[equanz]

Motivation

Using a token supplier can keep Node.js running after client.close() completes.
The supplier's thread-safe function keeps the event loop alive while the Authentication object remains reachable.

Allowing natural process exit also requires protecting native logging from accessing an already finalized thread-safe function during shutdown.

Modifications

• Unref the supplier's thread-safe function so it allows natural process exit
• Keep callback state alive through finalization and avoid releasing an already finalized thread-safe function
• Clear the registered logging callback during finalization and synchronize native logging with finalization to prevent access to a finalized thread-safe function

Verifying this change

• Make sure that the change passes the CI checks.

This change added tests and can be verified as follows:

• Add process-exit regression tests for synchronous and asynchronous suppliers

Documentation

• doc-required
  (Your PR needs to update docs and you will update later)

• doc-not-needed
  Fixes process shutdown behavior without changing the public API or configuration.

• doc
  (Your PR contains doc changes)

• doc-complete
  (Docs have been already added)

[codelipenghui]

Code Review request for changes for commit d6e52aa.

Summary:

The change addresses retained-authentication liveness and improves logger ownership, but unreferencing the supplier exposes an unguarded native-callback/finalization race. Request changes for this lifetime issue. Focused local tests could not start because Jest is missing.

[codelipenghui]

Severity: P1

Title: Synchronize supplier finalization with native callback use

Location: src/Authentication.cc:139–141

Trigger: An idle, live producer remains reachable as the last Node event-loop handle drains, while its native connection handles a broker authentication-refresh challenge or reconnects. These background native operations do not create a ThreadSafeDeferred to keep Node alive.

Impact: The unconditional Unref permits environment teardown while a native thread is using the supplier's thread-safe function. That thread can access a freed N-API handle, causing a use-after-free or process crash during natural shutdown. Shared ownership preserves the callback container, not the underlying N-API handle.

Evidence: The finalizer only sets finalized, and only the Authentication destructor reads that flag. [TokenSupplier](<apache/pulsar-client-node/pr-510/src/Authentication.cc#L60-L76>) still calls Acquire, BlockingCall and Release without synchronization with finalization. In [Node 18's implementation](<https://raw.githubusercontent.com/nodejs/node/v18.20.8/src/node_api.cc>), environment Cleanup closes the TSFN regardless of thread_count, and Finalize deletes it after invoking the addon finalizer. Consequently, a native caller can successfully Acquire, be interrupted by environment finalization, then resume BlockingCall on the freed handle. This is reachable through [Pulsar's native authentication-challenge handling](<https://raw.githubusercontent.com/apache/pulsar-client-cpp/v4.2.0/lib/ClientConnection.cc>) and [token-supplier invocation](<https://raw.githubusercontent.com/apache/pulsar-client-cpp/v4.2.0/lib/auth/AuthToken.cc>), independently of a pending JavaScript operation. Previously, the referenced supplier prevented this natural teardown while authentication remained reachable.

Suggested fix: Coordinate supplier shutdown with native callers: prevent new calls and safely finish or cancel outstanding work before the TSFN is destroyed, or retain event-loop liveness until native users have stopped. Protect native use, not just the Authentication destructor. Add a process-exit regression involving an invoked supplier and background authentication refresh or reconnect.