As a distribution maintainer of several Python modules, I've run into this bug twice in the past week.  In each case, the python file in question had a SyntaxError and failed to compile, but the error just scrolled past in a large log and was missed because no failure occurred until we attempted to package the result, and the .pyc files were missing.

While we managed to track the problem down fairly easily in both cases, if we only had folks working on the problem that didn't have lots of experience in tracking down build issues, this could have wasted a lot of otherwise valuable engineering time.

I understand the desire to be able to package files that fail to compile, but having that be the default seems to me like it fails basic expectations, even given how long this bug has been around.  I can't imagine that the number of deliberately-broken python files is particularly large compared to the number of python files that might get broken accidentally (or files that are "broken" for one version of python but not another) and so being required to maintain an exception list doesn't seem unreasonable.  (Neither does some amount of transition period -- one or two minor releases of Python? -- between the introduction of the mechanism and the change of the default.)

Would people be interested in a patch to that effect?