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Re: [Xen-devel] Suggestion: drop python 2.3 support for xen-3.5

To: "Andreas Florath" <xen@xxxxxxxxxxxx>, <xen-devel@xxxxxxxxxxxxxxxxxxx>
Subject: Re: [Xen-devel] Suggestion: drop python 2.3 support for xen-3.5
From: "Jan Beulich" <JBeulich@xxxxxxxxxx>
Date: Wed, 19 Aug 2009 08:01:01 +0100
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I'm definitely against dropping compatibility in a way like this, as it would
mean that I can't use the Xen tools anymore on most of my development/
test systems (SLE10 - and no, I'm not in any way considering installing
newer Python there, as that will make it impossible to get other possible
issues resolved on these systems, as I'll always be asked to first restore
the "stock" state of the machine).


>>> Andreas Florath <xen@xxxxxxxxxxxx> 18.08.09 19:47 >>>

I suggest dropping python 2.3 support for xen-3.5.

Major Reason:
o Functionality / Libraries are missing:
   Example: for a new feature I'm working on a 'working' base64
   encoding and decoding is needed.  The one which comes with
   python 2.3 is not usable.  There is the possibility to copy
   over the 2.4ff implementation into the Xen source tree or
   to implement this functionality (again).  IMHO both ways
   are not sensible.

Additional minor ones:
o Syntactic sugar is missing; e.g.:
   @staticmethod must be expressed by
   'function_name = staticmethod(function_name)'
   The first makes the code more readable.
o 'try: except: finally:' construct is missing in python 2.3
   This can be rewritten using 'try: { try: except: } finally:' but this is
   not really nice.

o Only very old distributions use python versions less than 2.4.
   And IMHO those old versions will never update to xen-3.5.  Typically
   the enterprise distributions (like RHEL or SLES) will stay at the
   same (major) version for each package during the life cycle of the
   distribution's release.
   [For me it looks that only a very few people running old systems with
   xen-3.5. I exchanged some EMails with Isaku Yamahata and
   KUWAMURA Shin'ya (from FUJITSU) - and even those told me that they
   are planing to update in near future or even started to update.]

I read an earlier discussion about this [1], but things are getting more
difficult to use only python 2.3 functionality...

Additionally it makes sense (and IMHO it is important) to have a kind
of roadmap which python version is supported in which release of Xen.
At some point it must be decided, how to deal with python 3. AFAIK
there is a smooth migration path to 3.X from 2.6 only - not
from 2.4 or 2.5

So a support matrix might look like:

Xen | Supported Python Versions
3.4 | 2.3 2.4 2.5 2.6
3.5 | 2.4 2.5 2.6
3.6 | 2.5 2.6
3.7 | 2.6 3.1
4.0 | 3.1 3.2

(Of course starting with Xen 3.6 this is only for illustration.)

Kind regards


[1] http://lists.xensource.com/archives/html/xen-devel/2009-05/msg01331.html 

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