Skip invalid Rust toolchains instead of failing by Copilot · Pull Request #1699 · j178/prek

Copilot · 2026-02-27T14:39:00Z

If any rustup toolchain has a broken rustc binary (e.g. a partially-built stage0 sysroot registered via rustup), prek would fail entirely when trying to select a suitable toolchain, even if many valid toolchains were available.

Closes #1695

Changes

rustup.rs: In both list_installed_toolchains() and list_system_toolchains(), replace try_collect() with filter_map() so that toolchains whose rustc --version fails are skipped with a warn! log rather than propagating the error. The overall operation succeeds as long as at least one valid toolchain exists.

// Before: one failure poisons the entire stream
.try_collect()
.await?

// After: bad toolchains are warned and skipped
.filter_map(async move |result| match result {
    Ok(info) => Some(info),
    Err(e) => {
        warn!("Skipping invalid toolchain: {e:#}");
        None
    }
})
.collect()
.await

Original prompt

This section details on the original issue you should resolve

<issue_title>One invalid Rust toolchain causes prek to fail</issue_title>
<issue_description>### Summary

When running a Rust-based hook, I've got the following error:

error: Failed to install hook `oxipng`
  caused by: Failed to install rust
  caused by: Failed to read version from /home/m4tx/projects/rust/build/host/stage0-sysroot/bin/rustc
  caused by: Run command `rustc version` failed
  caused by: No such file or directory (os error 2)

This was very concerning for me at first, since /home/m4tx/projects is a very arbitrary path that I happen to store various repositories in, and I would never expect prek to look for anything in there. Running prek with -vvv did shine some light on this:

2026-02-26T16:45:23.963699Z TRACE Executing `/home/m4tx/.rustup/toolchains/nightly-2025-07-03-x86_64-unknown-linux-gnu/bin/rustc --version`
2026-02-26T16:45:23.963942Z TRACE Executing `/home/m4tx/.rustup/toolchains/1.42.0-x86_64-unknown-linux-gnu/bin/rustc --version`
2026-02-26T16:45:23.964608Z TRACE Executing `/home/m4tx/.rustup/toolchains/1.57.0-x86_64-unknown-linux-gnu/bin/rustc --version`
2026-02-26T16:45:23.964848Z TRACE Executing `/home/m4tx/.rustup/toolchains/1.60-x86_64-unknown-linux-gnu/bin/rustc --version`
2026-02-26T16:45:23.965053Z TRACE Executing `/home/m4tx/.rustup/toolchains/1.64.0-x86_64-unknown-linux-gnu/bin/rustc --version`
2026-02-26T16:45:23.965181Z TRACE Executing `/home/m4tx/.rustup/toolchains/1.70.0-x86_64-unknown-linux-gnu/bin/rustc --version`
2026-02-26T16:45:23.965471Z TRACE Executing `/home/m4tx/.rustup/toolchains/1.75.0-x86_64-unknown-linux-gnu/bin/rustc --version`
2026-02-26T16:45:23.966651Z TRACE Executing `/home/m4tx/.rustup/toolchains/1.77.2-x86_64-unknown-linux-gnu/bin/rustc --version`
2026-02-26T16:45:23.972872Z TRACE Executing `/home/m4tx/.rustup/toolchains/1.78.0-x86_64-unknown-linux-gnu/bin/rustc --version`
2026-02-26T16:45:23.975137Z TRACE Executing `/home/m4tx/.rustup/toolchains/1.79.0-x86_64-unknown-linux-gnu/bin/rustc --version`
2026-02-26T16:45:23.977357Z TRACE Executing `/home/m4tx/.rustup/toolchains/1.80.1-x86_64-unknown-linux-gnu/bin/rustc --version`
2026-02-26T16:45:23.977749Z TRACE Executing `/home/m4tx/.rustup/toolchains/1.81.0-x86_64-unknown-linux-gnu/bin/rustc --version`
2026-02-26T16:45:23.977995Z TRACE Executing `/home/m4tx/.rustup/toolchains/1.84.1-x86_64-unknown-linux-gnu/bin/rustc --version`
2026-02-26T16:45:23.978252Z TRACE Executing `/home/m4tx/.rustup/toolchains/1.85-x86_64-unknown-linux-gnu/bin/rustc --version`
2026-02-26T16:45:23.978423Z TRACE Executing `/home/m4tx/.rustup/toolchains/1.85.1-x86_64-unknown-linux-gnu/bin/rustc --version`
2026-02-26T16:45:23.978681Z TRACE Executing `/home/m4tx/.rustup/toolchains/1.93-x86_64-unknown-linux-gnu/bin/rustc --version`
2026-02-26T16:45:23.983378Z TRACE Executing `/home/m4tx/projects/rust/build/host/stage0-sysroot/bin/rustc --version`

