pre-commit

#!/usr/bin/env bash
# Usage: copy this file to .git/hooks/

# Exit at first error
set -Eeu

# To handle partially committed files, we must copy the staged changes to a
# separate location
# See also https://stackoverflow.com/a/36793330
TEMPDIR=$(mktemp -d)
trap 'rm -rf "$TEMPDIR"' EXIT SIGHUP SIGINT SIGQUIT SIGTERM
git checkout-index --prefix="$TEMPDIR/" -af

# keep using the same target/ directory, not a new one in the temporary
# directory this avoids re-parsing everything from scratch every time we run
# the script
GIT_ROOT=$(git rev-parse --show-toplevel)

# lint Rust
if ! git diff --cached --name-only --diff-filter=AM --quiet -- src Cargo.toml Cargo.lock; then
    pushd $TEMPDIR >/dev/null
    export CARGO_TARGET_DIR="${GIT_ROOT}/target"
    echo "Running cargo fmt"
    cargo fmt --check
    echo "Running cargo clippy"
    cargo clippy --all -- --deny warnings
    popd >/dev/null
fi