HOWTO Start working with Subversion

From Consultancy.EdVoncken.NET

Subversion, one of the popular Version Control Systems, is quite easy to set up. In this example, I'll create and initialize a locally hosted repository. Make sure you read Version Control with Subversion - it is free, and I highly recommend it!

Repositories

I decided to store my Subversion Repositories under my home directory. Since I work for multiple customers, I want to give them independent repositories to keep the work isolated. For Customer1, everything can go into one repository (no projects needed):

 $ mkdir -p /Users/ed/svnrepos/
 $ svnadmin create /Users/ed/snvrepos/Customer1

Customer2 requires the use of separate repositories for each of their projects, so I need to add another directory level:

 $ mkdir -p /Users/ed/svnrepos/Customer2
 $ svnadmin create /Users/ed/snvrepos/Customer2/ProjectA
 $ svnadmin create /Users/ed/snvrepos/Customer2/ProjectB
 $ svnadmin create /Users/ed/snvrepos/Customer2/ProjectC

Workspaces

Create Workspaces

You should never work directly in the Repository - all work is done in "Workspaces" (local copies of the Repository). I keep these workspaces under my Documents/Work directory on Mac OS X:

 $ cd /Users/ed/Documents/Work
 $ svn checkout file:////Users/ed/snvrepos/Customer1
 Checked out revision 0.
 
 $ mkdir -p /Users/ed/Documents/Work/Customer2
 $ cd /Users/ed/Documents/Work/Customer2
 $ svn checkout /Users/ed/Documents/Work/Customer2/ProjectA
 Checked out revision 0.
 $ svn checkout /Users/ed/Documents/Work/Customer2/ProjectB
 Checked out revision 0.
 $ svn checkout /Users/ed/Documents/Work/Customer2/ProjectC
 Checked out revision 0.

Set up trunk/tags/branches

According to Best Practices in svn-book 1.5 (pdf), I use the standard "TTB" directories in each of my repositories:

 $ cd /Users/ed/Documents/Work/Customer1
 $ svn mkdir trunk tags branches
 A         trunk
 A         tags
 A         branches
 
 $ svn commit . -m "Created initial repository layout"
 Adding         branches
 Adding         tags
 Adding         trunk

The contents of your working copy and repository are now in sync:

 $ ls -l
 total 0
 drwxr-xr-x  3 ed  staff  102 Apr 21 12:36 branches
 drwxr-xr-x  3 ed  staff  102 Apr 21 12:36 tags
 drwxr-xr-x  3 ed  staff  102 Apr 21 12:36 trunk

Do the same for the other repositories:

 $ cd /Users/ed/Documents/Work/Customer2/ProjectA
 $ svn mkdir trunk tags branches
 $ svn commit . -m "Created initial repository layout"
 
 $ cd /Users/ed/Documents/Work/Customer2/ProjectB
 $ svn mkdir trunk tags branches
 $ svn commit . -m "Created initial repository layout"
 
 $ cd /Users/ed/Documents/Work/Customer2/ProjectC
 $ svn mkdir trunk tags branches
 $ svn commit . -m "Created initial repository layout"

Done! Now, you should switch to the proper trunk, tag or branch before adding files or directories to your workspace.

Switching between trunks, tags and branches

To reconfigure your workspace for a particular trunk, tag or branch, use the svn switch command from inside your workspace:

 $ cd /Users/ed/Documents/Work/Customer2/ProjectA/
 $ svn switch /Users/ed/snvrepos/Customer2/ProjectA/trunk

Branching and Merging

Branching

Let's say you you suddenly need to make an important change, without impacting the main line of development. This is where "branching" comes into play:

 $ svn copy file:///Users/ed/snvrepos/Customer2/ProjectA/trunk file:///Users/ed/snvrepos/Customer2/ProjectA/branches/CR20090420

You now check out the newly created branch, for example in a fresh workspace (you can have as many as you like...)

 $ cd /Users/ed/Documents/Work/
 $ svn checkout file:///Users/ed/svnrepos/Customer2/ProjectA/branches/CR20090420 CR20090420

This will create a workspace in /Users/ed/Documents/Work/CR20090420. Now, you can edit/add/remove files or directories, implementing the Change Request.

To review your changes, use the "svn status" command:

 $ svn status
 M      bar.c
 ?      foo.c
 ?      foo.h

We created two new files, so let's add those:

 $ svn add foo.c foo.h
 A         foo.c
 A         foo.h
 
 $ svn status
 M      bar.c
 A      foo.c
 A      foo.h

Good. Let's commit the changes in this branch to the repository:

 $ svn commit . -m "Implemented CR20090420: Added new feature foo"
 Sending        CR20090420/bar.c
 Adding         CR20090420/foo.c
 Adding         CR20090420/foo.h
 Transmitting file data ...
 Committed revision 7.

Merging

Once your change has been tested and approved, it should probably be incorporated in the main development line, (usually /trunk). To do this, we will merge the changes in the CR20090420 branch (revision 7) back to the trunk.

We need to change to a workspace that contains the /trunk (or switch an existing workspace to /trunk):

 $ cd /Users/ed/Documents/Work/Customer2/ProjectA/

Before doing the actual merge, do a dry run to see if the results match your expectations:

 $ svn merge --dry-run file:///Users/ed/svnrepos/Customer2/ProjectA/branches/CR20090420

If all seems well, run the actual merge:

 $ svn merge file:///Users/ed/svnrepos/Customer2/ProjectA/branches/CR20090420

If you encounter merge conflicts, you may need to resolve them manually. Afterwards, you will need to tell Subversion that the conflict has been resolved, for example:

 $ svn resolve --accept=working foo.c

Otherwise, "svn commit" will complain and refuse to proceed.

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