Hopefully you have already read my post from last week, Subversion merge made easy.  In that post, I linked to information on the new CollabNet Merge client that we are building for Subversion 1.5.  There has been a lot of good feedback from users who have downloaded and tried that client.

This week, we are introducing a preview of an extension to the merge client that allows you to perform merges based on change sets.  With this extension to the merge client, users of CollabNet Enterprise Edition's Project Tracker can perform merges by specifying Project Tracker artifacts as the input to the merge process instead of having to specify a list of revisions.  This is a really easy way to perform certain types of merges and can lead to some interesting new workflows and business processes.

If you have already installed the merge client, you can just visit the same installation site and grab the change set extension.  I have also written an overview of the client that has some more details and screenshots.  Click here for the overview of the change set extension.

While you will need Subversion 1.5 on your server to get the full benefits of merge tracking, the bulk of the features of this change set extension can be used today with your version of CollabNet Enterprise Edition.  So give it a try and let us know what you think.

It has been a busy few months for the Subversion engineering team at CollabNet and the Subversion community in general. As we detailed in many posts this summer, the entire team is hard at work on Subversion 1.5, specifically the merge tracking feature. 

Back in the spring we started the Merge Tracking Early Adopter Program on openCollabNet. We wanted to make it as easy as possible to get people to try early versions of the merge tracking code and provide feedback to CollabNet and the Subversion community. The program has been pretty successful and provided some valuable feedback that was incorporated into the merge tracking deliverables for Subversion 1.5. Last week we refreshed the Subversion 1.5 Beta binaries on the merge tracking site to a more recent version in order to spawn a new round of testing. If you have not already downloaded them, please download them and give them a try. It is not too late to help the community deliver the 1.5 release.

The title of this post is "Subversion merge made easy" and that brings me to an announcement of sorts. While all of the work on Subversion 1.5 has been going on, another team at CollabNet has been working on a new GUI merge client for Subversion. Today we are releasing a beta version of this client as part of the Merge Tracking Early Adopter Program. A lot of work went into this client and there are many features. Rather than listing them here, let me instead link to the documentation on the merge tracking site.  The documents explain how to install the client and give an in depth overview of its features. I encourage you to download the client and give it a try. Use the forum of the merge tracking project to provide feedback, ask questions, report problems etc. If you try the client, you will automatically also test the Subversion 1.5 merge tracking feature, which can only help to accelerate its release.

Finally, since we are talking about merge and making it easier, I just want to also mention an upcoming webinar that is being presented by two of my colleagues at CollabNet -- Bob Jenkins and Auke Jilderda. They have both contributed a lot of ideas and feedback to the merge tracking feature as well as assisted in putting together the merge tracking early adopter program on openCollabNet. Their webinar is sure to be stocked with valuable insights on branching and merging in Subversion.

There are a couple of cool events going on around Subversion, online and offline.

Branching and Merging for Subversion 1.5 Webinar

With Merge Tracking coming, many companies will want to have a fresh look at their branching strategies. We often hear that people hold back on branching because they are waiting for Merge Tracking. Now you don’t have to hold back anymore but you do need to prepare and make sure that when you upgrade to Subversion 1.5, you implement policies that optimize parallel development on multiple branches.

On September 26th CollabNet organizes a webinar on branching strategies, in cooperation with CM CrossRoads. We’ll explain how to develop and implement branching policies that best fit your organization and Auke Jilderda and Bob Jenkins will show how to use Subversion 1.5’s Merge Tracking functionality to support parallel development on different branches. You can sign up here (it is free).

Other webinars

We actually do regular live demos of Subversion and are updating them to include the new features of Subversion 1.5. The next one is October 9th.

Another great webinar to sign up for is “Round Trip Engineering” on Tuesday September 18th with Nick Gulrajani. Subversion is of course only one piece of the development tools puzzle and how the pieces integrate has a big impact on your productivity (and stress levels). Nick will show how seven different tools integrate and how many of them can come together in your IDE through plug-ins.

Subversion conference and workshops

The first-ever Subversion conference, Subconf 2007, will take place in Germany, October 16th to 18th (its own conference, quite a milestone for Subversion). English-language information is at http://www.subconf.com. Some sessions will be in German (like customer success stories from local companies) but there is enough in English to make it worth everybody’s while. A number of Subversion committers will be at the conference (and not only CollabNet's), so come and meet them.

I specially want to point out CollabNet’s workshop on October 15th: the “Definitive Subversion 1.5 Workshop”. It’s all about Subversion 1.5, including Merge Tracking, and the presenters include Subversion committers. This should be a great one to be at.

Hope to meet you at any of the above svn events

Subversion 1.5 will support Merge Tracking. This blog post provides a high level overview of what Merge Tracking is, why it is important and what it means to your organization. I'll begin with some very basic explanations; if you are familiar with branching and merging, skip paragraph 1.

1. What’s branching and merging?

Development teams often work on several parallel lines of development, called ‘branches.’ A branch starts with making copies of all the files of your development project (or a directory) and maintaining these copies separately as you go forward. Files start as identical copies but over time they will differ from each other as developers make changes on the different branches.

Why branch? You might create a branch in Subversion for the maintenance of a released product while simultaneously working on the next release. Why? The next release will have new features but on the maintenance branch you only accept bug fixes. Another use case is the development of a complex new feature that you know will destabilize your development builds. By doing that development on a separate branch, you isolate the other developers from the disruptive work that would break nightly builds for everybody. Subversion’s own Merge Tracking feature was developed on a branch for about a year.

Graph 1. Mainline development (trunk) with two branches

Subversion has always supported branching and unlike many other systems it does not actually copy the files, which would rapidly grow the size of the repository. Instead, Subversion creates a quick reference to the existing directory and from there on just tracks the changes to the files on the branch and trunk. The result is that creating a branch is very quick and the repository hardly grows in size.