Handling versioning in a continuous integration environment - continuous-integration

How do you handle versioning in a continuous integration environment where there is a development branch and a release branch? I'm using git so there is no incrementing repository version to use. Seems like there will be overlapping versions such as 1.1.0 on the dev branch and 1.1.0 on the release branch. Do you just append the text "dev" or "release"?
Also, when you create a release branch do you immediately increment the development branch to the next "proposed" release number? You may not know the next release number yet but if you don't increment it then you have 1.1.0 dev containing new work not included in 1.1.0 release.
So my main question is what is the relationship in the versioning sequences between these two branches?
Keep in mind, I'm not asking anything about how to decide what version numbers to use. I tried asking this before and kept getting comments like "increment major for breaking changes" etc.

I don't version the dev branch. The devline is the trunk and I periodically branch from dev to a new release folder. So the release branch is full of folders which are basically snapshots of the devline.
IE, under root I have /dev, /releases/0.1, /releases/0.2, /releases/1.0, etc.
I'm not sure if this really answers your question.

I would recommend set a final activity for your CI environment to make tags. I believe the git command looks like this: git tag -a name
We use Major.Minor.Release.BuildNumber
though some places use Major.Minor.Release.CheckinNumber
So, if you want to use that then I would version your dev branch, otherwise just version the release branch.

If you have only one development branch, it is more effective to make it be the trunk and branch off a release branch every time you just want to stabilize for release. If you have multiple feature projects, you can have a branch for each of them with CI setup on those. Once they are done, you merge them one by one to the trunk and once all are merged, you get to the first scenario, where you branch a release branch off of the trunk again.
In any case, you don't keep the development branch going between releases. You want to end it and start a new one for development for the next version. This way some of the features can be branched off during several releases if they take longer. But also you don't have too much mess on your development branches.
You can branch the development branches for the next version as soon as you branched the release branch or even before if you chose to, but it is generally good idea once you stabilize for release, merge the changes from release branch into trunk and from there into the development branches if you do that. If you wait with branching off after release, you avoid few merges there, but you slow down development.

Related

mvn jgitflow:release-finish is merging release --> master --> develop

When I was using
mvn jgitflow:release-finish
I noticed that the release branch got merged into master branch.
Question: Is this the correct way?
Sorry my questions might be naive as I am new to this. I was thinking that the code from release branch will merge to develop and master and not like release --> master --> develop.
Question: What if I don't want this to happen and instead I should be in a position to rebase develop from master?
When I was using mvn jgitflow:release-finish I noticed that the release branch got merged into master branch. Is this the correct way?
This is the correct way according to the main philosophy behind, gitflow:
Release branches
May branch off from:develop
Must merge back into: develop and master
And according to the plugin documentation, the release-finish indeed merges back to the master and dev branch:
finishing a release - runs a maven build (deploy or install), merges the release branch, updates pom(s) with development versions
This makes sense, because (again back to gitflow):
When the state of the release branch is ready to become a real release, some actions need to be carried out. First, the release branch is merged into master (since every commit on master is a new release by definition, remember). Next, that commit on master must be tagged for easy future reference to this historical version. Finally, the changes made on the release branch need to be merged back into develop, so that future releases also contain these bug fixes.
I was thinking that the code from release branch will merge to develop and master and not like release --> master --> develop.
The order follows this flow (first master, then develop) because it's a release and as a release it must firstly go to master (which should always represent the released code base), then to develop (whish is the next potential release code base).
What if I don't want this to happen and instead I should be in a position to rebase develop from master.
You can use the noReleaseMerge option:
Whether to turn off merging changes from the release branch to master and develop
Default value is to false, hence by default merges are performed. However, the option covers the two merges, you cannot disable only one of them, it's either both (again, following gitflow philosophy) or none. This option may suit your needs but you would then perform additional actions via git commands.

Make a release from an already released version with CVS

I'm trying to put in place a way to permit to developers to be able to sometimes apply a patch on an already delivered version of an application.
before any delivery to a pre-production env we've to release our app.
code versioning system is CVS
here's the use case :
date 1 : we release the application (with maven) which will be deployed on the server (webapp)
date 2 : on (head) there had been commits
date 3 : a bug appears on the pre-production env and we've to deliver a patch, the problem is that we already committed some unfinished features they must not appear on the pre-production env.
I proposed to checkout the code from the already released version (the one of date 1), make the fix and then release from that version.
My question : Is it possible? what will happen to head?
You can do it as follow :
Suppose that the your tag is 1.0
1 - create a new branch (named for example 1.0-hotfix) from the tag of release (1.0 )
2 - checkout the new branch in another local directory
3 - Make changes to your source, commit and release !
4 - finally merge the branch into HEAD
For maintenance and patches you need to be able to work on parallel versions. Usually this is done with the concept of branches, cvs support this feature.
Maintenance branch are very common to apply patch to older versions.
Nothing will happen to head.
While cvs or svn support branches, the implementation in DVCS such as git is much better. Switching to a DVCS would save you a lot of time in the long run.

Repeated merge of VSS branch->trunk when trunk version unchanged

Merging whole projects is a pain in VSS as the IDE only wants to let you do individual files. I have a situation where we created a new project (in both the VSS and VC++ sense) in a branch, and I then merged/copied this into trunk. All active development is still going on in the branch, the trunk version has no independent changes and this is likely to continue for some time as changes are made in the branch and then merged into trunk.
I wodnered if the easiest solution is simply to delete the trunk version of the project and re-copy the branch version each time, since it avoids the need to do any fiddly stuff and makes sure the trunk version is exactly the same as the branch at time of copying.
Does that seem reasonable or does it introduce problems I hadn't foreseen?
You may also try this: check out the trunk and use Reconcile All in Project Difference dialog box to reconcile the changes in the branch. Here is an article on VSS Project Diff.