Turns out that I was trying to compile Rust from scratch, which resulted in the toolchain being added to rustup. For the next 6 months ran into any issues because of this (since I had a number of other perfectly working toolchains installed) until I tried prek. Removing the problematic toolchain from rustup has fixed the problem.

I don't think that prek should fail on any when it encounters failure using any toolchain; rather, I would expect it to work if at least one Rust toolchain is usable.

Willing to submit a PR?

Yes — I’m willing to open a PR to fix this.

Platform

Arch Linux, Linux 6.12.74-1-lts x86_64 GNU/Linux

Version

prek 0.3.3

.pre-commit-config.yaml

repos:
  - repo: https://github.com/oxipng/oxipng
    rev: v9.1.4
    hooks:
      - id: oxipng
        args: ["-o", "max", "--strip", "safe", "--alpha"]

Log file

2026-02-26T16:45:23.937725Z DEBUG prek: 0.3.3
2026-02-26T16:45:23.937755Z DEBUG Args: ["prek", "-vvv"]
2026-02-26T16:45:23.938885Z TRACE get_root: close time.busy=1.10ms time.idle=2.87µs
2026-02-26T16:45:23.938914Z DEBUG Git root: /home/m4tx/projects/m4txblog
2026-02-26T16:45:23.938928Z TRACE Executing `/usr/bin/git ls-files --unmerged`
2026-02-26T16:45:23.939978Z DEBUG Found workspace root at `/home/m4tx/projects/m4txblog`
2026-02-26T16:45:23.939988Z TRACE Include selectors: ``
2026-02-26T16:45:23.939993Z TRACE Skip selectors: ``
2026-02-26T16:45:23.940045Z DEBUG discover{root="/home/m4tx/projects/m4txblog" config=None refresh=false}: Loaded workspace from cache
2026-02-26T16:45:23.940061Z DEBUG discover{root="/home/m4tx/projects/m4txblog" config=None refresh=false}: Loading project configuration path=.pre-commit-config.yaml
2026-02-26T16:45:23.940757Z TRACE discover{root="/home/m4tx/projects/m4txblog" config=None refresh=false}: close time.busy=748µs time.idle=1.18µs
2026-02-26T16:45:23.940780Z TRACE Executing `/usr/bin/git diff --exit-code --name-only -z /home/m4tx/projects/m4txblog/.pre-commit-config.yaml`
2026-02-26T1...

</details>



<!-- START COPILOT CODING AGENT SUFFIX -->

- Fixes j178/prek#1695

<!-- START COPILOT CODING AGENT TIPS -->
---

🔒 GitHub Advanced Security automatically protects Copilot coding agent pull requests. You can protect all pull requests by enabling Advanced Security for your repositories. [Learn more about Advanced Security.](https://gh.io/cca-advanced-security)

Co-authored-by: j178 <10510431+j178@users.noreply.github.com>

codecov · 2026-02-27T14:50:35Z

Codecov Report

❌ Patch coverage is 43.75000% with 9 lines in your changes missing coverage. Please review.
✅ Project coverage is 91.55%. Comparing base (a64312f) to head (30a9d81).
⚠️ Report is 1 commits behind head on master.

Files with missing lines	Patch %	Lines
crates/prek/src/languages/rust/rustup.rs	43.75%	9 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #1699      +/-   ##
==========================================
+ Coverage   90.37%   91.55%   +1.18%     
==========================================
  Files          96       96              
  Lines       18880    18892      +12     
==========================================
+ Hits        17062    17296     +234     
+ Misses       1818     1596     -222

☔ View full report in Codecov by Sentry.
📢 Have feedback on the report? Share it here.

🚀 New features to boost your workflow:

❄️ Test Analytics: Detect flaky tests, report on failures, and find test suite problems.

