Also, it would be very nice to show big red warning in UI that some actions related to particular project are still executed on background.

We do this in a case of forking when the forking action is not finished yet. And this RFE would help because we currently do it an ugly way:

@property
def still_forking(self):
    return bool(Action.query.filter(Action.result == BackendResultEnum("waiting"))
                .filter(Action.action_type == ActionTypeEnum("fork"))
                .filter(Action.new_value == self.full_name).all())

Also, we should IMHO reuse the big red warning from forking and generalize it for this scenario.

That is exactly what I wanted to achieve by this issue, yes.

This issue has been migrated to GitHub: https://github.com/fedora-copr/copr/issues/1017