SubConf 2009 — A Report (Day 2)

12:05 pm – 12:50 pm

Bringing Subversion to the Java(TM) World — Alexander Kitaev and Alexander Sinyushkin

Alexander Kitaev and Alexander Sinyushkin are from TMate Software and work extensively on SVNKit (they are the core developers of SVNKit). Alexander Kitaev explained how SVNKit makes it easy for Java developers to interact with Subversion.

Some of the key points are as follows:

1. SVNKit uses pure Java Approach
2. SVNKit does not support BDB but works with FSFS
3. Subclipse has a switch to choose between SVNKit and JavaHL attributed to Mark Phippard (mphippard) who made it possible.

02:15 pm – 03:00 pm

WC-NG (Subversion’s new Working copy management library) — Hyrum Wright

Hyrum Wright is the Release Manager of Subversion project and President of Subversion Corporation. WC-NG stands for Working Copy Next Generation library. This talk discussed about the history of working copy library in the subversion code base which is almost 10 years old, how the rewrite of wroking copy libraries will aid further feature development of subversion features in future with ease.

Key features of WC-NG:

1. Centralized metadata
2. More sane set of developer APIs
3. Making hard easy; the impossible possible

The following are some of the questions posted by audience at the
end of the talk and responses:

Q1. If WC-NG is for 1.7, then what will be there in 2.0?
Ans: Definition for 2.0 is breaking compatibility which WC-NG tries to avoid, hence it finds a place in 1.x release.

Q2. How will WC-NG impact performance?
Ans: Running tests on 1.6.x subversion takes around 25 minutes (in a decent machine of 21st century), on the other hand it takes close to 30 minutes in trunk (has some basic WC-NG stuff up), which is close to the existing numbers and good! We expect a great improvement in speed when we are close to completion.

Q3. ‘svn upgrade’ support for older versions of svn wc formats?
Ans: We have plans to provide upgrade paths from different old wc formats such as 1.2.x to 1.7.x, 1.4.x to 1.7.x, etc.

Q4. When will it be finished?
Ans: Will be finished in 1.7. More appropriately some time next year. The Subversion Hackathon, which happens as a part of SubConf, is to facilitate discussion of WC-NG end game.

03:05 pm – 03:50 pm

Comparing Apples to Oranges – Subversion, Git and Mercurial by Stefan Sperling and Stephen Butler

Stefan Sperling and Stephen Butler are Subversion hackers and employees of Elego Software Solutions. In this talk, they took 4 real life situations to illustrate how different version control systems scale.

Key Features

1. Reserving a file for editing – Centralized vs Distributed
2. Merging a text edit to a renamed file – How is tree history modeled?
3. Merging a file move – Distinguishing file move from directory rename
4. Cherry-picking a revision – Fine-grained merge tracking

The following are some of the questions posted by audience at the end of the talk and responses:

Q1. What can Subversion learn from Mercurial and Git?
Ans: Merge just works in mercurial and git, but subversion merge needs more improvements though it offers much flexibility to users.

Q2. Authorization problem in DVCS?
Ans: You can enforce authorization in DVCS by writing various scripts and defining rules in an ad-hoc manner, unlike subversion where everything works out of the box (may be closely).

04:15 pm – 05:00 pm

Moving from SVN to Mercurial — Zsolt Koppany and Janos Koppany

Zsolt Koppany and Janos Koppanyare CTOs of Intland Software. This talk discussed about various prospects Intland Software and their customers saw by moving from SVN to Mercurial which adapted naturally to their workflow.

05:05 pm – 05:18 pm

Server Side Java bindings for Subversion — Dave Brown (Employee of WanDisco)

This talk discussed about SVN-J which is an effort in coming up with a new implementation to provide a native Java implementation of Subversion Server side bindings. This project is still in its pre-alpha and go public shortly, which invites developers to contribute in all aspects. They also plan to replace mod_dav_svn with java bindings to Tomcat.

05:20 pm – 05:55 pm

SVN Obliterate by Julian Foad (Long term subversion developer and Employee of WanDisco)

Julian explained about the various design goals of SVN Obliterate and introduced the plans of how Obliterate may get implemented in the subversion code base. He also touched upon the reasons for including or excluding certain features from implementation of svn obliterate.

Q. ‘svnsync’ will know about obliterate?
Ans: Ideally it should, but right now there is no plan for implementing it in the initial phases of svn obliterate development.

Thus there were a lot of informative talks regarding subversion. The above is not a complete log of all that happened as a part of second day of SubConf, but I tried my best to capture the key points as much as I can from the sessions.

There is one more day of SubConf 2009, keep watching this space for updates!

Click here for the Day 1 Report of SubConf 2009