[Python-Dev] Python 3.4: What to do about the Derby patches

[Ronald Oussoren]

On 17 Feb 2014, at 00:43, Nick Coghlan <ncoghlan at gmail.com> wrote:

> 
> On 17 Feb 2014 08:36, "Greg Ewing" <greg.ewing at canterbury.ac.nz> wrote:
> >
> > Larry Hastings wrote:
> >
> >> 3) We hold off on merging the rest of the Derby patches until after 3.4.0 final ships, then we merge them into the 3.4 maintenance branch so they go into 3.4.1.
> >
> >
> > But wouldn't that be introducing a new feature into a
> > maintenance release? (I.e. some functions that didn't
> > have introspectable signatures before would gain them.)
> 
> From a compatibility point of view, 3.4.0 will already force introspection users and tool developers to cope with the fact that some, but not all, builtin and extension types provide valid signature data. Additional clinic conversions that don't alter semantics then just move additional callables into the "supports programmatic introspection" category.
> 
> It's certainly in a grey area, but "What's in the best interest of end users?" pushes me in the direction of counting clinic conversions that don't change semantics as bug fixes - they get improved introspection support sooner, and it shouldn't make life any harder for tool developers because all of the adjustments for 3.4 will be to the associated functional changes in the inspect module.
> 
> The key thing is to make sure to postpone any changes that impact *semantics* (like adding keyword argument support).

But there is a semantic change: some functions without a signature in 3.4.0 would have a signature in 3.4.1. That’s unlikely to affect user code much because AFAIK signatures aren’t used a lot yet, but it is a semantic change non the less :-)

Ronald