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2 different versions of python compiling files.

P: n/a
I am trying to upgrade from python 2.3 to 2.4 but not all machines can
be upgraded. Can you guys tell me if this scenario is possible.

1. Any machine that uses .py files that use libraries that require 2.4
will have 2.4 on it.
2. rest of the machines will have 2.3

now there is a shared drive. lets say i write a new library called
testlib.py and put it on the shared drive .. when a script uses it
from a 2.4 based machine, it will generate a testlib.pyc and leave it
on the shared drive. going forward that .pyc is used until the
original lib is changed. now lets say a 2.3 based machine is trying to
use that lib. it will try to use that pyc file which was compiled by
py2.4. will it work or crash ?

not sure if i did a good job on explaining my scenario.
Jun 27 '08 #1
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4 Replies


P: n/a
TkNeo wrote:
I am trying to upgrade from python 2.3 to 2.4 but not all machines can
be upgraded. Can you guys tell me if this scenario is possible.

1. Any machine that uses .py files that use libraries that require 2.4
will have 2.4 on it.
2. rest of the machines will have 2.3

now there is a shared drive. lets say i write a new library called
testlib.py and put it on the shared drive .. when a script uses it
from a 2.4 based machine, it will generate a testlib.pyc and leave it
on the shared drive. going forward that .pyc is used until the
original lib is changed. now lets say a 2.3 based machine is trying to
use that lib. it will try to use that pyc file which was compiled by
py2.4. will it work or crash ?
It should work, as long as the original .py file is still there. Each Python
version will check for a .pyc file *corresponding to that version* (e.g. Python
2.4 will look for a .pyc file compiled with 2.4), and create one if it doesn't
exist, overwriting any existing .pyc file in the process.

If the original .py file is *not* there, it will most likely not work. If you
try to import a .pyc file with the wrong version number, you get something like
this:
>>import foo
Traceback (most recent call last):
File "<stdin>", line 1, in ?
ImportError: Bad magic number in foo.pyc

I'm not sure what would happen if multiple Pythons try to write a .pyc file at
the same time, though...

--
Hans Nowak (zephyrfalcon at gmail dot org)
http://4.flowsnake.org/
Jun 27 '08 #2

P: n/a
On May 22, 2:44 pm, Hans Nowak <zephyrfalcon!NO_SP...@gmail.com>
wrote:
TkNeo wrote:
I am trying to upgrade from python 2.3 to 2.4 but not all machines can
be upgraded. Can you guys tell me if this scenario is possible.
1. Any machine that uses .py files that use libraries that require 2.4
will have 2.4 on it.
2. rest of the machines will have 2.3
now there is a shared drive. lets say i write a new library called
testlib.py and put it on the shared drive .. when a script uses it
from a 2.4 based machine, it will generate a testlib.pyc and leave it
on the shared drive. going forward that .pyc is used until the
original lib is changed. now lets say a 2.3 based machine is trying to
use that lib. it will try to use that pyc file which was compiled by
py2.4. will it work or crash ?

It should work, as long as the original .py file is still there. Each Python
version will check for a .pyc file *corresponding to that version* (e.g. Python
2.4 will look for a .pyc file compiled with 2.4), and create one if it doesn't
exist, overwriting any existing .pyc file in the process.

If the original .py file is *not* there, it will most likely not work. If you
try to import a .pyc file with the wrong version number, you get something like
this:
>>import foo
Traceback (most recent call last):
File "<stdin>", line 1, in ?
ImportError: Bad magic number in foo.pyc

I'm not sure what would happen if multiple Pythons try to write a .pyc file at
the same time, though...

--
Hans Nowak (zephyrfalcon at gmail dot org)http://4.flowsnake.org/
The original .py will always be there but you know what, multiple
python versions from different computers do access that one library at
the same time.

Anyone know a possible solution ?
Jun 27 '08 #3

P: n/a
On May 22, 3:56 pm, TkNeo <tarun....@gmail.comwrote:
On May 22, 2:44 pm, Hans Nowak <zephyrfalcon!NO_SP...@gmail.com>
wrote:
TkNeo wrote:
I am trying to upgrade from python 2.3 to 2.4 but not all machines can
be upgraded. Can you guys tell me if this scenario is possible.
1. Any machine that uses .py files that use libraries that require 2.4
will have 2.4 on it.
2. rest of the machines will have 2.3
now there is a shared drive. lets say i write a new library called
testlib.py and put it on the shared drive .. when a script uses it
from a 2.4 based machine, it will generate a testlib.pyc and leave it
on the shared drive. going forward that .pyc is used until the
original lib is changed. now lets say a 2.3 based machine is trying to
use that lib. it will try to use that pyc file which was compiled by
py2.4. will it work or crash ?
It should work, as long as the original .py file is still there. Each Python
version will check for a .pyc file *corresponding to that version* (e.g. Python
2.4 will look for a .pyc file compiled with 2.4), and create one if it doesn't
exist, overwriting any existing .pyc file in the process.
If the original .py file is *not* there, it will most likely not work. If you
try to import a .pyc file with the wrong version number, you get something like
this:
>>import foo
Traceback (most recent call last):
File "<stdin>", line 1, in ?
ImportError: Bad magic number in foo.pyc
I'm not sure what would happen if multiple Pythons try to write a .pyc file at
the same time, though...
--
Hans Nowak (zephyrfalcon at gmail dot org)http://4.flowsnake.org/

The original .py will always be there but you know what, multiple
python versions from different computers do access that one library at
the same time.

Anyone know a possible solution ?
What error message are you getting?
Jun 27 '08 #4

P: n/a
The original .py will always be there but you know what, multiple python
versions from different computers do access that one library at the same
time.

Anyone know a possible solution ?
What about subversion or mercurial and separate copies of your library
for each Python version?

-- Ivan
Jun 27 '08 #5

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