[lbarrosby]

Related to #5374 (closed without a root cause; same symptom: a Trigger is not re-reconciled when its subscriber becomes ready).

The MT broker Trigger reconciler resolves the subscriber with the Broker as the tracker parent:

subscriberAddr, err := r.uriResolver.AddressableFromDestinationV1(ctx, t.Spec.Subscriber, b)

The tracker records the parent as the observer, so it stores <namespace>/<broker-name>. The tracker callback is the Trigger controller's EnqueueKey, so when the subscriber changes, the Trigger work queue gets a key for a Trigger that does not exist (or for an unrelated Trigger that happens to share the Broker's name), and the real Trigger is not reconciled.

The broker filter dispatches to status.subscriberUri, status.subscriberCACerts and status.subscriberAudience, so this matters beyond readiness:

• a Trigger created before its subscriber is ready only recovers through the error backoff, not when the subscriber becomes addressable;
• when the subscriber's address changes (URL, CA bundle rotation, audience), the filter keeps using the old values until something else reconciles the Trigger or the resync period passes.

Every other AddressableFromDestinationV1 call in pkg/reconciler passes the object being reconciled, including the Trigger's own dead letter sink a few lines below.

Proposed Changes

• 🐛 Pass the Trigger, not the Broker, as the tracker parent when resolving the subscriber

Pre-review Checklist

• At least 80% unit test coverage
• E2E tests for any new behavior
• Docs PR for any user-facing impact
• Spec PR for any new API feature
• Conformance test for any change to the spec

Testing

TestReconcileTracksSubscriberForTrigger reconciles a Trigger whose subscriber does not exist yet, using a real tracker, and checks the observers recorded for the subscriber. On main it fails with test-namespace/test-broker as the observer; with the fix it is test-namespace/test-trigger. go test ./pkg/reconciler/broker/..., go vet and golangci-lint on the package pass.

Release Note

Triggers of the MT channel based broker are now reconciled when their subscriber changes, so the subscriber URI, CA certs and audience used by the broker filter stay current.

Docs

AI disclosure: written with the help of Claude Code, reviewed and tested by me.

[knative-prow]

Welcome @lbarrosby! It looks like this is your first PR to knative/eventing 🎉

[knative-prow]

Hi @lbarrosby. Thanks for your PR.

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[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 51.34%. Comparing base (515e11e) to head (395a616).
⚠️ Report is 2 commits behind head on main.

Additional details and impacted files

@@           Coverage Diff           @@
##             main    #9509   +/-   ##
=======================================
  Coverage   51.33%   51.34%           
=======================================
  Files         411      411           
  Lines       22187    22187           
=======================================
+ Hits        11389    11391    +2     
+ Misses       9916     9915    -1     
+ Partials      882      881    -1     

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[Cali0707]

/ok-to-test

[Cali0707]

/lgtm
/approve

[knative-prow]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: Cali0707, lbarrosby

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[lbarrosby]

/retest