Crate devx_pre_commit

devx-pre-commit provides utilities for creating git pre-commit hooks.

In particular, there are convenient APIs for

• Efficiently running rustfmt on crates with staged rust source files
• Installing the current binary to .git/hooks/pre-commit

This crate is meant to be used only in dev environment, preferably with cargo-xtask setup. By having something like the code bellow in xtask binary crate you will be able to run the following command to install the git pre-commit hook and never bother running cargo fmt manually again:

cargo xtask install-pre-commit-hook

ℹ️ Note: This assumes there is an alias in .cargo/config:

[alias]
xtask = "run --package xtask --bin xtask --"

Example dev cli:

use devx_pre_commit::{PreCommitContext, locate_project_root};
use anyhow::Result;
use std::{ffi::OsStr, path::PathBuf};

fn run_hook() -> Result<()> {
    let mut ctx = PreCommitContext::from_git_diff(locate_project_root()?)?;

    // Optionally filter out the files you don't want to format
    ctx.retain_staged_files(|path| {
        path.components().all(|it| it.as_os_str() != OsStr::new("generated"))
    });

    // Run `cargo fmt` against the crates with staged rust source files
    ctx.rustfmt()?;

    // Stage all the changes potenitally introduced by rustfmt
    // It is super-important to call this method at the end of the hook
    ctx.stage_new_changes()?;
    Ok(())
}

fn main() -> Result<()> {
    if let Some(true) = std::env::args().next().map(|it| it.contains("pre-commit")) {
        return run_hook();
    }
    match std::env::args().nth(1).expect("No args").as_str() {
        "install-pre-commit-hook" => {
            devx_pre_commit::install_self_as_hook(&locate_project_root()?)?;
        }
        _ => {
            eprintln!("Hi, this is a dev cli, here are the available commands...");
        }
    }
    Ok(())
}

Structs

PreCommitContext

Represents the API entrypoint of the git pre-commit hook. It carries the list of the staged files and the project root path. Note that staged file paths are all relative to the project root path.

Functions

install_self_as_hook	Copies the std::env::current_exe() file to ${project_root}/.git/hooks/pre-commit That’s all you need to register a git pre-commit hook.
locate_project_root	Searches for a project root dir, which is a directory that contains a .git dir as its direct child (it should also be the root of the project’s Rust crate or cargo workspace).