[improve][broker] Use full bundle name for namespace bundle destination affinity in ModularLoadManagerImpl

[Demogorgon314]

Motivation

When unloading a namespace bundle with destinationBroker under ModularLoadManagerImpl, the affinity key was stored by bundleRange only.

Different namespaces can share the same bundle range, especially for single-bundle namespaces such as 0x00000000_0xffffffff. In that case, the destination affinity can collide across namespaces, and the next lookup may
consume the affinity for the wrong bundle.

As a result, unload --destinationBroker may appear ineffective or unstable when transferring multiple bundles that share the same range.

Modifications

• Store namespace bundle destination affinity by full bundle name instead of bare bundleRange.
• Consume the destination affinity in ModularLoadManagerWrapper#getLeastLoaded by full bundle name as well.
• Add an admin-side test to verify the affinity key passed to the load manager is the full bundle name.
• Add a load manager test to verify affinity lookup is resolved by full bundle name.

Does this pull request potentially affect one of the following parts:

If the box was checked, please highlight the changes

• 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

[Copilot]

Pull request overview

This PR fixes destination-broker affinity collisions during namespace bundle unloads under ModularLoadManagerImpl by keying affinity with the full bundle name (namespace + range) instead of only the bundle range, ensuring bundles from different namespaces don’t overwrite each other.

Changes:

• Update ModularLoadManagerWrapper#getLeastLoaded to consume affinity using the full ServiceUnitId string (full bundle name).
• Update admin unload path (NamespacesBase#setNamespaceBundleAffinityAsync) to store affinity using the resolved full bundle name.
• Add a load manager test to ensure affinity lookup is resolved by full bundle name for bundles sharing the same range.

Reviewed changes

Copilot reviewed 3 out of 3 changed files in this pull request and generated 1 comment.

File	Description
pulsar-broker/src/main/java/org/apache/pulsar/broker/loadbalance/impl/ModularLoadManagerWrapper.java	Consume namespace bundle affinity using the full bundle name rather than extracted bundle range.
pulsar-broker/src/main/java/org/apache/pulsar/broker/admin/impl/NamespacesBase.java	Store namespace bundle affinity under the full bundle name derived from (namespace, bundleRange).
pulsar-broker/src/test/java/org/apache/pulsar/broker/loadbalance/impl/ModularLoadManagerImplTest.java	Add coverage to validate affinity lookup is independent across namespaces that share the same range.