Language change and code breaks

[Peter Hansen]

Bjorn Pettersen wrote:
> 
> > From: Peter Hansen [mailto:peter at engcorp.com]
> > Nevertheless, I want to make the clear point (if I haven't already)
> > that I'm not suggesting screwing every such programmer... just
> > those who are actively using code which would be broken, who will
> > not take the time (however small we might make it) to modify the
> > source, and yet who "must" have their code work under the new Python.
> >
> > Are there really any people like that?  Enough to make it
> > a key factor?  I'm not sure I can even think of any realistic
> > cases where anyone like that exists (he said, trolling for
> > someone to point out an obvious example or two).
> 
> Well, I for one wrote several thousands of lines of Python code in my
> last job, and I obviously have no influence on when they're going to
> upgrade to a newer version of Python. You can probably safely assume
> that they're not going to put a programmer on fixing programs that are
> running without any problems. More likely they would upgrade Python,
> realize that "a bunch" of Python scripts stopped working, and either
> roll back the Python upgrade, rewrite them in Perl/Java, or find someone
> with enough Python skills to fix the problems. Neither solution would be
> good PR for Python...

I agree it wouldn't be good PR for Python, but presumably neither
is having division which doesn't behave as newcomers expect.
We're trying to choose the lesser of two evils.

Anyway, if your previous employer upgrades Python for no good
reason and without checking the Change History where they will
see all the warnings in BIG PRINT about how existing code might
break and that they should run "divscan.py" to see if their code
is safe or not, how can we protect them against themselves?

I'm trying to point out that this kind of hypothetical example,
where some group might upgrade (but not be aware of this issue
even after lengthy publicity during the transition period) 
even though they will not actively maintain their code, is 
not likely, or not worth worrying about for long.

And that's where the contingency plans come into play: we've 
provided adequate notice, tools, etc., and yet somebody chose 
to ignore us and got punished.  Big deal.

-Peter Hansen