What is JGit Flow and why do I need a Maven plugin?
If you missed my other blog post, I recently released a Java library named jgit-flow that implements the git-flow branching and merging model introduced by Vincent Driessen in Java.
My hope is that developers will use this library to integrate git-flow workflows inside of their Java apps, and to get the ball rolling, I thought I’d be the first integrator.
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In particular, some of the pitfalls of the maven-release-plugin in the context of git-flow are:
- MRP writes .backup and release.properties files to your working tree which are easily committed when they shouldn’t be
- MRP does a build in the prepare goal and a build in the perform goal causing tests to run 2 times
- MRP and git-flow both create tags leaving you with two tags if you forget to delete one of them
- If something goes wrong, MRP usually leaves you in a bad state and rollback doesn’t work most of the time
So I figured the best plan of action was to write a specific plugin to enable git-flow style release workflows, and after a bit of twiddling, I’m pleased to bring you the JGit Flow Maven Plugin.
While the plugin is primarily used to perform releases, it also provides full git-flow functionality including:
- starting a release – creates a release branch and updates pom(s) with release versions
- finishing a release – runs a maven build (deploy or install), merges the release branch, updates pom(s) with development versions
- starting a hotfix – creates a hotfix branch and updates pom(s) with hotfix versions
- finishing a hotfix – runs a maven build (deploy or install), merges the hotfix branch, updates pom(s) with previous versions
- starting a feature – creates a feature branch
- finishing a feature – merges the feature branch
Differences with the Maven Release Plugin
Although the maven-jgitflow-plugin is based on the maven-release-plugin, it does things a bit differently to provide a cleaner workflow…
- doesn’t create any .backup or release.properties files (or any other files in your working tree)
- makes all changes on branches. This means to “roll-back” you can simply delete the branch
- automatically copies any profiles (-P) and user-properties (-D) passed on the command line to the forked maven process when building
- doesn’t run site-deploy
- provides the ability to completely turn off maven deployment
- provides the ability to completely turn off remote pushes/tagging
- Only builds your project once in the finish goal. e.g. if you do release-start and release-finish together, your tests only run once
- Never clones your project to a temp folder
- auto tracks origin based on maven scm values if origin tracking is not already setup (I’m looking at you Bamboo!)
- master branch is always kept at the latest release version (not a SNAPSHOT)
I’m hoping this plugin will help ease the pain of releasing maven projects with git-flow and help reduce the number of groans when someone says “can you do a maven release of…”
If you’re interested in contributing, please fork the Maven JGitFlow Plugin on Bitbucket. When your super cool new feature is ready, just issue a pull request to the develop branch of the main project.
Issue Tracker: https://ecosystem.atlassian.net/projects/MJF
Google Group: https://groups.google.com/forum/#!forum/maven-jgitflow-users
Source Code: https://bitbucket.org/atlassian/jgit-flow
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