Hey Christo, could we include fixes for two usability issues in the new RC? They are minor low-risk changes, but it would be good to include them. Let me know, so I can cherry-pick them today.
- https://github.com/apache/kafka/commit/7fa5121a172e4ac0248c15e73d5833dcec9bb7d8 - https://github.com/apache/kafka/commit/c552631801f709ff7d1090b99dd5f0053d5c08ce Cheers, Lucas On Mon, Jan 19, 2026 at 11:34 AM Christo Lolov <[email protected]> wrote: > > Heya David, > > Yes, it makes sense for these to be cherry-picked, I will be creating > RC1 later today, so I will cherry-pick them beforehand, thanks for > bringing these to my attention! > > I am now closing the voting thread for RC0! > > Best, > Christo > > On Fri, 16 Jan 2026 at 13:39, David Jacot via dev <[email protected]> > wrote: > > > > Hi Christo, > > > > If we cut a new RC, I wonder if we could include the fixes for > > https://issues.apache.org/jira/browse/KAFKA-19233. They are all very small > > changes (with a lot of tests). It may be helpful for Queues and Streams to > > go GA. What do you think? > > > > Best, > > Davud > > > > On Fri, Jan 16, 2026 at 12:23 PM Christo Lolov <[email protected]> > > wrote: > > > > > Heya Paolo, > > > > > > Thanks for catching this and providing a fix! It makes sense to me > > > that since this is part of Kafka Connect's REST API it is public and > > > therefore we can't change the output without a corresponding KIP. I > > > have reviewed the PR and I am happy to cherry-pick it once it has made > > > it into trunk and include it in RC1. > > > > > > Best, > > > Christo > > > > > > On Fri, 16 Jan 2026 at 10:33, Paolo Patierno <[email protected]> > > > wrote: > > > > > > > > FYI I opened https://issues.apache.org/jira/browse/KAFKA-20076 and also > > > a > > > > corresponding PR to fix the issue here > > > > https://github.com/apache/kafka/pull/21318 > > > > It's against trunk but I think we should (if/when approved) cherry-pick > > > to > > > > 4.2.0. > > > > > > > > Thanks, > > > > Paolo > > > > > > > > On Thu, 15 Jan 2026 at 17:01, Paolo Patierno <[email protected]> > > > > wrote: > > > > > > > > > Hello, > > > > > I think I have found a regression. > > > > > When running Kafka Connect and submitting an HTTP GET request to the > > > > > /connector-plugins endpoint, the JSON serialized "type" filed in the > > > body > > > > > response is now uppercase instead of being lowercase as in the past. > > > > > Following a comparison between Apache Kafka 4.1 ... > > > > > > > > > > > > > > > > > > [{"class":"org.apache.kafka.connect.mirror.MirrorCheckpointConnector","type":"source","version":"4.1.1"},{"class":"org.apache.kafka.connect.mirror.MirrorHeartbeatConnector","type":"source","version":"4.1.1"},{"class":"org.apache.kafka.connect.mirror.MirrorSourceConnector","type":"source","version":"4.1.1"}] > > > > > > > > > > ... and the current Apache Kafka 4.2 RC0 > > > > > > > > > > > > > > > > > > [{"class":"org.apache.kafka.connect.mirror.MirrorCheckpointConnector","type":"SOURCE","version":"4.2.0"},{"class":"org.apache.kafka.connect.mirror.MirrorHeartbeatConnector","type":"SOURCE","version":"4.2.0"},{"class":"org.apache.kafka.connect.mirror.MirrorSourceConnector","type":"SOURCE","version":"4.2.0"}] > > > > > > > > > > As you can see it's "source" vs "SOURCE". I had same result with > > > "sink" vs > > > > > "SINK". > > > > > > > > > > I think this is due to the last change from converting the PluginInfo > > > from > > > > > being a class to a record which had an impact together with the JSON > > > > > serialization. > > > > > When it was a class, a dedicated type.toString() was used which > > > explicitly > > > > > does a lower case transformation. > > > > > As a record, the "type" field is directly serialized by JSON by using > > > the > > > > > enum values from PluginType which are all uppercase of course. > > > > > It means that this issue affects all the other values as well the way > > > they > > > > > are serialized (not just SINK, SOURCE but also CONVERTER, > > > TRANSFORMATION, > > > > > and so on). > > > > > > > > > > If you like I could provide a contribution for that. > > > > > > > > > > Thanks, > > > > > Paolo. > > > > > > > > > > On Tue, 13 Jan 2026 at 17:04, Christo Lolov <[email protected]> > > > > > wrote: > > > > > > > > > >> Hello Kafka users, developers