This is a nice conservation. :-)
I tried to log in with one of my bots interactively via web browser, and after login I got a screen stating my password was invalid because it was shorter than 8 characters, and I was obliged to change it. Afterwords I could log in. This is a case that is not handled by login.py at all. I don't dare to change the password of my main bot account because it is fortunately still logged in to compat, and I don't want to risk it.
Furthermore, after login I got these warnings from API:
WARNING: API warning (main): Subscribe to the mediawiki-api-announce mailing list at <
https://lists.wikimedia.org/mailman/listinfo/mediawiki-api-announce> for notice of API deprecations and breaking changes. Use [[Special:ApiFeatureUsage]] to see usage of deprecated features by your application.
WARNING: API warning (login): Main-account login via "action=login" is deprecated and may stop working without warning. To continue login with "action=login", see [[Special:BotPasswords]]. To safely continue using main-account login, see "action=clientlogin".
Logged in on wikipedia:hu as BinBott.