severity 1061410 wishlist thanks This doesn't seem like a bug in python-trio to me. It's simply using select.epoll(). If that's being monkey patched by gevent in a way that breaks things then that seems like either a gevent problem or a fundamental incompatibility in trying to use Trio at the same time as gevent.
https://github.com/python-trio/trio/pull/2928 might be a workaround we could take if upstream takes it, but nevertheless what Trio is currently doing is certainly not wrong, and so "grave" seems inappropriate.