Python style: exceptions vs. sys.exit()

[Terry Reedy]

Drake wrote:
> I have a general question of Python style, or perhaps just good
> programming practice.
> 
> My group is developing a medium-sized library of general-purpose
> Python functions, some of which do I/O. Therefore it is possible for
> many of the library functions to raise IOError Exceptions. The
> question is: should the library function be able to just dump to
> sys.exit() with a message about the error (like "couldn't open this
> file"),

No

 > or should the exception propagate to the calling program which
> handles the issue?

Yes -- with an informative error message.

If the caller ignores the exception, the program will exit with a full 
stack trace anyway.