fetchInput needs to give some sort of error filename on failure(?).
fetchInput needs to give some sort of error filename on failure(?). Currently we get annoying behavior that if fetchInput fails, some random debug message or CPN output gets interpreted as the returned local path from its output...
This isn't a problem in the C++ or Python usage; but in the shell script usage,
we read the translated path on stdout, but other things (like CPN lock/unlock) say things on stdout, too.
So if we fail, some other random string comes back to the shell script, and it thinks it is the local path
we're supposed to use for the file, which causes confusing errors later.