Capistrano错误：未定义的方法`yet_invoked'for []>：Rake :: Task

I've spent way too much time debugging this, and I have no idea what's going on. "cap production deploy" worked fine this morning, and now it just throws an error. Google has not been of much help so far, surprisingly. Nothing has changed in the code base that I know of:I've spent way too much time debugging this, an