support of symlinks in SVN on Windows

Question

Any thoughts regarding supporting symlinks in SVN on Windows? Windows has supported symlinks since Vista:
http://msdn.microsoft.com/en-us/library/windows/desktop/aa365680(v=vs.85).aspx

Supporting cross-platform symlinks where possible will ease some compatibility pain for cross-platform development.

Answer 1

Probably the biggest issue here is that by default creating symbolic links requires administrator access on Windows. Users can be granted the permission without being an administrator. However, lacking the functionality for all users (as is the case on unix) makes it possible to cause problems for users on
Windows without the permission.

http://superuser.com/questions/124679/how-do-i-create-a-link-in-windows-7-home-premium-as-a-regular-user

I think nobody has put the effort into figuring out the appropriate way of dealing with this. The obvious thing to do would be to fall back to the current behavior if the permission isn't available. My concern would be that this would be confusing when the feature works for some users and doesn't for other users based on something as obscure as Windows a user permission.

Comments

Subversion could fall back to using junctions if the link target is a directory or hardlinks if it is a file. Junctions don't support links to things like network shares, though, but it's better than nothing and will surely cover 99% of the use cases. Hardlinks have the same caveat of course and suffer form recreation of files, like when a file gets reverted the former created hardlink to it will get invalid. But in theory as Subversion should normally be the on doing the revert it could beforehand get all hardlinks to the file and recreate those after the revert. Getting all hardlinks to a file is fast operation since Vista.

Of course it sucks that symlinks are restricted on Windows, opposed to junctions and hardlinks, especially that Windows itself doesn't use symlinks that much at all, but relies heavily on hard links instead.