bytecode non-backcompatibility

[Robert Kern]

Maurice LING wrote:
> Hi,
> 
> I've been using Python for about 2 years now, for my honours project and 
> now my postgrad project. I must say that I am loving it more and more 
> now. From my knowledge, Python bytecodes are not back-compatible. I must 
> say that my technical background isn't strong enough but is there any 
> good reason for not being back-compatible in bytecodes?
 >
> My problem is not about pure python modules or libraries but the problem 
> is with 3rd party libraries with C bindings (not python pure).

Then this has nothing to do with bytecode incompatibility. Only 
pure-Python modules get compiled to bytecode. You mean binary 
compatibility of the C API.

If you're going to have significant improvements in the core 
interpreter, you have to break binary compatibility from time to time.

> It means 
> that with every upgrade of python, I have to reinstall all my 3rd party 
> libraries which can be quite a bit of work...
> 
> I do hope this problem will be sorted out some day.

This problem is mitigated somewhat by the fact that the devs keep binary 
compatibility within a major revision series (e.g. 2.3.0, 2.3.1, 2.3.2, 
...).

-- 
Robert Kern
rkern at ucsd.edu

"In the fields of hell where the grass grows high
  Are the graves of dreams allowed to die."
   -- Richard Harter