[Python-Dev] #12982: Should -O be required to *read* .pyo files?

[R. David Murray]

On Wed, 13 Jun 2012 11:20:24 -0700, Toshio Kuratomi <a.badger at gmail.com> wrote:
> On Wed, Jun 13, 2012 at 01:58:10PM -0400, R. David Murray wrote:
> > 
> > OK, but you didn't answer the question :).  If I understand correctly,
> > everything you said applies to *writing* the bytecode, not reading it.
> > 
> > So, is there any reason to not use the .pyo file (if that's all that is
> > around) when -O is not specified?
> > 
> > The only technical reason I can see why -O should be required for a .pyo
> > file to be used (*if* it is the only thing around) is if it won't *run*
> > without the -O switch.  Is there any expectation that that will ever be
> > the case?
> > 
> Yes.  For instance, if I create a .pyo with -OO it wouldn't have docstrings.
> Another piece of code can legally import that and try to use the docstring
> for something.  This would fail if only the .pyo was present.

Yes, but that's not what I'm talking about.  I would treat code that
depends on the presence of docstrings and doesn't have a fallback for
dealing with there absence as buggy code, since anyone might decide
to run that code with -OO, and the code would fail in that case too.

I'm talking about a case where the code runs correctly with -O (or -OO),
but fails if the code from the .pyo is loaded and python is run
*without* -O (or -OO).

> Of course, it would also fail under the present behaviour since no .py or
> .pyc was present to be imported.  The error that's displayed might be
> clearer if we fail when attempting to read a .py/.pyc rather than failing
> when the docstring is found to be missing, though.

Well, right now if there is only a .pyo file and you run python without
-O, you get an import error.  The question is, is that the way we really
want it to work?

--David