#!/bin/bash

# Borrowing from https://github.com/syncier/pre-commit-hooks-jumanjihouse/blob/master/pre_commit_hooks/protect-first-parent

# Find the correct reference, or fallback to HEAD's abbrev-ref
base="$(
    git rev-parse --abbrev-ref --symbolic-full-name '@{upstream}' 2>/dev/null \
        || git branch -avv | awk '/->/ {print $NF}' 2>/dev/null \
        || :
)"
if [ -z "$base" ]; then base="$(git rev-parse --abbrev-ref HEAD)"; fi

firstParent="$(git show-ref -s "${base}")"

if git rev-list --first-parent "${base}^".. | grep -q "^${firstParent}$"; then
    exit 0
else
    echo Foxtrot detected -- please either rebase or '`git reset --soft`' to recreate your commit.
    exit 1
fi