[BUG] Inc function give incorrect version when bumping subsequent pre versions

[fjcasternao]

Is there an existing issue for this?

• I have searched the existing issues

Current Behavior

We have found that trying to increment any preversion (premajor, preminor, prepatch) results in wrong version calculation

Expected Behavior

The expected behavior will be the prerelease number to bump on subsequent prereleases

Steps To Reproduce

You can check any of the following test, all failing in increment.js
['1.2.0-dev.2', 'preminor', '1.2.0-dev.3', false, 'dev', false],
['2.0.0-dev.2', 'premajor', '2.0.0-dev.3', false, 'dev', false],
['1.2.1-dev.2', 'prepatch', '1.2.1-dev.3', false, 'dev', false],

Environment

No response

[fjcasternao]

I am trying to address this issue in #643

[wraithgar]

Increasing 1.2.0-dev.2 by preminor means bumping a minor and then down to a prerelease of that minor version. So the result that semver gives of 1.3.0-0 is correct. If you need a prerelease identifier you can specify that:

~/D/n/n/b/main (main|✔) $ node -e "console.log(require('.').inc('1.2.0-dev.2', 'preminor'))"
1.3.0-0
~/D/n/n/b/main (main|✔) $ node -e "console.log(require('.').inc('1.2.0-dev.2', 'preminor', 'alpha'))"
1.3.0-alpha.0

The difference between 1.2.0-dev.2 and 1.2.0-dev.3 is only a prerelease

~/D/n/n/b/main (main|✔) $ node -e "console.log(require('.').inc('1.2.0-dev.2', 'prerelease'))"
1.2.0-dev.3

Ref: https://github.com/npm/node-semver#functions

[fjcasternao]

Thanks a lot for your response. Just as a summary before closing this and the associated PR, If I am bumping versions like in the flow you describe, the operations would be:

1.4.3 -> preminor -> 1.5.0-0 -> prerelease -> 1.5.0-1 -> prerelease -> 1.5.0-2 -> minor -> 1.5.0

[wraithgar]

Yep that looks right.