SVN for School Projects

What is svn?

svn (Subversion) is a source code repository. It is a program capable of storing the source code of a project and keep track of all the changes made (contributions) by its developers.

What svn can do for you?

• Stores your work (source code) safely on a remote server so you will never lose your work.
• Lets several students work on the same project at the same time.
• Keeps track of all the work done with history (who have done what, and when), this means you can:

  undo your work to any of the past stages of the work.

  look at different stages of the work and see all the changes.

  check other team members' work, their progress and contribution.

  ask for help from others to help you with your work and help others with their work.

• to be continued...

Common actions for school projects

Kick-start a project (project initiation)

1. create a directory to do your work
2. checkout the repository (the whole thing) into the directory

   Look and make sure you have the 3 directories (branches, tags, trunk)

3. Open branches directory and create a directory using your login name

   this becomes the root of your (each students') workshop

   note: do not use the operating system's file management to copy, move, etc any of the versioned files

4. Do an update on the whole repo to see all the changes from all students
5. branch the trunk into a sub-dir of your workshop (name the sub-dir using your assigned task)

   branch as verb, means copy (in repository)

You are good to go to start working on your repository

Start working on a project (Start a task)

1. If you have not already branched the trunk:

   branch/tag the trunk into a sub-directory. Use your task name/description to Name this sub-directory so you can refer to it easily later.

2. In your branch/task directory do your work and commit anytime you have something worth committing. Make sure you comment your commits.

   Note that in your branch you can commit your work even if it is not complete. In fact, commit your work anytime you are leaving your computer and comment it like: "going for lunch". But again this is only valid when you are working in YOUR OWN BRANCH

3. When task is complete
   1. Update the repository to get all the changes applied to your local copy
   2. Merge the changes back to trunk

   Note that, the merging happens on the local copy and not the repository

4. Edit possible conflicts, save and mark them as resolved when done.
5. Compile the trunk, test and make sure the changes are what you want
6. In trunk, apply more changes and do debugging if needed.

   note that this is the only time you do work in trunk

7. When everything is perfect get ready to commit the trunk:
   1. Make sure you are logged in to IRC.
   2. Go to team page and set the status of trunk to committing with following info: User ID, email, IRC Nick, time and date
   3. If the status of trunk is already committing by another user, communicate with them and find out when they are going to be done so you can do your commit.

      Never commit to trunk with out checking and setting the status of trunk in your team page

   4. Update repository
8. Commit the trunk
9. Edit, save and resolve possible conflicts and go to previous step
10. When done, go to team page and set the status of trunk back to committed with the same info as before.

Continue working on a task on a new computer (public computer)

1. Checkout only your branch/task
2. start working on your task and keep committing the changes as you go.
3. when done, do final commit, stating the work period is done
4. Delete the checked-out directory from the public computer.
5. Reboot the computer

   this will remove your userid and pass if you have chosen to save them.

   Note that you are responsible to keep you work safe, if someone gain access to your code and repository, YOU are responsible for it and its consequences.

Continue working on a task (everyday work)

1. Update repository to get the final changes.
2. (optional and only if needed:) If trunk is updated by someone else since the time you branched it, you can merge the updated trunk into your branch to get the latest additions and modifications of trunk in your branch.
3. Continue working on your task and keep committing often.
4. when done for the time, commit your work and comment, stating at what stage you are.

Release a completed task (Submitting an Assignment or a Release)

1. This is when a major task is accomplished and it is time to present it to your professor.

   This is not necessarily to hand in a new release. It could be at any time you feel you are one step closer to the end of the project.

2. Update and make sure the trunk has the latest modifications.
3. Do all possible changes and fixes to make this release final.
4. tag (branch) the trunk into a sub-directory in tags.

   Name the tagged directory relative to its state (i.e. name it R0.4 and comment it with task name Text Editor)

   If this is a fix to a previously released trunk, add the release revision after the release number: (i.e R0.41 and comment it as Fixed backspace bug in Text Editor)

5. your prof will later update the repo and get the Release.

