Can Lerna bump prerelease version according to the Conventional Commits specification?

Hi,

Sorry for cross-posting (here and on Stack Overflow) but I just want to understand whether this is a bug or by design.

---

I have two Lerna-managed monorepos (both in independent mode), with three sub-packages each. One repo is in a “production” state (i.e. 1.0.0) the other is in a “prerelease” state (i.e. 1.0.0-alpha.0):

dev (or dev-prerelease)
  |-- packages
  |   |-- major
  |   |   |-- package.json (1.0.0 or 1.0.0-alpha.0)
  |   |-- minor
  |   |   |-- package.json (1.0.0 or 1.0.0-alpha.0)
  |   |-- patch
  |   |   |-- package.json (1.0.0 or 1.0.0-alpha.0)
  |-- package.json
  |-- lerna.json

I then make the following commits in both repositories: (commits follow the Conventional Commits specification)

• A breaking change in the major package
• A new feature in the minor package
• A bug fix in the patch package

And run this command in both repositories:

npx lerna publish --conventional-commits --yes 2>/dev/null

Expected Behavior

In the “production” repo, I can see the following versions

Changes:
 - major: 1.0.0 => 2.0.0 (private)
 - minor: 1.0.0 => 1.1.0 (private)
 - patch: 1.0.0 => 1.0.1 (private)

In the “prerelease” repo, I can see the following versions

Changes:
 - major: 1.0.0-alpha.0 => 2.0.0-alpha.0 (private)
 - minor: 1.0.0-alpha.0 => 1.1.0-alpha.0 (private)
 - patch: 1.0.0-alpha.0 => 1.0.1-alpha.0 (private)

Current Behavior

The “production” repo is updated as expected, however in the “prerelease” repo versions are updated as follow:

Changes:
 - major: 1.0.0-alpha.0 => 1.0.0-alpha.1 (private)
 - minor: 1.0.0-alpha.0 => 1.0.0-alpha.1 (private)
 - patch: 1.0.0-alpha.0 => 1.0.0-alpha.1 (private)

Steps to Reproduce (for bugs)

I made a Minimal Reproducible Example. I have dockerized this; you literally just need to clone the repo and follow the instructions 😉

Your Environment

The Minimal Reproducible Example mentioned above runs in a Docker container:

• Alpine
• Node 12

Executable	Version
lerna --version	3.20.2
npm --version	6.10.0
yarn --version	1.17.3
node --version	12.7.0

[realvorl]

It looks like a feature, I think you are supposed to use the version command to advance the MAJOR, MINOR and PATCH numbers before you prerelease again.

you have to go through the lerna versioning commands

- lerna version major
- lerna version premajor
- lerna version prerelease

now you will see that all the changes made it in your

lerna.json

[phetw]

I found the same issue with one of my monorepo using Lerna 4.0.0. Using

lerna version --conventional-commits --conventional-prerelease

only bump patch. When I tried in newly create repository, using the same command it bumps correctly as per convention. Strange. Did you find the solution ?