Python 2.6 and deprecated modules

[Lisandro Dalcin]

Fedora 11 moved to Python 2.6. Now many Python stdlib modules are
deprecated (as part of the transition to Python 3.x series).

/u/dalcinl/Devel/PETSc/petsc-dev/config/BuildSystem/config/compilers.py:7:
DeprecationWarning: the sets module is deprecated
  import sets
/u/dalcinl/Devel/PETSc/petsc-dev/config/PETSc/package.py:7:
DeprecationWarning: the md5 module is deprecated; use hashlib instead
  import md5
/u/dalcinl/Devel/PETSc/petsc-dev/config/BuildSystem/script.py:101:
DeprecationWarning: The popen2 module is deprecated.  Use the
subprocess module.
  import popen2

We could take two approaches to remove these warnings (I bet all you
hate warnings as much as me):

1) Reimplement things using the modern API's, perhaps by using
conditional code depending on the Python version and/or using import
with try/except blocks. In particular, this will require:
a) use the builtin 'set' type (available since Python 2.4)
b) use the 'hashlib' module (available since Python 2.5)
c) moving from using 'peopen2' to 'subprocess' (BTW, available since
Python2.4) will likely remove the need to use 'select', which I
commented some time ago it is not supported (for pipes) in native
Windows Python (yes, some day I'll have some working code with the
native Windows Python).

2) Silent these warnings. I do not think these modules will be ever
removed from 2.x series, and porting the whole BuildSystem beast to
Python 3.0 is not going to be a 10-minutes task anyway.


I personally prefer (1) and volunteer to provide the fixes, even if
that is more work than (2). I would like to know your opinions before
start to work on this.


-- 
Lisandro Dalcín
---------------
Centro Internacional de Métodos Computacionales en Ingeniería (CIMEC)
Instituto de Desarrollo Tecnológico para la Industria Química (INTEC)
Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET)
PTLC - Güemes 3450, (3000) Santa Fe, Argentina
Tel/Fax: +54-(0)342-451.1594