Copilot

Pull request overview

Improves Rust toolchain selection so prek can continue when a rustup-registered toolchain has a broken rustc (e.g., partial stage0 sysroot), instead of failing the entire Rust installer flow.

Changes:

Skip toolchains whose rustc --version fails during toolchain enumeration (instead of erroring out).
Emit a warn! log when a toolchain is skipped.

This MR contains the following updates: | Package | Update | Change | |---|---|---| | [prek](https://github.com/j178/prek) | patch | `0.3.1` → `0.3.13` | MR created with the help of [el-capitano/tools/renovate-bot](https://gitlab.com/el-capitano/tools/renovate-bot). **Proposed changes to behavior should be submitted there as MRs.** --- ### Release Notes <details> <summary>j178/prek (prek)</summary> ### [`v0.3.13`](https://github.com/j178/prek/blob/HEAD/CHANGELOG.md#0313) [Compare Source](j178/prek@v0.3.12...v0.3.13) Released on 2026-05-06. ##### Bug fixes - Respect hook filters for message files ([#2049](j178/prek#2049)) ##### Documentation - Add Godot Engine to users in README ([#2047](j178/prek#2047)) ##### Contributors - [@j178](https://github.com/j178) - [@Calinou](https://github.com/Calinou) ### [`v0.3.12`](https://github.com/j178/prek/blob/HEAD/CHANGELOG.md#0312) [Compare Source](j178/prek@v0.3.11...v0.3.12) Released on 2026-05-05. ##### Highlights `auto_update.cooldown_days` is now available in both the user-level global config (`~/.config/prek/prek.toml` on Linux and macOS, or `$XDG_CONFIG_HOME/prek/prek.toml` when set; `%APPDATA%\prek\prek.toml` on Windows) and project config. Set a user default for `prek auto-update`, then override it per project when a repository needs a different update cadence. ```toml [auto_update] cooldown_days = 7 ``` ##### Enhancements - Add global auto-update cooldown config ([#2041](j178/prek#2041)) - Add project auto-update cooldown config ([#2044](j178/prek#2044)) - Support `language: dart` ([#1146](j178/prek#1146)) ##### Bug fixes - Pass commit message file to workspace hooks ([#2043](j178/prek#2043)) - Preserve non-UTF8 filenames from git ([#2023](j178/prek#2023)) - ruby: put resolved Ruby's bin dir on `$PATH` for `gem` invocations ([#2021](j178/prek#2021)) ##### Documentation - Update docs with the new logo and icon ([#2025](j178/prek#2025)) - Point schema docs to SchemaStore ([#2039](j178/prek#2039)) ##### Contributors - [@j178](https://github.com/j178) - [@xiaoyanli-lyft](https://github.com/xiaoyanli-lyft) - [@Lutra-Fs](https://github.com/Lutra-Fs) ### [`v0.3.11`](https://github.com/j178/prek/blob/HEAD/CHANGELOG.md#0311) [Compare Source](j178/prek@v0.3.10...v0.3.11) Released on 2026-04-27. ##### Highlights Hook entries now have an explicit `shell` option for shell snippets. Set `shell: sh`, `bash`, `pwsh`, `powershell`, or `cmd` when an entry should be evaluated by that shell; leaving it unset keeps prek's direct argv execution. `prek auto-update` can now filter tag candidates before choosing an update. Both options take glob patterns: use `--include-tag` to only consider matching tag names, and `--exclude-tag` to skip matching tags such as moving tags or prereleases. ##### Enhancements - Add `auto-update --exclude-repo <repo>` to skip repos ([#1983](j178/prek#1983)) - Add `auto-update --exit-code` to exit with non-zero on updates ([#2002](j178/prek#2002)) - Add `auto-update --include-tag <pattern>`/`--exclude-tag <pattern>` to filter tags ([#1984](j178/prek#1984)) - Adds an explicit `shell` hook option for entries that should run as shell source ([#2004](j178/prek#2004)) - Make `--hook-dir` optional for hook-impl ([#1989](j178/prek#1989)) - Skip shim warning when `--script-version` is missing ([#1990](j178/prek#1990)) ##### Bug fixes - Install Ruby executable in gem bin ([#2017](j178/prek#2017)) - Use dedicated Android npm package ([#1982](j178/prek#1982)) - Use stable repo keys without breaking cached clones ([#1995](j178/prek#1995)) ##### Documentation - Explain prek name ([#1980](j178/prek#1980)) - Clarify `pass_filenames` concurrency