Rather than saying we shouldn't make this assumption (which I assume has already been made in places, and will likely be made again), can we fix the problem? There's a `TODO` already suggesting running the callback in a separate execution environment. We could also synchronize with thread setting the future to true.
I'd rather discuss and fix the problem, than try to enforce avoiding this case. Thoughts? — *Joris Van Remoortere* Mesosphere On Tue, Mar 29, 2016 at 2:50 AM, Jie Yu <yujie....@gmail.com> wrote: > Hi, > > While digging a bug reported in, I realized an assumption we shouldn't make > in our code. > https://issues.apache.org/jira/browse/MESOS-5023 > > Say you have the following code: > > void some_func() > { > future > .onAny(callback_A) > .onAny(callback_B); > } > > Question: will callback_A already be executed before callback_B? > > The answer is NO. We should never assume that. Under the following > interleaving, callback_B can be invoked first: > > Thread-1 Thread-2 > > onAny(callback_A) { > onAnyCallbacks.push_back(callback_A); > } > set() { > lock() > if (state == > PENDING) { > state = READY; > result = true; > } > unlock(); > > onAny(callback_B) { > lock() > if (state != PENDING) { > run = true > } > unlock() > > if (run) { > callback_B() > } > > if (result) { > > internal::run(data->onAnyCallbacks, > *this); > } > > - Jie >