Is it possible to use the maven-release-plugin with a specific revision?

I am thinking about a deployment pipeline using SVN, Jenkins and Maven. At the moment I'm stuck at the point where I usually would call mvn release:perform on a working copy.
When thinking in deployment pipelines, I want to create a pipeline where every commit could be used to release a software to test/production. Let's say I have 5 builds, and I decide to release build 3 (with revision 3) to production. There will already be 2 new commits to trunk (which is now at revision 5).
Is it possible to use the maven-release-plugin to checkout/build/tag/commit a release at revision 3? When the maven-release-plugin finishes the release it usually commits the modified POMs to trunk.
I'm happy about any kind of information or advice here, so feel free to point me to books (like http://www.amazon.com/Continuous-Delivery-Deployment-Automation-Addison-Wesley/dp/0321601912), blog posts, Jenkins documentation... Maybe I'm completely on the wrong track.
By default, the release plugin creates the release based on the contents of your working copy, it just ensures that you don't have any uncommitted content before doing so. AFAIK it doesn't force an update of the sources, as that's usually the job of the Continuous Integration system (Jenkins in your case). So whatever is checked out by Jenkins will be released.
What you're trying to do sounds more like a configuration change on the Jenkins side, pointing it to the right revision.
On the other hand, if the POM files are modified as part of the release, but have been changed in SVN in the meantime, you will run into a conflict when Maven wants to check in the modified POM files. That's a situation that might happen, depending on how for back you want to go with the release.
Based on this, it might make more sense to always create a branch before doing a release. So you would create a branch based on revision 3 and then create your release in that branch. This way, you wouldn't run into issues with committing resources that have changed in more recent revisions.
Creating the branch and checking it out could probably be automated through Jenkins and Maven as well.
As far as I tested it, it is not possible.
More explicitely, as nwinler said, when you release, maven try to commit the modified pom. But, if it's an older revision than the current one, SVN will complain that your sources are not up to date. So it won't work. ... as far as I know.
You may read docs about promotion build. I don't find any one clear enough to be pointed out (in th few minutes of the writing of this message).

Multiple feature branches and continuous integration

I've been doing some reading about continuous integration recently and there is a scenario which could occur which I don't understand how to deal with appropriately.
We have a stable mainline/trunk branch and create branches for features. Each developer will keep their own feature branches up to date by merging from trunk into their branch on a regular basis. However it is entirely possible that two or more feature branches could be created and worked on over a period of several weeks or months. In this time many releases of the software could be deployed. This where my confusion arises.
It is very likely that changes for one feature branch will cause merge conflicts with other feature branches. CI suggests you should merge into trunk at least daily which would resolve the conflicts quickly. However, you may not want to merge the feature code into trunk because it may not be finished or you may not want that feature available in the next release. So, how do you deal with this scenario and still follow CI principles of daily code integration?
There are no feature branches in proper CI. Use feature toggles instead.
The idea explained more fully in this article is to merge from the trunk/release branch to feature branches daily, but only merge back in the other direction once a feature meets your definition of 'done'.
Code written by one feature team will be pushed into the trunk once it's complete, and will be 'distributed' to the other teams, where conflicts can be dealt with, as part of the daily merge process.
This doesn't go as far as satisfying Nick's desire for a version control system that can be used a backup tool, unless the changes being made are small enough that they can be committed to the feature branch within a timeframe where the the risk of losing your work is acceptable.
I personally don't try to reintegrate code into the release branch before it's done, and although I've never really tried, I'm sure building feature toggles in for unfinished work has its own issues.
I think they mean merging mainline into the feature branch, not the other way 'round. This way, the feature branch will not deviate from mainline too much, and be kept in an easily mergeable state.
The git folks do the same thing by rebasing feature branches on top of the master branch before submitting a feature.
In my experience with CI, the way that you should keep your feature branches up to date with the main line changes as others have suggested. This has been working me for several releases. If you are using subversion make sure you to merge with the merge history enable. This way when you are trying to merge your changes back to line it will only like you are merging the feature changes to line, not trying resolve conflicts which your feature might have with the main line. If you are using more advance VCS like git the first merge will be a rebase where the second will be a merge.
There are tools that can support you to get thins done more smoothly like this Feature branches with Bamboo
Feature branches committing back into the mainline, and OFTEN is an essential feature of Continuous Integration. For a thorough breakdown, see This Article
There's now some good resources showing how to combine both CI and feature branches. Bamboo or Feature Branch Notifier are some ways to look.
And this is another quite long article showing pros of so called distributed CI. Hereunder, one excerpt explaining the benefits:
Distributed CI has the advantage for Continuous Deployment because it keeps a clean and stable Mainline branch that can always be deployed to Production. During a Centralized CI process, an unstable Mainline will exist if code does not integrate properly (broken build) or if there is unfinished work integrated. This works quite well with iteration release planning, but creates a bottleneck for Continuous Deployment. The direct line from developer branch to Production must be kept clean in CD, Distributed CI does this by only allowing Production ready code to be put into the Mainline.
One thing that still can be challenging is keeping the branch build isolated so that it doesn't pollute your repository of binaries by pushing its branch builds to it. Bamboo seems to address that, but not sure it's as easy with Jenkins.

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