[Python-Dev] Cygwin Python 2.1c1 test_threadedtempfile problem

[Tim Peters]

[Michael Hudson]
> Maybe modules should be removed from sys.modules when they fail to be
> imported due to an exception?

[Guido]
> This has been suggested before, but *in general* this is not a good
> idea.  For example, you want to debug the remains of the failed
> module.

Ya, I've heard you say something like that before, but haven't understood
what it meant.  That is, I've never had, or been able to picture, a case
where having a module object in an incomplete and unknown state is actually
of use.  OTOH, I've certainly burned my share of time recovering from that
importing a broken module only fails the first time.  It's like Python only
raised an exception the first time somebody tried to open a particular
non-existent file for reading, but the second time it returned a file object
that may or may not fail in use, and may or may not work correctly when it
doesn't fail, depending on what you do with it.

> However, the test suite can easily guard against this, e.g. by
> inserting "import thread" before "import threading" whereever it
> occurs.

So how come a failed attempt to import thread doesn't leave a bogus module
object in sys.modules["thread"] too <0.9 wink>?  This is obscure stuff.  Is
"debugging the remains" of sufficient use to make up for the conceptual
complications?