I recently had occasion to add a dependency on a Git-hosted project to a Subversion-hosted one. After adding support for an ad-hoc "git:externals" property to the parent project's packaging script to manage this dependency, it occurred to me that someone may have found such a property handy before and that it would be awfully nice if the project's developers didn't have to perform their Git checkouts/updates separately. :-)
Unfortunately, my Google searches have yet to turn up such a tool, if it exists. Has anyone heard of such a thing? A Subversion client which, based on the metadata stored in a repository, can perform non-Subversion checkouts? As far as I'm aware, there's generally no such thing as a "post-checkout hook", which I suspect would make this non-trivial to implement without a custom Subversion client, so I'm still hoping such a tool already exists. We primarily use TortoiseSVN on Windows as a client, but suggestions for any tool/platform are welcome.