check diagnostics on only the files that actually failed, teaches hk's usage spec to declare each command's effect on the world, and speeds up the mixed-line-ending and check-merge-conflict builtins along with a new PGO/BOLT-optimized Linux release binary. It also fixes noise and false errors in a couple of builtins.

Added

• Focus checks on failing files (@jdx) #1123. A new opt-in check_failed_files step setting runs a file-listing command (check_list_files or check_diff) over the whole job first, then runs the detailed check only on the paths it reports as failing. This keeps a checker's full diagnostics available without passing every file in a large repository to the second invocation. When enabled, hk requires check plus at least one of check_diff/check_list_files (validated at hk validate time), keeps the listing failure authoritative if the focused check unexpectedly succeeds, and still applies automatic argument-limit batching to the narrowed file set. Addresses discussion #1122.

  ["my-linter"] {
      glob = List("**/*.py")
      check_list_files = "my-linter --list-failing-files {{files}}"
      check = "my-linter check {{files}}"
      fix = "my-linter fix {{files}}"
      check_failed_files = true
  }

• Command effect declarations (@jdx) #1121. Every hk command's usage spec now declares whether it only reads state, modifies it, or is destructive (e.g. uninstall, which removes files from .git/hooks). check, fix, run, and test are deliberately left unclassified because they execute arbitrary steps from hk.pkl — hk cannot promise what those do. Command reference pages now show an Effect line for each command.

Fixed

• tombi-format no longer prints noise on clean runs (@jdx) #1117. tombi format printed a "file did not need formatting" summary to stderr even when nothing changed, which hk surfaced after an otherwise clean run. hk now passes --quiet to both the check and fix commands, suppressing only the summary while still showing the diff and error on failure. Fixes discussion #1116.

• oxlint no longer errors on unmatched patterns (@CallumKerson) #1119. The oxlint builtin now tolerates glob patterns that match no files, matching the behavior already used for the biome builtin.

Performance

• Faster mixed-line-ending and check-merge-conflict (@astei) #1115. Both builtins now use the memchr crate for fast byte scanning instead of iterating byte-by-byte, with the mixed-line-ending fix path doing block copies instead of a per-byte rewrite. Benchmarks show up to ~2.5x faster checks and ~2.2x faster fixes on large files, with neutral-to-positive impact on small ones.

• PGO/BOLT-optimized Linux binary (@jdx) #1136. The x86_64-unknown-linux-gnu release artifact is now built through a profile-guided optimization and BOLT layout pipeline trained on representative Pkl/Git/check workloads. Alongside this, the release binary is stripped and slimmed (narrower Tokio/xx features, panic = "abort"), and the Tokio runtime now caps worker threads at 16.

New Contributors

• @astei made their first contribution in #1115

Full Changelog: v1.53.0...v1.54.0

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