8. A Rust binary in PyPI wheels, installed through a setup.py placeholder

Status: accepted (2026-10-13)

Context

check-json5 1.4 was a Python pre-commit hook, pinned by repo: URL and hook id. The rewrite has to install without a Rust toolchain and keep those URLs. Python also cost 13.3 ms a run against 0.7 ms for a Rust binary (one pinned core, 2026-10-13).

Options

• language: rust. Every user needs Rust and waits for a compile.
• A mirror repository with prebuilt binaries. Changes every user's repo: URL.
• maturin wheels with bindings = "bin", pinned by a root setup.py, as typos does.

Decision

Wheels for eight targets behind the placeholder. check-json5 stays on PyPI as an empty shim, with its hook id, command and --strict, through 3.x; 4.0 drops them together.

Consequences

A hook install downloads a binary and compiles nothing. A release sets the version by hand in setup.py and the shim, and the release archives hold the binary from each wheel, so PyPI and GitHub ship the same bytes. The shim costs about 120 lines until 4.0.

Confirmation

The hook CI job installs with pre-commit and prek on three OSes, and the release's versions job checks the versions against the tag.

Revisit if

pre-commit or prek can install a prebuilt binary without Python packaging, or a hook install fails on a platform the wheels cover.