git_hooks/pre-commit for checking gofmt.

pre-commit.zsh

#! /bin/zsh

if command -v gofmt > /dev/null 2>&1; then
    BAD=()
    git diff --cached --name-only --diff-filter=AM | while IFS= read -r f; do 
        if echo "$f" | grep -q '\.go$'; then
            HASH="$(git ls-files --stage -- "$f" | awk '{print $2}')"
            if [ "$(git show "$HASH" | gofmt -l 2>&1)" ]; then
                BAD+=(${f})
            fi
        fi
    done
    if [ ${#BAD} -ne 0 ]; then
        echo The following files have gofmt errors: >&2
        printf '    %s\n' ${BAD[@]} >&2
        exit 1
    fi 
fi