Add utility to install git hooks.

Adds the `install-git-hooks` to `cross-dev`, which installs pre-commit
hooks to ensure clippy and fmt are run on all commits.

CHANGELOG.md

@@ -63,6 +63,7 @@ This project adheres to [Semantic Versioning](http://semver.org/).
 
 ### Internal
 
+- #787 - add installer for git hooks.
 - #786 - Migrate build script to rust: `cargo build-docker-image $TARGET`
 - #730 - make FreeBSD builds more resilient.
 - #670 - Use serde for deserialization of Cross.toml

xtask/src/install_git_hooks.rs

@@ -0,0 +1,24 @@
+use clap::Args;
+
+use std::path::Path;
+
+#[derive(Args, Debug)]
+pub struct InstallGitHooks {
+    /// Provide verbose diagnostic output.
+    #[clap(short, long)]
+    verbose: bool,
+}
+
+pub fn install_git_hooks(InstallGitHooks { verbose }: InstallGitHooks) -> cross::Result<()> {
+    let metadata = cross::cargo_metadata_with_args(
+        Some(Path::new(env!("CARGO_MANIFEST_DIR"))),
+        None,
+        verbose,
+    )?
+    .ok_or_else(|| eyre::eyre!("could not find cross workspace and its current version"))?;
+    let git_hooks = metadata.workspace_root.join(".git").join("hooks");
+    let cross_dev = metadata.workspace_root.join("xtask").join("src");
+    std::fs::copy(cross_dev.join("pre-commit"), git_hooks.join("pre-commit"))?;
+
+    Ok(())
+}

xtask/src/main.rs

@@ -1,13 +1,15 @@
 #![deny(missing_debug_implementations, rust_2018_idioms)]
 
 pub mod build_docker_image;
+pub mod install_git_hooks;
 pub mod target_info;
 
 use std::path::PathBuf;
 
 use clap::{Parser, Subcommand};
 
 use self::build_docker_image::BuildDockerImage;
+use self::install_git_hooks::InstallGitHooks;
 use self::target_info::TargetInfo;
 
 #[derive(Parser, Debug)]
@@ -22,6 +24,7 @@ enum Commands {
     /// Extract and print info for targets.
     TargetInfo(TargetInfo),
     BuildDockerImage(BuildDockerImage),
+    InstallGitHooks(InstallGitHooks),
 }
 
 pub fn main() -> cross::Result<()> {
@@ -36,6 +39,9 @@ pub fn main() -> cross::Result<()> {
             let engine = get_container_engine(args.engine.as_deref())?;
             build_docker_image::build_docker_image(args, &engine)?;
         }
+        Commands::InstallGitHooks(args) => {
+            install_git_hooks::install_git_hooks(args)?;
+        }
     }
 
     Ok(())

xtask/src/pre-commit

@@ -0,0 +1,11 @@
+#!/bin/env bash
+
+echo "Running rustfmt and clippy checks."
+
+set -ex
+
+cargo fmt -- --check
+cargo clippy --all-features -- --deny warnings
+if cargo +nightly >/dev/null 2>&1; then
+    cargo +nightly clippy --all-features -- --deny warnings
+fi