Singleflight Python health checks with cached interpreter info

[j178]

Add singleflight caching for Python interpreter info to dedupe parallel health checks.

[Copilot]

Pull request overview

This PR adds singleflight caching for Python interpreter information queries to prevent duplicate work when multiple health checks run in parallel. The implementation uses the uv-once-map crate to ensure only one query executes at a time for each Python interpreter path.

Changes:

• Introduced a global cache (PYTHON_INFO_CACHE) using OnceMap to deduplicate concurrent Python info queries
• Created new query_python_info_cached function that wraps the existing query logic with caching
• Updated check_health methods in Python and Pygrep language implementations to use the cached version

Reviewed changes

Copilot reviewed 6 out of 7 changed files in this pull request and generated 2 comments.

Show a summary per file

File	Description
crates/prek/src/languages/python/python.rs	Added caching infrastructure with OnceMap, implemented query_python_info_cached function, and updated check_health to use cached queries
crates/prek/src/languages/python/mod.rs	Updated exports to replace query_python_info with query_python_info_cached
crates/prek/src/languages/pygrep/pygrep.rs	Updated check_health to use query_python_info_cached
crates/prek/Cargo.toml	Added uv-once-map dependency
Cargo.toml	Added uv-once-map version constraint
Cargo.lock	Lock file updates for new dependencies
.pre-commit-config.yaml	Added trailing-whitespace check hook

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[github-actions]

📦 Cargo Bloat Comparison

Binary size change: -0.44% (22.5 MiB → 22.4 MiB)

Expand for cargo-bloat output

Head Branch Results

 File  .text    Size        Crate Name
 0.3%   0.8% 71.5KiB        prek? <prek::cli::Command as clap_builder::derive::Subcommand>::augment_subcommands
 0.2%   0.6% 53.8KiB         prek prek::languages::<impl prek::config::Language>::run::{{closure}}::{{closure}}
 0.2%   0.5% 49.9KiB         prek prek::languages::<impl prek::config::Language>::run::{{closure}}::{{closure}}
 0.2%   0.5% 46.3KiB         prek prek::run::{{closure}}
 0.2%   0.5% 42.7KiB         prek prek::identify::by_extension::{{closure}}
 0.2%   0.5% 42.3KiB         prek prek::cli::run::run::run::{{closure}}
 0.2%   0.4% 35.1KiB         prek prek::languages::<impl prek::config::Language>::install::{{closure}}
 0.1%   0.3% 31.6KiB        prek? <prek::cli::RunArgs as clap_builder::derive::Args>::augment_args
 0.1%   0.3% 29.2KiB  serde_json? <&mut serde_json::de::Deserializer<R> as serde_core::de::Deserializer>::deserialize_struct
 0.1%   0.2% 21.6KiB         prek prek::archive::unzip::{{closure}}
 0.1%   0.2% 21.3KiB clap_builder clap_builder::parser::parser::Parser::get_matches_with
 0.1%   0.2% 21.0KiB         prek prek::hooks::meta_hooks::MetaHooks::run::{{closure}}
 0.1%   0.2% 20.7KiB         prek prek::hooks::meta_hooks::MetaHooks::run::{{closure}}
 0.1%   0.2% 19.6KiB         prek <prek::languages::ruby::ruby::Ruby as prek::languages::LanguageImpl>::install::{{closure}}
 0.1%   0.2% 19.2KiB         prek prek::cli::run::filter::collect_files_from_args::{{closure}}
 0.1%   0.2% 18.9KiB         prek prek::cli::run::filter::collect_files_from_args::{{closure}}
 0.1%   0.2% 18.6KiB         ring ring_core_0_17_14__x25519_ge_frombytes_vartime
 0.1%   0.2% 18.2KiB   hyper_util hyper_util::client::legacy::client::Client<C,B>::send_request::{{closure}}
 0.1%   0.2% 18.1KiB    [Unknown] fe_loose_invert
 0.1%   0.2% 17.7KiB         prek prek::languages::python::uv::InstallSource::install::{{closure}}
36.7%  91.7%  8.2MiB              And 19721 smaller methods. Use -n N to show more.
40.0% 100.0%  9.0MiB              .text section size, the file size is 22.4MiB

Base Branch Results

 File  .text    Size        Crate Name
 0.3%   0.8% 72.4KiB        prek? <prek::cli::Command as clap_builder::derive::Subcommand>::augment_subcommands
 0.2%   0.6% 54.7KiB         prek prek::languages::<impl prek::config::Language>::run::{{closure}}::{{closure}}
 0.2%   0.5% 49.9KiB         prek prek::languages::<impl prek::config::Language>::run::{{closure}}::{{closure}}
 0.2%   0.5% 46.3KiB         prek prek::run::{{closure}}
 0.2%   0.5% 43.0KiB         prek prek::cli::run::run::run::{{closure}}
 0.2%   0.5% 42.7KiB         prek prek::identify::by_extension::{{closure}}
 0.2%   0.4% 35.0KiB         prek prek::languages::<impl prek::config::Language>::install::{{closure}}
 0.1%   0.3% 31.8KiB        prek? <prek::cli::RunArgs as clap_builder::derive::Args>::augment_args
 0.1%   0.3% 30.0KiB  serde_json? <&mut serde_json::de::Deserializer<R> as serde_core::de::Deserializer>::deserialize_struct
 0.1%   0.2% 21.5KiB         prek prek::archive::unzip::{{closure}}
 0.1%   0.2% 21.3KiB clap_builder clap_builder::parser::parser::Parser::get_matches_with
 0.1%   0.2% 20.6KiB         prek prek::hooks::meta_hooks::MetaHooks::run::{{closure}}
 0.1%   0.2% 20.4KiB        prek? <prek::cli::Cli as clap_builder::derive::FromArgMatches>::from_arg_matches_mut
 0.1%   0.2% 19.6KiB         prek <prek::languages::ruby::ruby::Ruby as prek::languages::LanguageImpl>::install::{{closure}}
 0.1%   0.2% 19.2KiB         prek prek::cli::run::filter::collect_files_from_args::{{closure}}
 0.1%   0.2% 18.9KiB         prek prek::cli::run::filter::collect_files_from_args::{{closure}}
 0.1%   0.2% 18.7KiB         prek prek::hooks::meta_hooks::MetaHooks::run::{{closure}}
 0.1%   0.2% 18.6KiB         ring ring_core_0_17_14__x25519_ge_frombytes_vartime
 0.1%   0.2% 18.2KiB   hyper_util hyper_util::client::legacy::client::Client<C,B>::send_request::{{closure}}
 0.1%   0.2% 18.1KiB    [Unknown] fe_loose_invert
36.6%  91.6%  8.2MiB              And 19827 smaller methods. Use -n N to show more.
39.9% 100.0%  9.0MiB              .text section size, the file size is 22.5MiB

[codecov]

Codecov Report

❌ Patch coverage is 72.00000% with 7 lines in your changes missing coverage. Please review.
✅ Project coverage is 90.30%. Comparing base (52c20ab) to head (5d8da4a).
⚠️ Report is 1 commits behind head on master.

Files with missing lines	Patch %	Lines
crates/prek/src/languages/python/python.rs	70.83%	7 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #1381      +/-   ##
==========================================
- Coverage   90.34%   90.30%   -0.04%     
==========================================
  Files          81       81              
  Lines       16122    16143      +21     
==========================================
+ Hits        14565    14578      +13     
- Misses       1557     1565       +8     

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[Copilot]

Pull request overview

Copilot reviewed 5 out of 6 changed files in this pull request and generated no new comments.

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