[PR] fix: fail requests still queued in a pool interface that stops [pekko-http]

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

pjfanning opened a new pull request, #1282:
URL: https://github.com/apache/pekko-http/pull/1282

   ### Motivation
   `PoolInterface.Logic` keeps requests the pool cannot take yet in an `ArrayDeque` of `RequestContext`s, each holding the promise that the caller of `Http().singleRequest` (or of a cached host connection pool flow) is waiting on.
   
   When the stage stops without having dispatched them — the pool flow failing or cancelling, or the materializer shutting down — `postStop` only failed `shutdownPromise`. Nothing else holds those queued contexts: they were never handed to a connection, so no response, no error and no retry through the pool master can ever reach them, and the callers' `Future[HttpResponse]`s stay uncompleted for the lifetime of the process.
   
   Note that this is only reachable on the abnormal stop paths: a requested shutdown waits for `remainingRequested` to reach `0`, which counts the queued requests too.
   
   ### Modification
   Drain the buffer in `postStop` and fail every queued response promise with the same `IllegalStateException` already used for the shutdown promise.
   
   ### Result
   A pool that stops unexpectedly fails the requests it never dispatched instead of leaving their callers waiting forever.
   
   ### Tests
   - New `PoolInterfaceSpec`: the interface stage is joined to probes, three requests are queued while the pool signals no demand, and the pool flow is then completed. The test asserts all three promises fail. Reverting only the `postStop` change makes it fail — the promises are never completed.
   - `sbt "http-core/testOnly org.apache.pekko.http.impl.engine.client.PoolInterfaceSpec"` — pass (1 test).
   - `sbt "http-core/mimaReportBinaryIssues"` — pass.
   - `scalafmt --mode diff-ref=upstream/main --test` — pass.
   
   ### References
   None — found while auditing `src/main` for resource leaks.
   


-- 
This is an automated message from the Apache Git Service.
To respond to the message, please log on to GitHub and use the
URL above to go to the specific comment.

To unsubscribe, e-mail: notifications-unsubscribe@pekko.apache.org

For queries about this service, please contact Infrastructure at:
users@infra.apache.org


---------------------------------------------------------------------
To unsubscribe, e-mail: notifications-unsubscribe@pekko.apache.org
For additional commands, e-mail: notifications-help@pekko.apache.org

Re: [PR] fix: fail requests still queued in a pool interface that stops [pekko-http]

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

pjfanning merged PR #1282:
URL: https://github.com/apache/pekko-http/pull/1282


-- 
This is an automated message from the Apache Git Service.
To respond to the message, please log on to GitHub and use the
URL above to go to the specific comment.

To unsubscribe, e-mail: notifications-unsubscribe@pekko.apache.org

For queries about this service, please contact Infrastructure at:
users@infra.apache.org


---------------------------------------------------------------------
To unsubscribe, e-mail: notifications-unsubscribe@pekko.apache.org
For additional commands, e-mail: notifications-help@pekko.apache.org