Python 3.3 and .pyo files

Discussion in 'Python' started by Marco, Sep 21, 2012.

  1. Marco

    Marco Guest

    I was trying to import a pyo module in Python 3.3, but Python does not
    find it:

    $ echo "print(__file__)" > foo.py
    $ python3.3 -O -m foo
    /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
    /usr/local/bin/python3.3: No module named foo

    How come? Thanks in advance, Marco

    --
    Marco
    Marco, Sep 21, 2012
    #1
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  2. On Fri, 21 Sep 2012 11:10:07 +0200, Marco wrote:

    > I was trying to import a pyo module in Python 3.3, but Python does not
    > find it:
    >
    > $ echo "print(__file__)" > foo.py
    > $ python3.3 -O -m foo
    > /home/marco/temp/foo.py
    > $ ls
    > foo.py __pycache__
    > $ rm foo.py
    > $ mv __pycache__/foo.cpython-33.pyo foo.pyo


    I cannot duplicate the creation of the foo.cpython-33.pyo file using just
    the -m option. I believe that you created the foo*.pyo file some other
    way. Nevertheless, moving along:


    > $ rm __pycache__ -r
    > $ ls
    > foo.pyo
    > # The following works in Python3.2, but not in 3.3
    > $ python3.3 -O -m foo
    > /usr/local/bin/python3.3: No module named foo



    I can confirm that (1) it works using Python 3.2; (2) it doesn't work
    using Python 3.3; and (3) it does work in Python 3.3 if you don't use the
    -O option.

    I believe that is a bug.

    (Tested using Python 3.2.2 and Python 3.3.0a1)


    --
    Steven
    Steven D'Aprano, Sep 21, 2012
    #2
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  3. Marco

    Marco Guest

    On 09/21/2012 02:55 PM, Steven D'Aprano wrote:

    >> $ ls
    >> >foo.pyo
    >> ># The following works in Python3.2, but not in 3.3
    >> >$ python3.3 -O -m foo
    >> >/usr/local/bin/python3.3: No module named foo

    >
    > I can confirm that (1) it works using Python 3.2; (2) it doesn't work
    > using Python 3.3; and (3) it does work in Python 3.3 if you don't use the
    > -O option.


    It doesn't work with Python 3.3.0rc2 too.

    --
    Marco
    Marco, Sep 21, 2012
    #3
  4. Marco

    Terry Reedy Guest

    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
    Terry Reedy, Sep 22, 2012
    #4
  5. On Fri, 21 Sep 2012 22:46:08 -0400, Terry Reedy wrote:

    > 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.


    Marco is using the standard mechanism for finding, importing, and running
    a module. I don't believe his use of -m should be a problem. It works in
    3.2, and it works with .pyc files in 3.3, I see nothing to suggest it
    shouldn't work with .pyo files in 3.3.


    >> $ 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.


    Yes, and the current directory is on sys.path.

    I would be astonished if python -m could not find a module that happened
    to be in the current directory.


    [...]
    > 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'.


    No it is not redundant. You link specifically to an bug tracker issue
    below where is is clearly decided that if you want to run a .pyo file you
    *must* use the -O switch. (I approve of this decision.)


    >> /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


    Whose words are these following?


    > 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.)"


    I'm not sure if these are your words, or if you are quoting some random
    commenter on the pydev list, or one of the lead developers who might
    actually know what he is talking about.

    As I recall, some time in the recent past Guido came down *hard* against
    the suggestion that support for running sourceless files (.pyc and .pyo)
    should be dropped. Even if I'm misremembering, it is the case that the
    Python 3.3 will find and run a .pyc file, but not a .pyo file. There's a
    new candidate release of 3.3 due out over the next couple of days. If it
    shows the same behaviour, it should be reported as a bug.



    --
    Steven
    Steven D'Aprano, Sep 22, 2012
    #5
  6. On Saturday, 22 September 2012 18:51:01 UTC+5:30, Steven D'Aprano wrote:
    > On Fri, 21 Sep 2012 22:46:08 -0400, Terry Reedy wrote:
    >
    >
    >
    > > 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.

