Thorbenl opened a new pull request, #281:
URL: https://github.com/apache/pulsar-dotpulsar/pull/281
## Summary
- `Awaiter.CreateTask` and `AddTaskCompletionSource` used
`ConcurrentDictionary.TryAdd` which silently discards the new
`TaskCompletionSource` when the key already exists
- During producer reconnection, messages are resent with the same sequence
IDs — new TCS registrations are silently dropped, so broker receipts complete
the old (cancelled) TCS instead of the new one
- This causes `ProducerSendReceiptOrderingException` in
`SubProducer.ProcessReceipt` because the receipt for the head of the send queue
is never observed
## Root Cause
When a producer reconnects (e.g. due to auth token rotation or broker
restart), `EstablishNewChannel` cancels the old dispatcher and creates a new
channel. The send queue cursor is reset, so pending messages are resent with
their original sequence IDs. In `RequestResponseHandler`,
`Awaiter.AddTaskCompletionSource` is called for each resent message — but
`TryAdd` returns `false` for duplicate keys and the new TCS is discarded. The
broker's receipt then completes the old TCS (already cancelled during channel
teardown), and the new TCS never receives a result.
## Fix
Introduced a private `AddOrReplace` method that:
1. Removes any existing entry for the key (cancelling the old TCS)
2. Adds the new TCS
This ensures resent messages always have a live TCS to receive broker
receipts.
## Tests
Added `AwaiterTests` with 8 unit tests covering:
- Basic `SetResult`, `Cancel`, `Dispose` behavior
- `SetResult` with no matching entry (no-op, no throw)
- **Duplicate key handling** via both `CreateTask` and
`AddTaskCompletionSource`:
- Old TCS is cancelled when replaced
- New TCS receives the result on `SetResult`
All 8 tests pass. Full unit test suite: 232/233 pass (1 pre-existing
`ZstdCompressionTests` failure unrelated to this change — compression library
loading on macOS ARM64).
Fix #280
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