避免使用maven-release-plugin更新POM版本以进行下一个开发迭代

Question

I'm doing my first release with maven-release-plugin and git. Instead of tagging I'm using the release:branch goal. I'm agree with the complete relase-flow process except in one point: all local dependencies are automatically updated to the next SNAPSHOT version in the development branch.

This is my concrete situation: I'm working in a project with more than 20 maven projects. Let's say all of them are in SNAPSHOT version during development. I want to make a release with the maven plugin. After the release is done, all POM versions have been incremented and set again to SNAPSHOT. If I need to make a change in just one line of code of one project (fix a bug) and I make a new release, all projects (by default) must increment their version again when I've just changed one of them .

In my opinion, it makes more sense to continue the development with the state of the last release (all version without SNAPSHOT). In the next development iteration, I can set manually the next SNAPSHOT version only in these projects that I have changed. In the next release, only the changed projects will be "promoted" to a new version but not all of them.

I think this situation is not exceptional but I didn't found information how to do it (and I don't know if I'm breaking the "release" phylosophy...)

Somedy knows how to avoid update all POMs to the next SNAPSHOT version and leave the POM files as the relase version?

Thank you in advance!

Answer 1

The idea of a multimodule project is that all modules are part of the same release cycle. Even is some modules contain no changes, they will be part of the release. As some may say: versions are cheap. The benefits are bigger compared to the ideal picture you described: it is much easier to manage the versions and to control inter-module dependencies. Keep in mind that both trunk and branches should always have a SNAPSHOT version, since these are the working copies. If you use final versions, releases will fail, since you can't tag the same version twice, neither can you deploy(=upload) the same version twice. This is very important, because Maven relies on the definition that final versions are immutable, ie Maven will never download a final version again once it is available in the local repository.

So if some modules don't have the same release-cycle as the total multimodule project, you should move them out of this multimodule project (or release them all at once).

Answer 2

The differences between releasing individual modules, applications or application systems are summarized in my slideshare presentation http://www.slideshare.net/geertpante/version-mgmt-in-maven (slide 20 and following).

What we sometimes do is set the snapshot version to eg 2.0-SNAPSHOT, and do releases as 1.xy So in development, we always keep using 2.0-SNAPSHOT, but when we release, we choose older versions, eg 1.3, 1.4, and choose 2.0-SNAPSHOT as the next release version.

Also, if you use git, take a look at https://bitbucket.org/atlassian/jgit-flow/wiki/Home . One of the advantages is it keeps a single development branch, and only the releases are merged to the master branch:

mvn jgitflow:release-start -DreleaseVersion=1.2 -DdevelopmentVersion=2.0-SNAPSHOT
mvn jgitflow:release-finish -DreleaseVersion=1.2 -DdevelopmentVersion=2.0-SNAPSHOT