Hey Antoine, Christian, Senthil!

I have invested quite a bit more time to double-check my responses to the questions asked so far, clarified where appropriate, and updated the pull request on GitHub after manually resolving the merge conflicts that accumulated over time.

I would very much appreciate to get another round of feedback. Can we somehow expedite this? I am available for pushing this further, so that maybe we can still land this in 3.7 after we missed 3.6 last year.

Based on the diff this change _appears_ to be risky but I would like to stress again that I approached this issue pretty conservatively. I tried to make this a conceptually backwards-compatible change by keeping the old code path intact (the old tests pass, too, but this is not the best criterion here).

Cheers and thanks!

Jan-Philip