Why is it not realistic? Small teams do excellent work. Keep your team small and trusted. Only accept contributions from your team, and people outside your team who are personally vouched for by someone on your team. It's like climbing mountains or sailing or any other type of inherently risky activity--you don't go out with people you don't trust. It's eminently possible, you just don't like the idea of it.
Even pre-AI it was obvious that contributions have to be vetted for a bunch of reasons.
Public repos are read only except for contributors who have been given specific permission, and those permissions are granular e.g. in order of increasing damage potential:
- comment on issue
- create issue
- comment on PR
- create PR
- run CI against PR
- etc.
In other words, shut it down.
Not great for privacy or ad-hoc contributions, but I don't see a way out of the muck without some kind of trust net.
Sounds like you can't accept AI is here to stay
No. You go out the door, and then I clean it up, and you don't get invited back. That's how that works.