Auto forwarding cmd_result get_accepted bug about nuraft

[greensky00]

@FletcherJ1
You're right, thanks for letting us know.

Would you mind submitting PR for this fix? Thanks.

[FletcherJ1]

Yeah of course. No worries.

[FletcherJ1]

Also, another problem I've just noticed is that the rpc send call is async leading to the result being returned before it is populated by the callback. This is fine if the return method is set to async but when using blocking it will immediately return when using auto-forwarding resulting in a false result. I'm not sure how to change rpc send to be blocking in this case.

[FletcherJ1]

I've made a patch for this but I'm not sure if it is the best way. I've added a method into cmd_result called wait() which uses the internal condition variable cv_. Then, when the callback is called from the rpc send method it calls set_result which notifies any waiting threads to continue. The wait/notify functionality is already present for set_result() and get() but I can't use get() due to the way append_entries() creates the cmd_result variable making get() immediately return because it thinks there is already a result.

Hope that makes sense. I can submit a separate PR for this or combine it into #132.

[greensky00]

Thanks @FletcherJ1 ! I just merged your current PR.

Regarding get() and wait() function, can you please elaborate more? I believed get() will wait until set_result() is invoked, as has_result_ is initialized to false. Once you submit your new PR first, and we can discuss it on the PR directly.

[FletcherJ1]

Okay, I'll submit a PR and discuss there. I'll close this since it's fixed.