@lerna/import

Import a package into the monorepo with commit history

Install lerna for access to the lerna CLI.

Usage

$ lerna import <path-to-external-repository>

Import the package at <path-to-external-repository>, with commit history, into packages/<directory-name>. Original commit authors, dates and messages are preserved. Commits are applied to the current branch.

This is useful for gathering pre-existing standalone packages into a Lerna repo. Each commit is modified to make changes relative to the package directory. So, for example, the commit that added package.json will instead add packages/<directory-name>/package.json.

Note: If you're importing an external repository on a new lerna repository, then do remember to have at least one commit.

# Getting started with Lerna
$ git init lerna-repo && cd lerna-repo
$ npx lerna init
$ npm install

# Adding a commit
$ git add .
$ git commit -m "Initial lerna commit" # Without a commit, import command would fail

# Importing other repository
$ npx lerna import <path-to-external-repository>

Options

--flatten

When importing repositories with merge commits with conflicts, the import command will fail trying to apply all commits. The user can use this flag to ask for import of "flat" history, i.e. with each merge commit as a single change the merge introduced.

$ lerna import ~/Product --flatten

--dest

When importing repositories, you can specify the destination directory by the directory listed in lerna.json.

$ lerna import ~/Product --dest=utilities

--preserve-commit

Each git commit has an author and a committer (with a separate date for each). Usually they're the same person (and date), but since lerna import re-creates each commit from the external repository, the committer becomes the current git user (and date). This is technically correct, but may be undesireable, for example, on Github, which displays both the author and committer if they're different people, leading to potentially confusing history/blames on imported commits.

Enabling this option preserves the original committer (and commit date) to avoid such issues.

$ lerna import ~/Product --preserve-commit