Lerna Bootstrap Breaks When Using Yarn Version 2+

Expected Behavior

Lthe Lerna bootstrap command should work with version 2 of Yarn.

Current Behavior

I get the following error when running lerna bootstrap or yarn build with version 2 of Yarn:

Unknown Syntax Error: Unsupported option name ("--mutex").

Possible Solution

Update the @lerna/bootstrap module to use the version 2 Yarn install API.

Steps to Reproduce (for bugs)

In a project set up to work with Yarn version 1 workspaces and Lerna:

1. Follow the Yarn v1 to v2 migration guide
2. run lerna bootstrap
3. Watch it break

lerna.json

<!-- Please paste your `lerna.json` here -->
{
  "useWorkspaces": true,
  "version": "independent",
  "npmClient": "yarn",
  "command": {}
}

Context

Yarn version 1 takes almost an hour to install all our mono repo’s dependencies and bootstrap them. To remedy this we attempted to move to Yarn version 2 (due to its superior caching), which fixed a lot of our issues - but now the lerna bootstrap command stopped working for us.

Your Environment

Executable	Version
lerna --version	4.0.0 (also tested on 3.22.1)
npm --version	7.7.6
yarn --version	2.4.1
node --version	14.15.1

OS	Version
Windows 10	20H2

[MirKml]

As @merceyz mentioned, leave bootstrap up to package managers through workspaces. Use lerna only for automatic change detection, version management and publishing.

Lerna seems unmaintained and this approach can extends lerna usage with up to date tooling, until you prepare replacement.

[khusamov]

$ lerna bootstrap
info cli using local version of lerna
lerna notice cli v4.0.0
lerna info versioning independent
lerna info bootstrap root only
Unknown Syntax Error: Unsupported option name ("--mutex").

$ yarn install [--json] [--immutable] [--immutable-cache] [--check-cache] [--inline-builds] [--mode #0]
lerna ERR! yarn install --mutex network:42424 --non-interactive exited 1 in '******'