Remove git env vars from uv pip install subprocess

[shaanmajid]

Summary

• Remove GIT environment variables before running uv pip install to prevent setuptools_scm file discovery failures
• Add regression test that fails without the fix and passes with the fix

Problem

When prek runs inside a git worktree, git sets GIT_DIR pointing to the worktree's gitdir. This leaks into uv pip install, causing packages using setuptools_scm for file discovery to have their git ls-files query the wrong repository.

This results in missing package data files (e.g., validate-pyproject's schema JSON files).

Fixes #1354

Test Plan

• mise run lint passes
• Verified fix using worktree MRE from issue — validate-pyproject hook now installs correctly with all 239 files in SOURCES.txt (was 44)
• Added regression test git_env_vars_not_leaked_to_pip_install — verified it fails without the fix and passes with the fix

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 90.11%. Comparing base (2e1ffa3) to head (f4a756e).
⚠️ Report is 5 commits behind head on master.

Additional details and impacted files

@@           Coverage Diff           @@
##           master    #1355   +/-   ##
=======================================
  Coverage   90.11%   90.11%           
=======================================
  Files          80       80           
  Lines       15924    15927    +3     
=======================================
+ Hits        14350    14353    +3     
  Misses       1574     1574           

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[github-actions]

📦 Cargo Bloat Comparison

Binary size change: +0.00% (16.7 MiB → 16.7 MiB)

Expand for cargo-bloat output

Head Branch Results

 File  .text     Size          Crate Name
 0.7%   1.5% 119.5KiB           prek prek::languages::<impl prek::config::Language>::run::{{closure}}::{{closure}}
 0.6%   1.3% 107.3KiB          prek? <prek::cli::Command as clap_builder::derive::Subcommand>::augment_subcommands
 0.3%   0.7%  54.7KiB           prek prek::archive::unpack::{{closure}}
 0.3%   0.7%  52.8KiB             h2 h2::proto::connection::Connection<T,P,B>::poll
 0.2%   0.5%  39.8KiB           prek prek::languages::<impl prek::config::Language>::install::{{closure}}
 0.2%   0.5%  39.2KiB          prek? <prek::cli::RunArgs as clap_builder::derive::Args>::augment_args
 0.2%   0.5%  39.2KiB           prek prek::run::{{closure}}
 0.2%   0.5%  37.3KiB          hyper hyper::proto::h1::dispatch::Dispatcher<D,Bs,I,T>::poll_loop
 0.2%   0.5%  36.9KiB regex_automata regex_automata::meta::strategy::new
 0.2%   0.5%  36.5KiB           prek prek::workspace::Workspace::discover
 0.2%   0.4%  30.8KiB           std? <core::marker::PhantomData<T> as serde_core::de::DeserializeSeed>::deserialize
 0.2%   0.4%  30.8KiB           prek prek::cli::run::run::run::{{closure}}
 0.2%   0.4%  29.8KiB           prek prek::languages::rust::installer::RustInstaller::install::{{closure}}
 0.2%   0.4%  28.4KiB           prek prek::languages::node::installer::NodeInstaller::install::{{closure}}
 0.2%   0.4%  28.4KiB             h2 h2::proto::connection::DynConnection<B>::recv_frame
 0.2%   0.3%  27.6KiB           prek prek::identify::by_extension::{{closure}}
 0.2%   0.3%  27.3KiB           prek prek::cli::run::run::run_hooks::{{closure}}
 0.2%   0.3%  26.2KiB           prek prek::cli::auto_update::update_repo::{{closure}}
 0.1%   0.3%  24.9KiB     hyper_util hyper_util::client::legacy::client::Client<C,B>::connect_to::{{closure}}::{{closure}}::{{closure}}
 0.1%   0.3%  24.7KiB           prek prek::hook::HookBuilder::build::{{closure}}
41.3%  88.4%   6.9MiB                And 10645 smaller methods. Use -n N to show more.
46.7% 100.0%   7.8MiB                .text section size, the file size is 16.7MiB

Base Branch Results

 File  .text     Size          Crate Name
 0.7%   1.5% 119.5KiB           prek prek::languages::<impl prek::config::Language>::run::{{closure}}::{{closure}}
 0.6%   1.3% 107.3KiB          prek? <prek::cli::Command as clap_builder::derive::Subcommand>::augment_subcommands
 0.3%   0.7%  54.7KiB           prek prek::archive::unpack::{{closure}}
 0.3%   0.7%  52.8KiB             h2 h2::proto::connection::Connection<T,P,B>::poll
 0.2%   0.5%  39.8KiB           prek prek::languages::<impl prek::config::Language>::install::{{closure}}
 0.2%   0.5%  39.2KiB          prek? <prek::cli::RunArgs as clap_builder::derive::Args>::augment_args
 0.2%   0.5%  39.2KiB           prek prek::run::{{closure}}
 0.2%   0.5%  37.3KiB          hyper hyper::proto::h1::dispatch::Dispatcher<D,Bs,I,T>::poll_loop
 0.2%   0.5%  36.9KiB regex_automata regex_automata::meta::strategy::new
 0.2%   0.5%  36.5KiB           prek prek::workspace::Workspace::discover
 0.2%   0.4%  30.8KiB           std? <core::marker::PhantomData<T> as serde_core::de::DeserializeSeed>::deserialize
 0.2%   0.4%  30.8KiB           prek prek::cli::run::run::run::{{closure}}
 0.2%   0.4%  29.8KiB           prek prek::languages::rust::installer::RustInstaller::install::{{closure}}
 0.2%   0.4%  28.4KiB           prek prek::languages::node::installer::NodeInstaller::install::{{closure}}
 0.2%   0.4%  28.4KiB             h2 h2::proto::connection::DynConnection<B>::recv_frame
 0.2%   0.3%  27.6KiB           prek prek::identify::by_extension::{{closure}}
 0.2%   0.3%  27.3KiB           prek prek::cli::run::run::run_hooks::{{closure}}
 0.2%   0.3%  26.2KiB           prek prek::cli::auto_update::update_repo::{{closure}}
 0.1%   0.3%  24.9KiB     hyper_util hyper_util::client::legacy::client::Client<C,B>::connect_to::{{closure}}::{{closure}}::{{closure}}
 0.1%   0.3%  24.7KiB           prek prek::hook::HookBuilder::build::{{closure}}
41.3%  88.4%   6.9MiB                And 10645 smaller methods. Use -n N to show more.
46.7% 100.0%   7.8MiB                .text section size, the file size is 16.7MiB

[j178]

Thanks!