They can use git. They can use mailing lists. They can use carrier pigeons to exchange pull requests. That's not what the concern is about.
If the OSS project says that all collaboration work has to happen on their Github projects, and Github's forced to block China - then Chinese devs would no longer able to collaborate.
They would need someone outside China to be willing to take their pull request/log an issue/etc.
Sure, but that's not the issue I'm addressing here. If a project insists on github no matter what, and github gets blocked, and the project keeps insisting on github, obviously that's a problem. Nobody is denying that. It's obvious.
My point is to underscore the point of the ancestor of this thread: that you (the project) don't need github. You can use all the strength of git without github.
It will be possible to create a bridge bot, between e.g. GitLab and GitHub, through their API to synchronize PRs, issues, commits, etc automatically. So this particular problem is solvable.
They can use git. They can use mailing lists. They can use carrier pigeons to exchange pull requests. That's not what the concern is about.
If the OSS project says that all collaboration work has to happen on their Github projects, and Github's forced to block China - then Chinese devs would no longer able to collaborate.
They would need someone outside China to be willing to take their pull request/log an issue/etc.