docs ([#1999](j178/prek#1999)) - Reorganize documentation references ([#2005](j178/prek#2005)) - Clarify hook author manifest env docs ([#1991](j178/prek#1991)) - docs: add Sentry to users list ([#1981](j178/prek#1981)) ##### Contributors - [@j178](https://github.com/j178) ### [`v0.3.10`](https://github.com/j178/prek/blob/HEAD/CHANGELOG.md#0310) [Compare Source](j178/prek@v0.3.9...v0.3.10) Released on 2026-04-21. ##### Enhancements - Disallow rev for non-remote repos in schema ([#1964](j178/prek#1964)) - Hide up-to-date output in non-verbose mode ([#1942](j178/prek#1942)) - Improve merge conflict marker detection ([#1937](j178/prek#1937)) - Keep finished hooks visible ([#1967](j178/prek#1967)) - Preserve frozen comment spacing in auto-update ([#1945](j178/prek#1945)) - Reimplement `@j178/prek` npm package ([#1973](j178/prek#1973)) ##### Bug fixes - Prefer stable Rust toolchains ([#1974](j178/prek#1974)) ##### Documentation - Add `SKILL.md` for prek ([#1950](j178/prek#1950)) - Document `gh skill install j178/prek prek` to install prek skill for agents ([#1951](j178/prek#1951)) - Improve compatibility and migration docs ([#1940](j178/prek#1940)) ##### Other changes - Sync latest identify tags ([#1947](j178/prek#1947)) ##### Contributors - [@github-actions](https://github.com/github-actions) - [@renovate](https://github.com/renovate) - [@j178](https://github.com/j178) ### [`v0.3.9`](https://github.com/j178/prek/blob/HEAD/CHANGELOG.md#039) [Compare Source](j178/prek@v0.3.8...v0.3.9) Released on 2026-04-13. ##### Highlight `prek auto-update` is now stricter about pinned revisions and more useful in CI. It now keeps `rev` and `# frozen:` comments in sync, can detect [impostor commits](https://docs.zizmor.sh/audits/#impostor-commit) when validating pinned SHAs, and lets you use `prek auto-update --check` to fail on both available updates and frozen-ref mismatches without rewriting the config. Examples: ```console $ prek auto-update # updates revs and repairs stale `# frozen:` comments $ prek auto-update --freeze # writes frozen SHAs with matching `# frozen: <tag>` comments $ prek auto-update --check # exits non-zero when updates are available, a `# frozen:` comment is stale, # or a pinned SHA does not belong to the fetched upstream refs ``` ##### Enhancements - Check and sync frozen comments during auto-update ([#1896](j178/prek#1896)) - Handle impostor commits in auto-update ([#1919](j178/prek#1919)) - Add experimental `language: dotnet` support ([#1871](j178/prek#1871)) - Honor repo and worktree `core.hooksPath` ([#1892](j178/prek#1892)) - Add `prek run --no-fail-fast` to override config file ([#1859](j178/prek#1859)) - Add `forbid-new-submodules` as builtin hook ([#1853](j178/prek#1853)) - Clean stale patch files in `cache gc` ([#1877](j178/prek#1877)) - Display auto-update results by config entry ([#1922](j178/prek#1922)) - Restrict patch directory permissions ([#1876](j178/prek#1876)) - Show tag names in `auto-update --freeze` output ([#1916](j178/prek#1916)) - Use a bitset for hook stages ([#1860](j178/prek#1860)) ##### Bug fixes - Canonicalize CWD and GIT\_ROOT paths ([#1878](j178/prek#1878)) - Ensure quotes are added for non-string revisions in `auto-update` ([#1936](j178/prek#1936)) ##### Documentation - Update docs for case of hooks modifying files with a non-zero exit code ([#1879](j178/prek#1879)) ##### Contributors - [@RicardoVercetti](https://github.com/RicardoVercetti) - [@nathanjmcdougall](https://github.com/nathanjmcdougall) - [@renovate](https://github.com/renovate) - [@sadjow](https://github.com/sadjow) - [@j178](https://github.com/j178) ### [`v0.3.8`](https://github.com/j178/prek/blob/HEAD/CHANGELOG.md#038) [Compare Source](j178/prek@v0.3.6...v0.3.8) Released on 2026-03-23. ##### Enhancements - Add experimental `language: deno` support ([#1516](j178/prek#1516)) - Add `pretty-format-json` as builtin hook ([#915](j178/prek#915)) - Add `check-vcs-permalinks` as builtin hook ([#1842](j178/prek#1842)) - Add `check-illegal-windows-names` as