Event Types created for build-in sources are created an deleted in a loop

[matzew]

Describe the bug

1. Apply the main branch, using ko

2. create a broker:

apiVersion: eventing.knative.dev/v1
kind: Broker
metadata:
  name: my-broker

3. Create one of the build-in sources, like PingSource:

apiVersion: sources.knative.dev/v1
kind: PingSource
metadata:
  name: ping-source-broker
spec:
  schedule: "*/1 * * * *"
  data: '{"message": "Hello world!"}'
  sink:
    ref:
      apiVersion: eventing.knative.dev/v1
      kind: Broker
      name: my-broker

4. Watch the eventtypes.eventing.knative.dev resources in the cluster:

➜  ~ k get eventtypes.eventing.knative.dev -A  
NAMESPACE   NAME                                            TYPE                       SOURCE                                                       SCHEMA   REFERENCE NAME   REFERENCE KIND   DESCRIPTION                             READY   REASON
default     b1d49d424cc890bf2eae48d281147469                dev.knative.sources.ping   /apis/v1/namespaces/default/pingsources/ping-source-broker            my-broker        Broker                                                           
default     et-my-broker-28e4c32ad62d0d20c633fd923b016e9c   dev.knative.sources.ping   /apis/v1/namespaces/default/pingsources/ping-source-broker            my-broker        Broker           Event Type auto-created by controller   True    
➜  ~ 
➜  ~ 
➜  ~ k get eventtypes.eventing.knative.dev -A 
NAMESPACE   NAME                                            TYPE                       SOURCE                                                       SCHEMA   REFERENCE NAME   REFERENCE KIND   DESCRIPTION                             READY   REASON
default     et-my-broker-28e4c32ad62d0d20c633fd923b016e9c   dev.knative.sources.ping   /apis/v1/namespaces/default/pingsources/ping-source-broker            my-broker        Broker           Event Type auto-created by controller   True    

Summary: You notice that EventType resources are created and deleted. In a loop.

Expected behavior

No looping or conflicting behavior.

To Reproduce
Steps to reproduce the behavior.

Knative release version

With release-1.11+

Additional context
Add any other context about the problem here such as proposed priority

[Cali0707]

/assign

[Cali0707]

@matzew if we already have an existing ET from the pingsource, should the broker autocreate the ET as well or should it just not create anything?

[matzew]

there is some mismatch, w/ that.
But for the build-in sources we do have our duck reconciler create event types, on workloads

E.g. try w/ knative 1.10 release, and just do the above sample