Hook scripts should never attempt to modify the contents of your transaction. You could:
- Break the commit process entirely
- Find yourself in a race condition
- Slow down everyone while they wait for the hook to complete
- Break the code that the user is attempting to commit (code that compiled for the developer suddenly doesn't compile when checked out)
- (Best-case scenario) what the user thinks they just committed isn't what actually went into the repository and they are forced to run
svn update
after every commit just to see what's really in the repository.
It's unclear what you're trying to achieve here with this replacement. If svn:keywords
isn't providing the information or format that you need, don't use it and instead use a different method to achieve your desired state.