[Python-Dev] Re: Request to postpone some Python 3.9 incompatible changes to Python 3.10

On 2020-01-23 07:20, Victor Stinner wrote:

Python 3.9 introduces many small incompatible changes which broke tons

There's a well-known and established way of signaling breaking changes in software platforms—it is to increment the major version number. Rather than debating the merits of breaking code on 3.9 or 3.10, wouldn't it make more sense to do it in a Python 4.0 instead? Well, either of these strategies sound logical to me: - Python 4.0 with removal of all of the Python 3-era deprecations - Continuing Python 3.1X with no breaks In other words, we should keep compatibility, or not. In any case, from the looks of it these will be tiny breaks compared to the Unicode transition. Cheers, -Mike