cache.ErrRequeue advertised itself as a way to requeue failures on a
FIFO, but it suffers the same problems as AddIfNotPresent. If we do
requeue an item at the end, we'll move the informer back in time. If we
requeue at the beginning we'll simply wedge FIFO.
We didn't find examples in the wild, but by removing the error type
those impacted will get a compile error and get to decide what action is
most appropriate for their failure. Most of the time, proceeding to the
next item is best.
Kubernetes-commit: 238c32a1d9b2c72d648193fa8642a53a2884975f
Logically a cache.Queue.AddIfNotPresent means that the informer can move
back in time since an older item is placed after newer items. The
alternative of placing errors at the head of the queue leads to
indefinite memory growth and repeated failures on retry.
Luckily this behavior was behind RetryOnError, which was always set to
false and impossible for normal users to set to true. By removing the
function and setting, impacted users (none found in a github search)
will get a compile failure.
Kubernetes-commit: 8e77ac000131019d5aa49c19aa1f477f6dac4d59
* Add tracker types and tests
* Modify ResourceEventHandler interface's OnAdd member
* Add additional ResourceEventHandlerDetailedFuncs struct
* Fix SharedInformer to let users track HasSynced for their handlers
* Fix in-tree controllers which weren't computing HasSynced correctly
* Deprecate the cache.Pop function
Kubernetes-commit: 8100efc7b3122ad119ee8fa4bbbedef3b90f2e0d
Fixes: kubernetes#90581 (the first part)
When `Close()` is invoked on an empty queue, the control loop inside `Pop()` has a small chance of missing the signal and blocks indefinitely due to a race condition. This PR eliminates the race and allows the control loop inside any blocking `Pop()` to successfully exit after Close() is called.
Kubernetes-commit: d8b90955519d10b99415515f8314dd6d35caae8d