Standard svn tree structure

Directory Structure

|-- Team_Repository_Account
  +--branches
  | +-- member-id1  <-- this is a team member's home within branches
  |   +-- Task1
  |   +-- Task2
  | +-- member-id2  <-- this is a team member's home within branches
  |   +-- Task1
  |   +-- Task2
  |   +-- Task3
  | +-- member-id3  <-- this is a team member's home within branches
  |   +-- Task1
  +--tags
  | +-- R0.1
  | +-- R0.11
  | +-- R0.2
  | +-- R0.21
  | +-- ...
  | +-- R0.5
  | +-- ...
  | +-- R1.0
  | +-- R1.1
  | +-- R1.2
  | +-- R1.21
  +--trunk

branches

• branches is the common directory for all team members' workspaces.
• Each team member should create their own home directory or workspace (member-id1, member-id2,...) for their own development tasks within branches.
• Each team member should divide their workspace into several sub-directories (workspaces) during the development of the project. These workspaces(Task1, Task2, ...) are usually copies of the trunk to be worked on.

  These sub-directories(Task1, Task2,...) are called branches of trunk. When the word branch is used as a verb, it means copying the whole trunk into a sub-directory, in branches.

tags

• tags is the directory that holds copies of successful stages of trunk throughout the development of the project. (Also called as Milestones)
• tags are never modified or edited. You may branch a directory of tag into branches under a workspace and then modify the branch and apply the changes back to trunk, but you should never change the contents of a tag

  When the word tag is used as a verb, it means copying the whole trunk into a sub-directory, in tags.

• The action of taging the trunk into tags is often referred to as a release.
• We use the tags directory to submit the work for marking. Your instructor will specify the requirements of a release.
  • A release is usually tagged by a version number like: R0.1, Prj0.2, As1_1.0
  • When a release is due, your instructor will always mark the latest version of that release.

    If R0.3 is due, and R0.3, R0.31, R0.32 are present in tags, then your instructor will mark R0.32

trunk

• trunk is the directory that holds the project in its current stage, complied and run-able
• trunk should never hold non-compiled code. Usually trunk is an exact copy (or better than) the latest version in tags.
• If the repository only contains one project, then trunk has no project level sub-directory and is the root of the project. If the repository holds more than one project, trunk is divided into several sub-directories - one for each project.

  In this case, we divide tags into exactly the same project sub-directories as present in trunk

Svn basic commands

A few important facts and terminology to help clarify the basic actions:

• A code repository is to keep track of all of the modifications done to a project by its team members.

  In a project that is tracked by a code repository (version-controlled or in short versioned), you can focus on any changes during the project's development life; such as, who modified/added/deleted what and when. You can undo work or rollback the work to any stage of the development and much more.

• SVN is a client/server repository;
  • Code is kept on a server and those members who have access can copy the whole or parts of the project to their local machines, work on the whole or parts and then apply their changes back to the server.
  • Because the code is kept on a server, one member may be unaware of the changes made by another member, unless the other has applied the changes to the server and the member has update their local copy.

    That is why timely and often communication between team members is highly vital for the success of the project. This can easily be accomplished through the project wiki page (team page) and IRC

• A code repository manages merging the modifications of different members' code. However this may fail and as a result the repository will sometimes be in a conflict state.

  Conflicts can easily be edited, saved and resolved using the tools provided by SVN.

• A Version-controlled or versioned file is a file that is handled and tracked by a repository.

checkout

To checkout is to download the code from a repository server as a whole, or partial, to a versioned directory on the client, so that you can start working on the code.

• GUI:

1. Create a directory on your local machine
2. Right click on the directory and select SVN Checkout
3. Enter the path of the repository or a sub-directory inside the repository and click OK
4. Enter userid and password if needed

• Command Line:

svn co svn://zenit.senecac.on.ca/repoid local_directory --username stdId --password stpassword
OR
svn checkout svn://zenit.senecac.on.ca/repoid local_directory --username stdId --password stpassword

commit

commits (submits) the changes in the local files to the repository (on server)

• GUI

1. Right click on the directory or file to which you made modifications and click on SVN Commit
2. In Commit Dialog box write a short description (few words) to explain what is modified and is being committed and click on ok.

• Command Line

svn commit locdir\branches\stdId\SomeDirectory 
 -m "Added comments to foo() in faa.cpp and fee() in boo.h"

OR

svn commit locdir\branches\stdId\SomeDirectory\somefile.cpp
 -m "Added comments to foo() is somefile.cpp"

update

Downloads and applies the modifications made by others from the repository (on the server) to the local files (on your computer)

• GUI

  Right click on the directory or file (that you want it to be updated) and click on "SVN update"

• Command Line

  while in the local directory

svn update

OR from anywhere

svn update LocalDirecotyPath

OR for a single file

svn update LocalDirecotyPath/somefile.whatever