I have a local SVN server running on my machine. In it I have a repository containing some default /wp-content stuff, that I use for every project(default plugins, default theme framework, etc). Today I just remembered that instead of having each plugin's files in my repo, I can use svn:externals to fetch the latest files of each plugin.
That's good, but there is one problem - not all plugins' stable tag is /trunk - so I would possibly end-up with a development version(that is in /trunk), instead of the stable version, specified by the stable tag in the readme.txt.
So my question is - is there a way to get the stable tag, whatever it is, using svn:externals(or anything else anyway - when I think about it now, I might be able to run a shell script that will check each of the plugin's stable tag and update the repo accordingly).
Plugins hosted at WordPress.org need to have a file called readme.txt that's formatted in a particular way. See this: http://wordpress.org/extend/plugins/about/readme.txt
One of the tags near the top of readme.txt is Stable tag:.
When a Wordpress.org blog administrator goes to download a plugin, wordpress.org looks in svn at trunk/readme.txt, grabs the stable tag, then gets the plugin from tags/stable-tag/
So developers releasing updates need to create a new stable tag, then change the readme.txt and check it into the trunk.
I don't know if you can pull off this behavior with svn:externals. But it's worth a try.