The Apache Foundation last week released version 1.7 of the Subversion file-based SCM system, with a rewrite of the metadata management system designed to boost performance, and a more efficient HTTP protocol (HTTPv2) that is faster and reduces roundtrips from client to server.
“If people are completely happy with Subversion today and are looking for new features, there aren’t a lot of bullet points” with this release, according to Mike Pilato, a software engineer with CollabNet, which contributes to the Apache project. “These are mostly plumbing changes under the hood for increased performance.”
But the big news for Subversion is not coming out of Apache. Developers at WANdisco, which sells a commercial version of the SCM system, and SaaS provider Assembla are working on a new merge capability for Subversion.
The merge capability represents “a major change in how Subversion works,” said David Richards, president and founder of WANdisco. With the Git distributed version control system, workflows can be set up that enable team members to work on different things and merge them all together, he explained. The downside, he said, is that “with Git, you’re always working with the entire repository,” because a distributed VCS requires data to be replicated across every client.
Richards said the company is working on a client-side fork-and-merge application that “relieves the stick that the Git faction is beating Subversion with.” But he said that the effort is not merely to take an argument away from Git supporters; it will be an option that is compatible with Subversion 1.7, not a requirement. Richards said WANdisco expects the new merge functionality to be released into beta in about three months.
According to Sesha Pratap, cofounder of Assembla, the new merge capabilities will appear in both Assembla’s Subversion service offering and WANdisco’s product. The companies will make the capabilities available to Apache, which will then have to vote on whether or not to accept the work into the open-source project.
Gartner analyst Jim Duggan, who follows the SCM space, said the new merge will actually bring Subversion closer to other commercial file-based systems such as AccuRev, Perforce and others. “I don’t think this release addresses the fundamental disconnect between distributed VC systems and file-based systems,” he said.
As for the 1.7 release, the Working Copy-Next Generation codename for the metadata management system brings centralized metadata storage for improved performance. “We did a complete overhaul of the entire working copies library that manages all client state,” said CollabNet’s Pilato.
As for HTTPv2, Pilato said the project team has moved away from WebDAV and its DeltaV versioning. “We still support [WebDAV and DeltaV] on the client-side, but we’re taking advantage of the extensible part of the protocol to reduce network turnarounds across HTTP,” he said.