DataflowLinkOptions.PropagateCompletion not working as expected

[rambodghx]

Hi everyone ,
meanwhile I trying to implement some pipelines with IDataFlow , I faced with situation that I'm not sure is that bug or what so I decided to open discussion to find out is there any issue.
var ac = new TransformBlock<int, int>(i => i * 2);
var ac2 = new ActionBlock<int>(i =>{});
ac.LinkTo(ac2,new DataflowLinkOptions{PropagateCompletion = true});
ac.Post(10);
ac.Post(12);
ac2.Complete();

The result is that the ac2 will not propagate completion to ac and await ac.Completion will block.
However the description of this property in docs is saying "whether the linked target will have completion and faulting notification propagated to it automatically"
Is there any misunderstanding about this property?

[svick]

PropagateCompletion works the other way around: you complete ac and then wait for ac2 to complete:

var ac = new TransformBlock<int, int>(i => i * 2);
var ac2 = new ActionBlock<int>(i => { });
ac.LinkTo(ac2, new DataflowLinkOptions { PropagateCompletion = true });
ac.Post(10);
ac.Post(12);
ac.Complete();
await ac2.Completion;

[rambodghx]

I Got it ,
thanks.
Is there any way to propagate upward?

[svick]

Not automatically, but you could always wire that yourself.

Though I'm not sure that makes sense in the dataflow model: the source of the flow of data should know when it's done, not the target/sink.