I was recently working with someone who was using Zend Framework in their
project. To keep things stable and releasable, he was doing an export of
framework into his repository and checking it in. Since files change so much
in the ZF project currently, instead of doing an rsync from a checkout into
his own repository, he decided instead to delete the directory from the
repository and re-add it everytime he was updating framework.
This seemed really inefficient to me, especially considering that it made it
incredibly difficult to merge changes from his development branch into his
production branch (deleting and re-adding directories breaks the merge
process considerably). I knew there had to be a better way.
I'd heard of the svn:externals property before, but never really played with
it. As it turns out, it exists for just this very type of situation. The
problem is that the
documentation of svn:externals
in the SVN book doesn't indicate at all how the property should be set, and
most howto's I've read omit one or more very important details. I finally
figured things out through some trial and error of my own, so I'm going to
share the process so others hopefully can learn from the experience as well.
It's actually pretty easy. This assumes that your project layout looks
something like this:
project/
branch/
production/
tag/
trunk/
One thing to note: any directory you specify for an svn:externals checkout
should not already exist in your repository. If it does, you will get
an error like the following:
svn: Working copy 'sharedproject' locked
svn: run 'svn cleanup' to remove locks
I show using revisions above; you could also pin to tags by simply checkout
the external repository from a given tag. Either way works well.
Then, when moving from one branch to another, or from the trunk to a branch,
you simply set a different svn:externals for each branch. For instance, your
current production might check from one particular revision, but your trunk
might simply track head; you then simply determine what the current revision
being used is on your trunk, and update svn:externals in your production
branch when you're ready to push changes in.
Hope this helps some of you out there!