builtin hook ([#1841](j178/prek#1841)) - Add `check-shebang-scripts-are-executable` builtin hook ([#1847](j178/prek#1847)) - Add `destroyed-symlinks` builtin hook ([#1851](j178/prek#1851)) - Add `file-contents-sorter` as builtin hook ([#1846](j178/prek#1846)) - Add `--all` flag to `prek uninstall` ([#1817](j178/prek#1817)) - Improve file pattern parse errors ([#1829](j178/prek#1829)) - Validate `uv` binary after download ([#1825](j178/prek#1825)) ##### Bug fixes - Fix workspace-relative added file paths ([#1852](j178/prek#1852)) - Relax alias-anchor ratio check for check-yaml ([#1839](j178/prek#1839)) ##### Contributors - [@j178](https://github.com/j178) - [@shaanmajid](https://github.com/shaanmajid) - [@mvanhorn](https://github.com/mvanhorn) - [@feliblo](https://github.com/feliblo) - [@Tiryoh](https://github.com/Tiryoh) ### [`v0.3.6`](https://github.com/j178/prek/blob/HEAD/CHANGELOG.md#036) [Compare Source](j178/prek@v0.3.5...v0.3.6) Released on 2026-03-16. ##### Enhancements - Allow selectors for hook ids containing colons ([#1782](j178/prek#1782)) - Rename `prek install-hooks` to `prek prepare-hooks` and `prek install --install-hooks` to `prek install --prepare-hooks` ([#1766](j178/prek#1766)) - Retry auth-failed repo clones with terminal prompts enabled ([#1761](j178/prek#1761)) ##### Performance - Optimize `detect_private_key` by chunked reading and using aho-corasick ([#1791](j178/prek#1791)) - Optimize `fix_byte_order_marker` by shifting file contents in place ([#1790](j178/prek#1790)) ##### Bug fixes - Align stage defaulting behavior with pre-commit ([#1788](j178/prek#1788)) - Make sure child output is drained in the PTY subprocess ([#1768](j178/prek#1768)) - fix(golang): use `GOTOOLCHAIN=local` when probing system go ([#1797](j178/prek#1797)) ##### Documentation - Disambiguate “hook” terminology by renaming "Git hooks" to "Git shims" ([#1776](j178/prek#1776)) - Document compatibility with pre-commit ([#1767](j178/prek#1767)) - Update configuration.md with TOML 1.1 notes ([#1764](j178/prek#1764)) ##### Other changes - Sync latest identify tags ([#1798](j178/prek#1798)) ##### Contributors - [@github-actions](https://github.com/github-actions) - [@j178](https://github.com/j178) - [@pcastellazzi](https://github.com/pcastellazzi) - [@deadnews](https://github.com/deadnews) - [@copilot-swe-agent](https://github.com/copilot-swe-agent) ### [`v0.3.5`](https://github.com/j178/prek/blob/HEAD/CHANGELOG.md#035) [Compare Source](j178/prek@v0.3.4...v0.3.5) Released on 2026-03-09. ##### Enhancements - Add automatic Ruby download support using rv binaries ([#1668](j178/prek#1668)) - Adjust open file limit on process startup ([#1705](j178/prek#1705)) - Allow parallel gem retry ([#1732](j178/prek#1732)) - Enable system-proxy feature on reqwest ([#1738](j178/prek#1738)) - Expose `--git-dir` to force hook installation target ([#1723](j178/prek#1723)) - Pass `--quiet`, `--verbose`, and `--no-progress` through `prek install` into generated hook scripts ([#1753](j178/prek#1753)) - Respect `core.sharedRepository` for hook permissions ([#1755](j178/prek#1755)) - Support legacy mode hook script ([#1706](j178/prek#1706)) - rust: support `cli:` git dependency 4th segment package disambiguation ([#1747](j178/prek#1747)) ##### Bug fixes - Fix Python `__main__.py` entry ([#1741](j178/prek#1741)) - python: strip `UV_SYSTEM_PYTHON` from `uv venv` and `pip install` commands ([#1756](j178/prek#1756)) ##### Other changes - Sync latest identify tags ([#1733](j178/prek#1733)) ##### Contributors - [@Dev-iL](https://github.com/Dev-iL) - [@tennox](https://github.com/tennox) - [@shaanmajid](https://github.com/shaanmajid) - [@is-alnilam](https://github.com/is-alnilam) - [@github-actions](https://github.com/github-actions) - [@j178](https://github.com/j178) ### [`v0.3.4`](https://github.com/j178/prek/blob/HEAD/CHANGELOG.md#034) [Compare Source](j178/prek@v0.3.3...v0.3.4) Released on 2026-02-28. ##### Enhancements - Allow `pass_filenames` to accept a positive integer ([#1698](j178/prek#1698)) - Install