[PR] [fix][client] Reset higher-index states on recovery in SameAuthParamsLookupAutoClusterFailover [pulsar]

["merlimat (via GitHub)" <gi...@apache.org>]

merlimat opened a new pull request, #25826:
URL: https://github.com/apache/pulsar/pull/25826

   ### Motivation
   
   `SameAuthParamsLookupAutoClusterFailover` maintains a per-service-index state array (`Healthy`, `PreFail`, `Failed`, `PreRecover`) updated by a periodic check loop. The check loop only probes indices `0..currentPulsarServiceIndex`:
   
   ```java
   private void checkPulsarServices() {
       for (int i = 0; i <= currentPulsarServiceIndex; i++) {
           ...
       }
   }
   ```
   
   When we recover to a higher-priority service (`currentPulsarServiceIndex` decreases), the loop stops probing the higher-indexed services. If any of those indices were in a transient state at the moment of recovery (e.g., `PreFail` from a single timed-out probe), they get stuck there because nothing ever probes them again to flip them back to `Healthy`.
   
   This causes `SameAuthParamsLookupAutoClusterFailoverTest.testAutoClusterFailover` to fail intermittently:
   
   ```
   Caused by: java.lang.AssertionError: Arrays differ at element [2]: Healthy != PreFail expected [Healthy] but found [PreFail]
   ```
   
   Concretely: while `currentPulsarServiceIndex` is 2 and the test is waiting for index 1 to recover, a single transient probe failure on pulsar2 transitions `state[2]: Healthy -> PreFail`. A subsequent successful probe at index 1 reaches `recoverThreshold` and triggers `updateServiceUrl(1)`, dropping `currentPulsarServiceIndex` to 1. From that point on the loop only probes indices 0 and 1, and `state[2]` stays at `PreFail` forever — the test's 3-minute await window never sees `state[2] == Healthy`.
   
   Example failure: https://scans.gradle.com/s/7pttiiyo6yybc/tests/task/:pulsar-broker:test/details/org.apache.pulsar.broker.SameAuthParamsLookupAutoClusterFailoverTest/testAutoClusterFailover%5B2%5D(true)/1/output
   
   ### Modifications
   
   In `updateServiceUrl`, when recovering (target index < current index), reset state of indices above the new target to `Healthy` and zero their counters. The state of an unprobed index is not meaningful — resetting it ensures (a) a subsequent failover starts from a clean baseline if it needs to consider those services again, and (b) we don't leave stale transient state lying around.
   
   ### Verifying this change
   
   This change is already covered by `SameAuthParamsLookupAutoClusterFailoverTest.testAutoClusterFailover` (TLS and non-TLS variants). Locally I ran the test 3 times with `--rerun-tasks`; all passed in ~90s each.
   
   ### Does this pull request potentially affect one of the following parts:
   
   - [ ] Dependencies (add or upgrade a dependency)
   - [ ] The public API
   - [ ] The schema
   - [ ] The default values of configurations
   - [ ] The threading model
   - [ ] The binary protocol
   - [ ] The REST endpoints
   - [ ] The admin CLI options
   - [ ] The metrics
   - [ ] Anything that affects deployment


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Re: [PR] [fix][client] Reset higher-index states on recovery in SameAuthParamsLookupAutoClusterFailover [pulsar]

["lhotari (via GitHub)" <gi...@apache.org>]

lhotari merged PR #25826:
URL: https://github.com/apache/pulsar/pull/25826


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