I’m a happy Subversion camper, I use it for all my personal projects. There’s one thing I don’t get about it though: tags. In CVS (or Perforce, or many other systems), I can create a tag (or a label as it is called in some systems). It’s a symbolic name for a set of revisions of files. In Subversion, it would be a symbolic name for a revision of the repository.

Subversion provides tags, but is gleeful about how they are implemented with the copy command: a tag is simply a copy of a particular revision of a tree into another part of the repository. The typical instructions for setting up Subversion say to create three directories at the top: trunk, branches, and tags. The tags directory is to hold the eventual tags you will create.

OK, so I understand this, and I understand that making a copy doesn’t really copy anything in the repository until the files are changed. And since this is a tag, the files will never be changed there, so the copy really is small in terms of space. But what happens to my working directory? If I ever go into the tags directory and use the update command, I’ll pull out a copy of every file that has ever been tagged, once for each tag!

Is this right? I know I don’t want to keep all those copies, so I can delete the working directories in my tags directory. They’re still in Subversion, and the “svn ls” command will show them to me. I can pull out the ones I want with “svn up tags/SomeTagName”. But I feel uneasy with “svn up” potentially pulling out a pile of files I don’t really want. Is there some other step I can take to keep the genie in the bottle?