and compile gems in parallel ([#1674](j178/prek#1674)) - Sync identify file-type mappings with pre-commit identify ([#1660](j178/prek#1660)) - Use `--locked` for Rust `cargo install` commands ([#1661](j178/prek#1661)) - Add `PREK_MAX_CONCURRENCY` environment variable for configuring maximum concurrency ([#1697](j178/prek#1697)) - Add `PREK_LOG_TRUNCATE_LIMIT` environment variable for configuring log truncation ([#1679](j178/prek#1679)) - Add support for `python -m prek` ([#1686](j178/prek#1686)) ##### Bug fixes - Skip invalid Rust toolchains instead of failing ([#1699](j178/prek#1699)) ##### Performance - Bitset-based TagSet refactor: precompute tag masks and speed up hook type filtering ([#1665](j178/prek#1665)) ##### Documentation - Document `winget install j178.Prek` ([#1670](j178/prek#1670)) ##### Contributors - [@uplsh580](https://github.com/uplsh580) - [@Svecco](https://github.com/Svecco) - [@dbast](https://github.com/dbast) - [@drichardson](https://github.com/drichardson) - [@JP-Ellis](https://github.com/JP-Ellis) - [@j178](https://github.com/j178) - [@is-alnilam](https://github.com/is-alnilam) - [@copilot-swe-agent](https://github.com/copilot-swe-agent) ### [`v0.3.3`](https://github.com/j178/prek/blob/HEAD/CHANGELOG.md#033) [Compare Source](j178/prek@v0.3.2...v0.3.3) Released on 2026-02-15. ##### Enhancements - Read Python version specifier from hook repo `pyproject.toml` ([#1596](j178/prek#1596)) - Add `#:schema` directives to generated prek.toml ([#1597](j178/prek#1597)) - Add `prek util list-builtins` command ([#1600](j178/prek#1600)) - Expand install source detection to `mise`, `uv tool`, `pipx`, and `asdf` ([#1605](j178/prek#1605), [#1607](j178/prek#1607)) - Add progress bar to `cache clean` and show removal summary ([#1616](j178/prek#1616)) - Make `yaml-to-toml` CONFIG argument optional ([#1593](j178/prek#1593)) - `prek uninstall` removes legacy scripts too ([#1622](j178/prek#1622)) ##### Bug fixes - Fix underflow when formatting summary output ([#1626](j178/prek#1626)) - Match `files/exclude` filter against relative path of nested project ([#1624](j178/prek#1624)) - Select `musllinux` wheel tag for uv on musl-based distros ([#1628](j178/prek#1628)) ##### Documentation - Clarify `prek list` description ([#1604](j178/prek#1604)) ##### Contributors - [@ichoosetoaccept](https://github.com/ichoosetoaccept) - [@shaanmajid](https://github.com/shaanmajid) - [@soraxas](https://github.com/soraxas) - [@9999years](https://github.com/9999years) - [@j178](https://github.com/j178) ### [`v0.3.2`](https://github.com/j178/prek/blob/HEAD/CHANGELOG.md#032) [Compare Source](j178/prek@v0.3.1...v0.3.2) Released on 2026-02-06. ##### Highlights - **`prek.toml` is here!** You can now use `prek.toml` as an alternative to `.pre-commit-config.yaml` for configuring prek. `prek.toml` mirrors the structure of `.pre-commit-config.yaml`, but TOML is less error-prone. Your existing `.pre-commit-config.yaml` will continue to work, but for new users and new projects, `prek.toml` may make more sense. If you want to switch, run `prek util yaml-to-toml` to convert YAML configs to `prek.toml`. See [configuration docs](configuration.md) for details. For example, this config: ```yaml repos: - repo: https://github.com/pre-commit/pre-commit-hooks rev: v6.0.0 hooks: - id: check-yaml ``` Can be written as `prek.toml` like this: ```toml [[repos]] repo = "https://github.com/pre-commit/pre-commit-hooks" rev = "v6.0.0" hooks = [ { id = "check-yaml" } ] ``` - **`serde-yaml` has been replaced with `serde-saphyr`** We replaced the long-deprecated `serde-yaml` crate with [`serde-saphyr`](https://crates.io/crates/serde-saphyr) for YAML parsing. It is written in safe Rust and has better error messages, performance, and security. This lets us provide precise location information for configuration parsing errors, which should make it easier to fix config issues. For example, this invalid config: ```yaml repos: - repo: https://github.com/crate-ci/typos hooks: - id: typos ``` Before: ```console $ prek run error: Failed to parse `.pre-commit-config.yaml` caused by: Invalid remote repo: missing field `rev` ``` Now: ```console $ prek run error: Failed to parse `.pre-commit-config.yaml` caused by: error: line 2 column 5: missing field `rev` at line 2, column 5 --> <input>:2:5 | 1 | repos: 2 | - repo: https://github.com/crate-ci/typos | ^ missing field `rev` at line 2, column 5 3 | hooks: 4 | - id: typos | ``` - **`prek util` subcommands** We added a new `prek util` top-level command for miscellaneous utilities that don't fit into other categories. The first two utilities are: - `prek util identify`: shows the identification tags of files that prek uses for file filtering, which can be useful for debugging and writing `types/types_or/exclude_types` filters. - `prek util yaml-to-toml`: converts `.pre-commit-config.yaml` to `prek.toml`. We also moved `prek init-template-dir` under `prek util` for better organization. The old `prek init-template-dir` command is still available (hidden) as an alias for backward compatibility. ##### Enhancements - Add `prek util identify` subcommand ([#1554](j178/prek#1554)) - Add `prek util yaml-to-toml` to convert `.pre-commit-config.yaml` to `prek.toml` ([#1584](j178/prek#1584)) - Detect install source for actionable upgrade hints ([#1540](j178/prek#1540)) - Detect prek installed by the standalone installer ([#1545](j178/prek#1545)) - Implement `serialize_yaml_scalar` using `serde-saphyr` ([#1534](j178/prek#1534)) - Improve max cli arguments length calculation ([#1518](j178/prek#1518)) - Move `identify` and `init-template-dir` under the `prek util` top-level command ([#1574](j178/prek#1574)) - Replace serde-yaml with serde-saphyr (again) ([#1520](j178/prek#1520)) - Show precise location for config parsing error ([#1530](j178/prek#1530)) - Support `Julia` language ([#1519](j178/prek#1519)) - Support `prek.toml` ([#1271](j178/prek#1271)) - Added `PREK_QUIET` environment variable support ([#1513](j178/prek#1513)) - Remove upper bound constraint of uv version ([#1588](j178/prek#1588)) ##### Bug fixes - Do not make the child a session leader ([#1586](j178/prek#1586)) - Fix FilePattern schema to accept plain strings ([#1564](j178/prek#1564)) - Use semver fallback sort when tag timestamps are equal ([#1579](j178/prek#1579)) ##### Documentation - Add `OpenClaw` to the list of users ([#1517](j178/prek#1517)) - Add `cachix/devenv`, `apache/lucene`, `copper-project/copper-rs` as projects using prek ([#1531](j178/prek#1531), [#1514](j178/prek#1514), [#1569](j178/prek#1569)) - Add document about authoring remote hooks ([#1571](j178/prek#1571)) - Add `llms.txt` generation for LLM-friendly documentation ([#1553](j178/prek#1553)) - Document using `--refresh` to pick up `.prekignore` changes ([#1575](j178/prek#1575)) - Fix PowerShell completion instruction syntax ([#1568](j178/prek#1568)) - Update quick start to use `prek.toml` ([#1576](j178/prek#1576)) ##### Other changes - Include `prek.toml` in run hint for config filename ([#1578](j178/prek#1578)) ##### Contributors - [@fatelei](https://github.com/fatelei) - [@domenkozar](https://github.com/domenkozar) - [@makeecat](https://github.com/makeecat) - [@fllesser](https://github.com/fllesser) - [@j178](https://github.com/j178) - [@copilot-swe-agent](https://github.com/copilot-swe-agent) - [@oopscompiled](https://github.com/oopscompiled) - [@rmuir](https://github.com/rmuir) - [@shaanmajid](https://github.com/shaanmajid) </details> --- ### Configuration 📅 **Schedule**: (UTC) - Branch creation - At any time (no schedule defined) - Automerge - At any time (no schedule defined) 🚦 **Automerge**: Disabled by config. Please merge this manually once you are satisfied. ♻ **Rebasing**: Whenever MR becomes conflicted, or you tick the rebase/retry checkbox. 🔕 **Ignore**: Close this MR and you won't be reminded about this update again. --- - [ ] If you want to rebase/retry this MR, check this box --- This MR has been generated by [Mend Renovate](https://github.com/renovatebot/renovate).

