Import one git repo as a subdirectory to another (monorepo maker)

README.md

monorepish

How to use

cd git-monorepo
env PACKAGE_NAME=babel/babel-bridge node import | bash

import.js

const assert = require('assert');

const packageName = process.env.PACKAGE_NAME;
assert(packageName, 'Provide PACKAGE_NAME env variable with name in format: `github-user/github-name`.');
const localName = process.env.LOCAL_NAME || packageName.split('/')[1].replace(/^bem-/, '');

const gitsshUrl = `git@github.com:${packageName}.git`;
const packageSlug = packageName.toLowerCase().replace(/[^a-z0-9]+/g, '-');
const originName = `${packageSlug}--origin`;

const branches = (process.env.BRANCHES || 'master').split(',');

/*
git remote add project-a path/to/project-a
git fetch project-a
git merge --allow-unrelated-histories project-a/master # or whichever branch you want to merge
git remote remove project-a
 */
[
    '\n# Add remote',
    `git remote add ${originName} ${gitsshUrl}`,
    `git fetch -qa ${originName}`,

    // For each branch:
    branches.map(branch => [].concat(
        branch === 'master' // or HEAD?
            ? ([
                '\n# Master branch, clean up the working dir',
                `git checkout -q "${branch}"`,
                `git checkout -q -- .`,
                `git clean -f -d`,
            ])
        // branch !== 'master'
            : (branch = `${localName}/${branch}`,
            [
                `\n# Create a fresh branch "${branch}" with an empty root commit"`,
                `git checkout -q --orphan "${branch}"`,
                `\n# The ignore unmatch is necessary when this was a fresh repo`,
                `git rm -rfq --ignore-unmatch .`,
                `git commit -q --allow-empty -m "Root commit for ${branch} branch"`,
            ]),
        `\n# For branch ${branch}`,
        `git merge -s ours --allow-unrelated-histories --no-commit ${originName}/${branch}`,
        `git read-tree --prefix=packages/${localName}/ -u ${originName}/${branch}`,
        `git commit -q --no-verify --allow-empty -m 'Merging ${localName} to ${branch}'`
    )),

    '\n# Clean up',
    `#git remote remove ${originName}`,
    '\n\n'
].reduce((res, el) => [].concat.apply([], res.concat(el)), [])
    .map(s => console.log(s));