The looming Python 3(000) monster

Michael DeHaan mdehaan at
Fri Dec 5 14:42:43 UTC 2008

We're just now dealing with Python 2.6, but over on the radar is perhaps 
one of the most incompatible upgrades to the language we've seen in 
Python 3.  I personally haven't tried it yet, but it /aims/ to be 
incompatble, which is perhaps one of the most glaring signs a language 
designer has lost it that I've seen.

This isn't a huge problem to those who are only developing on the latest 
Fedora, per-se (other than getting over the initial hump), but it's 
pretty bad for someone who wants to keep a single codebase across EL 4 
(Python 2.3) and up, which I think a lot of us do.   That gets to be 
darn impossible and we have to double our involvement with code because 
we essentially have to maintain a differently-compatible fork for each 

(NOTE: this requires the viewpoint that not everyone care just about the 
latest Fedora, which might be controversial... but to me, the latest 
Fedora is what I'll run as my dev environment but not everyone can 
upgrade -- and many folks are also running EL and EPEL deserves our full 
support and consideration)

So, what of plans?

Are we looking at also carrying on with packaging 2.N indefinitely when 
we do decide to carry 3, because as I know it, the code changes to make 
something Python 3 compatible will be severe and that's a big item for 
any release, and will probably result in some undiscovered bugs even 
after the initial ports (if applied).

I haven't seen /anything/ regarding a compatibility mode for 
/usr/bin/python, and I'd hate to have to develop a non-core library that 
allows for functions that work the same way on both versions and use 
that instead.  That would be heinous.

Short of porting everything over to Ruby, oCaml, or 
enterprise-Fortran.NET#4000, any ideas on planning for this?


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