It seems to me that the API only supports execution of the 'svn' command and it's various parameters and switches. The problem is that in subversion, a different executable command is used to retrieve a proper detailed version number, that being 'svnversion'. Using this command, I can tell if I have a mixed version, a modified version, etc. For example:
[jim@localhost sb_rc1 993]$ svn info | grep Revision
[jim@localhost sb_rc1 994]$ svnversion
[jim@localhost sb_rc1 994]$
Guess what? 'svn info' is lying to me here. My local copy is modified from the original 51159 which is why 'svnversion' reports the version number with an M attached to it. What if I'm experimenting with a branch that contains a mixed version? 'svnversion' can handle this. 'svn info' cannot. Worse, as shown above, it will provide misleading and potentially disastrous information if, for example, I'm basing a release off of the bad info.