"Martin v. Löwis" wrote:
2.7 has an up-to-date backport of the C IO lib (as well as the memoryview object), which means it is better for people wanting to ease transition to 3.x.
But of course, as Martin said, few people will want to support 2.7 only and not 2.6.
Since 2.7 will be closer to 3.2 than 2.6, the result will more likely be: many people will want to support 2.7 and 3.x - which is really what we should be after.
Supporting 2.7 doesn't mean that you have to use the nonlocal keyword (nor does support for 3.2 require that keyword). So I'm not sure how the backport of a feature to 2.x could encourage people to forward-port to 3.x.
True. This particular backport is not all that useful - it is well possible to write code that doesn't need the feature, both in 2.7 and 3.2.
However, if a 3.2 feature is required for code to work out of the box without changes, then I'd regard such a feature as potential backport candidate.
memoryviews are a good example. In 3.x the buffer object is gone and memoryviews are the new replacement for it.
Code written to support both 2.7 and 3.2 would need to have access to these memoryviews in order to avoid having to write special support for buffer objects (for 2.7) and memoryviews (for 3.x).
By backporting memoryviews to 2.7, users no longer have to write support code for buffer objects and that makes things easier for them.