On 07/23/2013 01:22 PM, Chris Jones wrote:
>
> In DataFormats/Provenance/interface/Parentage.h:
>
> >      void initializeTransients() {transient_.reset();}
> > -
> >      struct Transients {
>
> I assumed this stayed to avoid backwards compatibility problems?
>
> —
> Reply to this email directly or view it on GitHub 
> <https://github.com/cms-sw/cmssw/pull/167/files#r5352521>.
>

1) Possible backward compatibility problems was one reason.

Other reasons:

2) Removing it forces tricky changes in classes_def.xml which are 
non-trivial to get right, if they work at all.

3) Future proofing against a subsequent addition of new transient data 
members.

4) Standardization:  Keeping it makes it like other registries.

Bill