On April 24th, the Subversion development community released the first official release candidate for Subversion 1.5.  You can see the official announcement in this mailing list post.  You will notice that this release is labelled as RC4, and you might be wondering if you missed the RC1-3 announcements.  The answer is no, this is the first official release.  We go through an internal review period before we post any release.  Committers build and test the release and then either vote to approve or veto the release candidate.  In each of the first three tries someone saw something they did not like and so we vetoed the release.  Since version numbers are cheap, we simply increment when we try again.  That way, there is never any confusion about what someone is using.

Anyway, this is the biggest milestone for the release, short of the final GA.  The release of this release candidate can start the official soak period, which lasts a minimum of four weeks.  You can read about our release-stabilization process in the hacking guide we host on the web site.  As part of getting to this release candidate stage, we now have the release notes finalized, and you can see those online as well.  There is a lot of good overview information about the release in that document.

As we have been doing throughout the 1.5-development lifecycle, CollabNet is providing binaries for this release.  We want to make it as easy as possible for users to test the release and provide us with feedback.  Please provide the feedback, including positive feedback, as it helps us know that people are actually testing the release candidate during the soak period.  Sometimes if we do not get much feedback we will extend the soak period a little longer in order to allow time for people to try it.  So if you find bugs, please report them, and if things are working out well, then tell us that too so that we know you tried it.  Feedback can be reported on our forums on openCollabNet, or on the Subversion users mailing list on tigris.org.

In addition to getting the Subversion binaries, you can also try our new graphical merge client for Subversion 1.5 (based on Subclipse) and we also have links to the 1.5 release for TortoiseSVN and other tools.  It would be great if you could also try these tools out and give us and the developers your feedback.

CollabNet now hosts and supports AnkhSVN, the Subversion plugin for Visual Studio. Some of our goals are to help the AnkhSVN community grow and accelerate the development of the plugin. To kickstart this, we started by collaboratively creating a roadmap for AnkhSVN. Subversion 1.5 compatibility is number one on that roadmap, including good merge support. To properly support Subversion 1.5, we either needed to update our internal C# Subversion binding (NSvn) or take advantage of SharpSvn, a .NET binding for Subversion. We chose the SharpSvn route. To understand why, let's learn more about SharpSvn.

SharpSvn is a project started by Bert Huijben, who is also an AnkhSVN committer. The purpose of SharpSvn is not only to bring Subversion's API to .NET but also to abstract the low-level Subversion API away from the developer while still conforming to Microsoft's common language specification. The result is that SharpSvn is a Subversion client binding for .NET that works with a .NET 2.0 application or newer.  (Note: Since Subversion 1.5 and its final API is not yet complete, SharpSvn's APIs can change before the final release.) 

To show the value of what SharpSvn can bring to any .NET-based Subversion application, I created a simple Subversion Log Viewer using SharpSvn.

When you download and view the Log Viewer source, you'll see a lot of code that is primarily related to the UI and threading. I only use a few of SharpSvn's classes:

 
• SharpSvn.SvnTarget: Use this class as a target to run Subversion functionality against.
 
• SharpSvn.UI.SharpSvnUI: This class provides access to SharpSvn's built-in UI, for example when you are prompted for credentials or need to accept an SSL certificate.
 
• SharpSvn.Client: This is the actual client abstraction that gives you access to Subversion client functionality.
 
• SharpSvn.SvnLogEventArgs: Use this class to handle the events returned by SvnClient.Log().
 
• SharpSvn.SvnChangeItem: Use this class for objects that hold information about changed items retrieved via SvnClient.Log().

And here is a major part of the SharpSvn code in the example:

/// <summary>
/// Retrieves the Subversion log entries and potentially updates the
/// DataGridView in a streaming fashion.
/// </summary>
private void retrieveAndRenderLog()
{
    .....
    // The Subversion target to run log against
    SvnTarget target;
    
    // Attempt to create an SvnTarget by parsing the targetPath
    if (string.IsNullOrEmpty(targetPath) ||
        !SvnTarget.TryParse(targetPath, out target))
        {
            .....
        
        // SvnClient is disposable, using makes sure it's disposed every time
        using (SvnClient client = new SvnClient())
        {
            // Bind the SharpSvn UI to our client for SSL certificate and credentials
            SharpSvn.UI.SharpSvnUI.Bind(client, this);
            
            try
            {
                // Run the log subcommand
                client.Log(target,
                delegate(object lSender, SvnLogEventArgs le)
                {
                    .....
                    // Iterate over each changed path for each log entry
                    foreach (SvnChangeItem path in le.ChangedPaths)
                    {
                        tooltip.AppendLine("");
                        tooltip.Append(path.Action + " " + path.Path);
                        
                        if (path.CopyFromRevision != -1)
                            tooltip.Append(" (" + path.CopyFromPath +
                                "[" + path.CopyFromRevision + "])");
                    }
                    ..... 

SharpSvn is very performant and a simple to use API when writing .NET-based Subversion applications.  It is  easy to figure out what classes/APIs are necessary to get things done and the documentation in the SharpSvn project, and help provided on #ankhsvn (the irc.freenode.net channel for AnkhSVN), allowed me to put together the example application in less than an hour.  You will also be happy to know that SharpSvn alleviates the need for you to manually maintain the authentication callbacks, baton objects, aprpools and other low-level things that you are left dealing with while using other language bindings.

The SharpSvn's client API is completely in sync with the Subversion 1.5 client API and is the core of the future AnkhSVN 2.0 release. The code quality and completeness of SharpSvn is impressive. If you want to get involved with the development of SharpSvn, visit the project on openCollabNet.