ERL-302: rpc:yield() does not work from another pid

[OTP-Maintainer]

Original reporter: jimdigriz
Affected version: OTP-19.1
Fixed in version: OTP-19.2
Component: Not Specified
Migrated from: https://bugs.erlang.org/browse/ERL-302

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Whilst getting to grips with erlang (and having fun!) I ran into a problem in which a call I make to rpc:async_call() then never yields.

I am guessing this could be caused by yield() under-the-hood using mailbox messaging and of course so when I try to yield from another pid it never sees that message.

This I am OK with, if it is not considered a bug, but then most definitely something that should be mentioned in the docs:

http://erlang.org/doc/man/rpc.html#nb_yield-2

Maybe have yield()/nb_yield() complain about it being a invalid key as someone like me tries to foolishly yield from a different pid too?

Anyway, attached is a small test module showing this behaviour, tested on the esl-erlang Debian package from Errlang Solutions, version 1:19.1.5.

[OTP-Maintainer]

vladdu said:

I wouldn't call this a bug, but it is possible to implement it differently so that yield can be called from any process. The question is whether this would be desirable.

The documentation for `async_call` and `*yield` should mention that they all need to be called from the same process. Could you please write a PR for that?

[OTP-Maintainer]

jimdigriz said:

https://github.com/erlang/otp/pull/1252