and client-developers, > > > > >> > > > > >> This is the RC0 candidate for release of Apache Kafka 4.2.0. > > > > >> > > > > >> This release has many exciting changes such as Kafka Queues being > > > > >> marked as production-ready, dead letter queues in Kafka Streams, a > > > > >> preview of the new Kafka Streams rebalance protocol, improved > > > > >> consistency across Kafka CLI arguments and metrics! > > > > >> > > > > >> I will raise a PR with a new blog post to the kafka-site repository > > > > >> in > > > > >> the next 24 hours and share the link as a reply to this thread. > > > > >> > > > > >> Release notes for the 4.2.0 release: > > > > >> > > > https://dist.apache.org/repos/dist/dev/kafka/4.2.0-rc0/RELEASE_NOTES.html > > > > >> > > > > >> *** Please download, test and vote by Wednesday, January 21, 10am UTC > > > > >> > > > > >> Kafka's KEYS file containing PGP keys we use to sign the release: > > > > >> https://kafka.apache.org/KEYS > > > > >> > > > > >> * Release artifacts to be voted upon (source and binary): > > > > >> https://dist.apache.org/repos/dist/dev/kafka/4.2.0-rc0/ > > > > >> > > > > >> * Docker release artifacts to be voted upon: > > > > >> apache/kafka:4.2.0-rc0 > > > > >> apache/kafka-native:4.2.0-rc0 > > > > >> > > > > >> * Maven artifacts to be voted upon: > > > > >> > > > https://repository.apache.org/content/groups/staging/org/apache/kafka/ > > > > >> > > > > >> * Javadoc: > > > > >> > > > https://dist.apache.org/repos/dist/dev/kafka/4.2.0-rc0/javadoc/index.html > > > > >> > > > > >> * Tag to be voted upon (off 4.2 branch) is the 4.2.0 tag: > > > > >> https://github.com/apache/kafka/releases/tag/4.2.0-rc0 > > > > >> > > > > >> * Documentation: > > > > >> I will raise a PR with the changes to the kafka-site repository in > > > > >> the > > > > >> next 24 hours and share the link as a reply to this thread. > > > > >> > > > > >> * Protocol: > > > > >> I will raise a PR with the changes to the kafka-site repository in > > > > >> the > > > > >> next 24 hours and share the link as a reply to this thread. > > > > >> > > > > >> * Successful CI builds for the 4.2 branch: > > > > >> Unit/integration tests: > > > > >> > > > https://github.com/apache/kafka/actions/runs/20953445348/job/60245258542 > > > > >> System tests: My environment needs to be recreated before I can share > > > > >> results from my end, so any results shared by voters would be greatly > > > > >> appreciated! > > > > >> > > > > >> * Successful Docker Image Github Actions Pipeline for 4.2 branch: > > > > >> Docker Build Test Pipeline (JVM): > > > > >> https://github.com/apache/kafka/actions/runs/20962291986 > > > > >> Docker Build Test Pipeline (Native): > > > > >> https://github.com/apache/kafka/actions/runs/20958037429 > > > > >> > > > > >> Note - when I run the quickstart against the JVM Docker image I need > > > > >> to specify the process.roles. I do not seem to need to specify the > > > > >> process.roles if I run the 4.1.1 image. I will run this once again > > > > >> tomorrow in another clean environment, but if somebody else can > > > > >> confirm/deny whether they can reproduce this beforehand this would > > > > >> also be greatly appreciated! > > > > >> > > > > >> Thanks, > > > > >> Christo > > > > >> > > > > > > > > > > > > > > > -- > > > > > Paolo Patierno > > > > > > > > > > *Senior Principal Software Engineer @ IBM**CNCF Ambassador* > > > > > > > > > > Twitter : @ppatierno <http://twitter.com/ppatierno> > > > > > Linkedin : paolopatierno <http://it.linkedin.com/in/paolopatierno> > > > > > GitHub : ppatierno <https://github.com/ppatierno> > > > > > > > > > > > > > > > > > -- > > > > Paolo Patierno > > > > > > > > *Senior Principal Software Engineer @ IBM**CNCF Ambassador* > > > > > > > > Twitter : @ppatierno <http://twitter.com/ppatierno> > > > > Linkedin : paolopatierno <http://it.linkedin.com/in/paolopatierno> > > > > GitHub : ppatierno <https://github.com/ppatierno> > > > > > -- > You received this message because you are subscribed to the Google Groups > "kafka-clients" group. > To unsubscribe from this group and stop receiving emails from it, send an > email to [email protected]. > To view this discussion visit > https://groups.google.com/d/msgid/kafka-clients/CANF%2Ba5d6ewsFxRCQ-ZZF%2BnstYrFejS7_5%3D-5OqXxMGzRsv5D7Q%40mail.gmail.com.
