FilterFunc in the informer is not working on the first run of reconciler

[danyinggu]

/kind bug

Expected Behavior

The informer should always successfully filter objects based on filterFunc defined the informer

Actual Behavior

In the first run of the reconcile, it lists all objects and objects are not filtered by filterFunc in the informer

Steps to Reproduce the Problem

1. Given a controller with an informer that has a filterFunc
2. Deploy the controller
3. In the first run of the reconciler, it reconciles all the objects but not only the objects should pass the filterFunc

Additional Info

We did some investigation, in the genreconciler: https://github.com/google/knative-gcp/blob/3707bd3ca3d010532b334201dc7da6c9bc382959/pkg/client/injection/reconciler/broker/v1beta1/broker/controller.go#L73-L81
When a controller starts, a new leader is promoted with a listAll operation and there is no informer resync.

[danyinggu]

@mattmoor @n3wscott @grantr

[mattmoor]

Yup, there's no filter passed to genreconciler currently, but you could plumb one through in the controller options.

[grantr]

@mattmoor can you point to an example of plumbing through? Looks like the code directly enqueues every object in the lister, skipping any informer FilterFunc.

[mattmoor]

By "plumbing through" I mean adding a field and calling it from that logic in genreconciler itself, there is no field today.

[github-actions]

This issue is stale because it has been open for 90 days with no
activity. It will automatically close after 30 more days of
inactivity. Reopen the issue with /reopen. Mark the issue as
fresh by adding the comment /remove-lifecycle stale.

[mattmoor]

/lifecycle frozen