Initial plan

d25b6e5

Copilot AI assigned Copilot and j178 Feb 27, 2026

Copilot started work on behalf of j178 February 27, 2026 14:39 View session

Skip invalid Rust toolchains instead of failing

30a9d81

Co-authored-by: j178 <10510431+j178@users.noreply.github.com>

Copilot AI changed the title ~~[WIP] Fix invalid Rust toolchain causing prek to fail~~ Skip invalid Rust toolchains instead of failing Feb 27, 2026

Copilot finished work on behalf of j178 February 27, 2026 14:47

j178 marked this pull request as ready for review February 27, 2026 14:48

j178 self-requested a review as a code owner February 27, 2026 14:48

Copilot AI review requested due to automatic review settings February 27, 2026 14:48

j178 added the bug Something isn't working label Feb 27, 2026

Copilot started reviewing on behalf of j178 February 27, 2026 14:48 View session

j178 enabled auto-merge (squash) February 27, 2026 14:48

j178 disabled auto-merge February 27, 2026 14:49

j178 approved these changes Feb 27, 2026

View reviewed changes

Copilot AI reviewed Feb 27, 2026

View reviewed changes

Comment thread crates/prek/src/languages/rust/rustup.rs

Comment thread crates/prek/src/languages/rust/rustup.rs

Comment thread crates/prek/src/languages/rust/rustup.rs

j178 merged commit e290094 into master Feb 27, 2026
53 checks passed

j178 deleted the copilot/fix-invalid-rust-toolchain-issue branch February 27, 2026 14:53

BrewTestBot mentioned this pull request Feb 28, 2026

prek 0.3.4 Homebrew/homebrew-core#269872

Merged

Provide feedback

Saved searches

Use saved searches to filter your results more quickly

Uh oh!

Skip invalid Rust toolchains instead of failing#1699

Skip invalid Rust toolchains instead of failing#1699
j178 merged 2 commits into
masterfrom
copilot/fix-invalid-rust-toolchain-issue

Copilot AI commented Feb 27, 2026 •

edited by j178

Loading

Uh oh!

codecov Bot commented Feb 27, 2026 •

edited

Loading

Uh oh!

Copilot AI left a comment

Uh oh!

Uh oh!

Uh oh!

Uh oh!

Uh oh!

Reviewers

Assignees

Labels

Projects

Milestone

Development

Uh oh!

3 participants

Uh oh!

Conversation

Copilot AI commented Feb 27, 2026 • edited by j178 Loading Uh oh! There was an error while loading. Please reload this page.

Uh oh!

Changes

Willing to submit a PR?

Platform

Version

.pre-commit-config.yaml

Log file

Uh oh!

codecov Bot commented Feb 27, 2026 • edited Loading Uh oh! There was an error while loading. Please reload this page.

Uh oh!

Codecov Report

Uh oh!

Copilot AI left a comment

Choose a reason for hiding this comment

Pull request overview

Uh oh!

Uh oh!

Uh oh!

Uh oh!

Uh oh!

Reviewers

Assignees

Labels

Projects

Milestone

Development

Uh oh!

3 participants

Copilot AI commented Feb 27, 2026 •

edited by j178

Loading

codecov Bot commented Feb 27, 2026 •

edited

Loading