Python 3.3 and .pyo files

[Terry Reedy]

On 9/21/2012 5:10 AM, Marco wrote:
> I was trying to import a pyo module in Python 3.3, but Python does not
> find it:

You appear to be trying to *run*, not *import* a .pyo module.

> $ echo "print(__file__)" > foo.py
> $ python3.3 -O -m foo

Since foo.py is in the current directory, I am not sure why you use '-m 
foo' instead of 'foo.py'. -m is for running a module somewhere on sys.path.


> /home/marco/temp/foo.py
> $ ls
> foo.py  __pycache__
> $ rm foo.py
> $ mv __pycache__/foo.cpython-33.pyo foo.pyo
> $ rm __pycache__ -r
> $ ls
> foo.pyo
> # The following works in Python3.2, but not in 3.3
> $ python3.3 -O -m foo

I would try just 'foo.pyo' in case the -m part is the problem.
Also, the -O is sort of redundant, or perhaps interfering, since its 
usual effect to to say 'get and put, from and to the cache, .pyo instead 
of .pyc'.

> /usr/local/bin/python3.3: No module named foo
>
> How come? Thanks in advance, Marco

You might read some of http://bugs.python.org/issue12982

in particular, from http://bugs.python.org/issue12982#msg162814

"Indeed, since I posted last night, the pydev discussion has moved to 
the question of whether -O, __debug__, and .pyo as now defined are worth 
the nuisance they cause or whether some or all should be deprecated. 
(Docstring stripping for saving space could then be a separate tool.)
---
Python interpreters exist to run Python code. The existence, 
persistence, and other details of compilation caches are 
version-dependent implementation details. Being able to execute from 
such caches without source present is also an implementation detail, and 
for CPython, it gets secondary support at best. (This is a compromise 
between full support and no support.)"

-- 
Terry Jan Reedy