[Python-Dev] Policy for making changes to the AST

[Guido van Rossum]

On Sun, Apr 3, 2011 at 6:43 PM, Nick Coghlan <ncoghlan at gmail.com> wrote:
> On Mon, Apr 4, 2011 at 5:11 AM, Guido van Rossum <guido at python.org> wrote:
>> In the mean time, until we hear differently, I'm also in favor of #1
>> (do nothing). I would (perhaps redundantly) say that such changes
>> should only go into new major releases (i.e. 3.3 right now), not
>> backported into bugfix releases (e.g. 3.2.1). AFAIK the AST is
>> CPython-specific so should be treated with the same attitude as
>> changes to the bytecode. That means, do it conservatively, since there
>> *are* people who like to write tools that manipulate or analyze this,
>> and while they know they're doing something CPython and
>> version-specific, they should not be broken by bugfix releases, since
>> the people who *use* their code probably have no idea of the deep
>> magic they're depending on.
>
> Perhaps we should add a warning to the ast module docs similar to the
> one we have for the dis module, and use it to explicitly remind people
> to check ast.__version__ before proceeding with AST manipulation?

Sure, but do we have any indication that the warnings for dis make a difference?

-- 
--Guido van Rossum (python.org/~guido)