M²APSubversion HOWTO

5. Meaning of the Prefix Letters

Below are some of the more common letters that one encounters during the daily usage of svn and their meanings.

• 'A' -- Addition
• 'D' -- Deletion
• 'C' -- Conflict exists with this file
• 'G' -- Modifications have been merged successfully
• 'M' -- File has been modified since last svn update
• 'R' -- Replaced
• '?' -- Not in repository, svn doesn't know about it

6. Creating a New Repository

6.1. A new code development repository

Suppose you want to create a new svn project repository, let's call it auv. Firstly create 2 folders, "trunk" and "branches" in your auv project folder. Then move all your source files into the trunk folder. Then issue the following commands in the example shown:

Explanation of the above commands: Our server is Ubuntu which is a Debian derivative. The user id that accesses the svn repository via the Apache http protocol is given by the default: www-data. So by initially creating the project folder and importing the files as the user www-data, this eliminates the additional step of having to setup proper permissions for group and others.

Your newly created svn repository is now ready for check out at the URL: http://bigbird.comp.nus.edu.sg/motion/proj/auv/
Note: auv is the example project folder here, remember to change auv to the name of your project. Please send us an email if you still encounter permission problems, koksung or zhanwei

6.2. A new paper project directory

As the paper directory is setup to have only one repository, the most straightforward way to create a new paper directory is to issue the following command:

Alternatively, one may also first check out the trunk of the paper, i.e. http://bigbird.comp.nus.edu.sg/motion/paper/trunk/ and then in your local copy, issue "svn mkdir <name of paper project>". Lastly, do a svn check-in to commit the creation of this new paper project directory.

Remember, the command to issue is "svn mkdir" and not "mkdir", the latter only creates a local directory whereas the former will direct svn to create a project directory at the paper repository the next time you commit changes.

7. Deleting a File in a repository

Note that svn's design philosophy is "Make local changes, commit for global effect". This applies to almost every possible actions. E.g. to delete a file, you will delete your LOCAL copy and then commit, to sync the svn server.

Issue the following commands to delete a file. Notice the line: "D AUVPomdpgenerator.py", the letter 'D' means the file is scheduled for deletion and it will take effect the next time you commit changes.

8. Adding a File to subversion control in an existing repository

The scenario: suppose you have checked-out a repository, you created a file and would like to add it to subversion control to this existing checked-out repository. Follow the steps below. Notice the line:"A aNewFile.txt", the letter 'A' indicates that the file has been made known to svn and it will be added to subversion control during the next commit. Once again, svn's philosophy: "Make local changes, commit for global effect".

9. Deleting an entire repository

Deleting an entire repository is different from deleting a file. For this, we can remote login to the svn server (i.e. bigbird) and remove the entire project folder as the user www-data. This is the most straightforward way.

10. Update Local Copy from Server

To update your local copy, use svn update

11. Commit Changes Back to Server

After you have made changes to the local copy. You need to commit changes back to Server so that others can see it. Go the directory that you would like to commit, then:

12. Branching

Suppose you would like to branch off the project for some private development, this can be easily done in svn---you make a copy of the project in the repository using the svn copy command.

Now that you've created a branch of the project, you can check out a new working copy to start using it. The check out command is as mentioned above. There's nothing special about this working copy; it simply mirrors a different directory in the repository. When you commit changes, however, others won't see them when they update, because their working copies are of /auv/trunk.

13. Tagging

Suppose you reached a significant milestone in the development of the project and want to save a snapshot of the current repository.

This is the same copy command you used for branching. By convention, it should copy to the "tags" directory of the project.

14. Merging From Trunk to Branch

Suppose that you have made some bug-fixes on the trunk, and you would like to apply those to your branch too.

There may be some conflicts. After resolving these conflicts manually, you need to commit these changes back to server.

15. Reintegrate Branch back to Trunk

When a branch is mature enough, you may reintegrate the branch back to trunk. The result is to make the trunk identical to the branch.

Note: Remember to merge all bug-fixes from trunk to your branch first. And email everyone before reintegrating branch back to trunk.

Resolve possible conflicts, then do a commit