The real problem with Python 3 - no business case for conversion

[Terry Reedy]

On 7/7/2010 10:49 PM, Ben Finney wrote:

> Yes, that's what I meant. Python 3 is deliberately under no obligation
> to support code that works in Python 2. If something needs fixing, and
> that fix would involve breaking Python 2 code, then that's not a
> consideration any more.

Code that works in 3.1 *is* 3.1 code. Leaving aside bug fixes and 
additions that makes code that once raised an exception do something 
instead, I do not know that 3.1 broke and 3.0 code and I do not know of 
any deprecations in 3.1 that will become removals in 3.2.

> The predictable result is that Python 3 will continue to gain
> backward-incompatible changes in future.

For the core syntax, not too likely. In any case, the usually 3 version 
pending-deprecation, deprecation, removal process would apply. Some of 
the library modules that do not work well for 3.1 will see more changes.

>> On the other hand, the door appears closed for Python 3 adding more
>> stuff that breaks Python 2 code.
>
> What gives you that idea? Can you reference a specific statement from
> the PYthon developers that says that?

3.0 was stated to be a special case. I will let you look.

-- 
Terry Jan Reedy