> I may be mistaken, but I do not think the change introduced a regression.

I'm talking about this:
https://bugs.python.org/issue39991#msg364435

I don't want to blame anyone. My intent here is to get more eyes on the changes that I merged in bpo-39991 to make sure that I didn't break any existing cases, and that I covered all cases.


> While it is true that this case would not have appeared if there was
still a count of the field-separators an IPv6 address with 5 ':' and 17
characters would have failed as well.

Right, I pushed a second fix to also handle this case: commit ebf6bb9f5ef032d1646b418ebbb645ea0b217da6.


> IMHO - while issue39991 is resolved - I am not -yet- convinced that the "root cause" has been identified and properly coded

If you still see cases which are not handled properly with commit ebf6bb9f5ef032d1646b418ebbb645ea0b217da6, feel free to reopen bpo-39991.