[Python-Dev] draft pep: backwards compatibility

[glyph at divmod.com]

On 11:11 am, solipsis at pitrou.net wrote:
><glyph <at> divmod.com> writes:
>>
>>This is a false dichotomy; for core developers, the list needs to be
>>exhaustive.  Everything that can change needs to be described as 
>>either
>>compatible or incompatible.
>
>How do you enumerate "everything that can change"? It does not look 
>like a
>finite set to me (but perhaps I'm wrong); and certainly not like a set 
>of a size
>reasonable enough to be enumerated in a human-readable way :)

Sorry.  You're right.  To be clear, I mean, "everything that can change" 
as classified by some arbitrary classification system yet to be defined 
:-).

For example, the number of different programmatic entities in Python is 
pretty small: you've got classes, methods, modules, and constants.  The 
ways you can change them is also not too huge: you can add to them, 
remove them, or rename them.  I realize that given Python's flexibility 
when loading code, any system of such classification is going to have 
edge cases, but I doubt those are going to matter that much.