    >
    >
    >
    > Marco is using the standard mechanism for finding, importing, and running
    >
    > a module. I don't believe his use of -m should be a problem. It works in
    >
    > 3.2, and it works with .pyc files in 3.3, I see nothing to suggest it
    >
    > shouldn't work with .pyo files in 3.3.
    >
    >
    >
    >
    >
    > >> $ 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.

    >
    >
    >
    > Yes, and the current directory is on sys.path.
    >
    >
    >
    > I would be astonished if python -m could not find a module that happened
    >
    > to be in the current directory.
    >
    >
    >
    >
    >
    > [...]
    >
    > > 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'.

    >
    >
    >
    > No it is not redundant. You link specifically to an bug tracker issue
    >
    > below where is is clearly decided that if you want to run a .pyo file you
    >
    > *must* use the -O switch. (I approve of this decision.)
    >
    >
    >
    >
    >
    > >> /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

    >
    >
    >
    > Whose words are these following?
    >
    >
    >
    >
    >
    > > 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.)"

    >
    >
    >
    > I'm not sure if these are your words, or if you are quoting some random
    >
    > commenter on the pydev list, or one of the lead developers who might
    >
    > actually know what he is talking about.

    It is Terry J. Reedy's words - see end of http://bugs.python.org/issue12982#msg162814


    > As I recall, some time in the recent past Guido came down *hard* against
    >
    > the suggestion that support for running sourceless files (.pyc and .pyo)
    >
    > should be dropped. Even if I'm misremembering, it is the case that the
    >
    > Python 3.3 will find and run a .pyc file, but not a .pyo file. There's a
    >
    > new candidate release of 3.3 due out over the next couple of days. If it
    >
    > shows the same behaviour, it should be reported as a bug.
    >
    >
    >
    >
    >
    >
    >
    > --
    >
    > Steven
    Ramchandra Apte, Sep 22, 2012
    #6
  7. Marco

    Terry Reedy Guest

    On 9/22/2012 9:21 AM, Steven D'Aprano wrote:
    > On Fri, 21 Sep 2012 22:46:08 -0400, Terry Reedy wrote:
    >
    >> 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.

    >
    > Marco is using the standard mechanism for finding, importing, and running
    > a module. I don't believe his use of -m should be a problem. It works in
    > 3.2, and it works with .pyc files in 3.3, I see nothing to suggest it
    > shouldn't work with .pyo files in 3.3.
    >
    >
    >>> $ 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.

    >
    > Yes, and the current directory is on sys.path.
    >
    > I would be astonished if python -m could not find a module that happened
    > to be in the current directory.
    >
    >
    > [...]
    >> 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'.

    >
    > No it is not redundant. You link specifically to an bug tracker issue
    > below where is is clearly decided that if you want to run a .pyo file you
    > *must* use the -O switch. (I approve of this decision.)
    >
    >
    >>> /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

    >
    > Whose words are these following?
    >
    >
    >> 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.)"

    >
    > I'm not sure if these are your words, or if you are quoting some random
    > commenter on the pydev list, or one of the lead developers who might
    > actually know what he is talking about.


    My words summarizing the discussion on pydev which included at least a
    few lead developers. My initial post was probably 6/12/2012


    --
    Terry Jan Reedy
    Terry Reedy, Sep 22, 2012
    #7
  8. On Fri, 21 Sep 2012 11:10:07 +0200, Marco wrote:

    > I was trying to import a pyo module in Python 3.3, but Python does not
    > find it:

    [...]

    Marco, this bug is apparently now fixed:

    http://bugs.python.org/issue16046

    Please download the latest version of Python 3.3 and try again.

    (Folks, this is why testing and reporting bugs to beta and rc versions is
    so useful. You can often get them fixed quite quickly.)



    --
    Steven
    Steven D'Aprano, Sep 27, 2012
    #8
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