It seems like diffQced() throws an error if the local copy of the file does not match the repo's. The error message is
Error in review::diffQced("myscript.R") :
Please svn up 'myscript.R' before running comparison
This message is useful if the repo has changed, but the message is misleading if the local copy has been edited. In the latter case a recommendation to revert the file may be helpful.
Version: 3.12.0.9000