CancelableOperation should not cause deadlocks about async HOT 3 CLOSED

The API is intended to have operation.value never complete when the operation is canceled.

Our choices are either to have value never complete, or to complete as an error with something liked a CanceledException. Changing it to complete with an error will be very breaking and probably isn't the behavior most users would want because the vast majority of use cases would need to suppress that error.

The valueOrCancellation() API is the correct API to use if you want to avoid the Future that may never complete.

from async.

What is the lifecycle of thens on such never completed futures? Can they be GC'ed at some point or do they live forever waiting that the future completes?

from async.

What is the lifecycle of thens on such never completed futures? Can they be GC'ed at some point or do they live forever waiting that the future completes?

The callback can be collected as long as the future instance can be collected. That is to say - a future that never completes is not necessarily going to cause any memory leak. If you are concerned about a particular use of a future leaking you can use devtools to investigate the heap. https://flutter.dev/docs/development/tools/devtools/memory

from async.