Hi Bill, Thanks for the suggestions! I have made some changes accordingly. BB1: I changed the 4 added methods to use `by` instead of `on`. BB2: For each deprecated method, an additional warning comment will be added, stressing that the `readOnlyKey` is the stream key and might not be behaving as intended.
Best, Lucy On Wed, May 27, 2026 at 4:07 PM Bill Bejeck <[email protected]> wrote: > Hi Lucy, > > Thanks for the KIP! This is a very much needed update to Kafka Streams. > Overall the KIP looks good. > > BB1. I have one nit comment with regards to the name. What would you think > about `joinByMappedKey / leftJoinByMappedKey` instead? > BB2. Since the error condition will continue to exist until we remove the > deprecated methods, maybe we could add one line to the Javadoc explicitly > stating that readOnlyKey is currently the stream key, not the mapped join > key. > > Thanks, > Bill > > On Tue, May 26, 2026 at 1:19 PM Lucy Liu via dev <[email protected]> > wrote: > > > Hi everyone, > > > > Gentle ping on this thread. Looking forward to feedback on the KIP! > > > > Best, > > Lucy Liu > > > > On Fri, May 15, 2026 at 4:19 PM Lucy Liu <[email protected]> wrote: > > > > > Hello everyone, > > > > > > I would like to start a discussion on KIP-1340 Pass Join Key to > > > `ValueJoinerWithKey` in Streams-GlobalKTable Joins > > > < > > > > > > https://urldefense.com/v3/__https://cwiki.apache.org/confluence/display/KAFKA/KIP-1340*3A*Pass*Join*Key*to**A60ValueJoinerWithKey*60*in*Streams-GlobalKTable*Joins__;JSsrKysrJSUrKys!!Ayb5sqE7!sMsc7OEJtzyBJn3kfDmAjAi8gklV-8hDbb2Oiwk_NV0RC8giJPWimU7sX4jc4Niu_29yjxAv1souD4H5kUY$ > > > > > > > > > > This proposal aims to introduce joinOnMappedKey and > leftJoinOnMappedKey, > > > new KStream methods that pass the mapped join key (the result of the > > > user-supplied KeyValueMapper) into ValueJoinerWithKey for > > > stream-globalTable joins. The existing join/leftJoin overloads pass the > > > stream record's key into the joiner instead, contradicting KIP-149's > > > contract that readOnlyKey is the join key and silently producing wrong > > > values if a joiner intends to read the real join key. The existing > > > overloads will be deprecated and removed in a future major release. > > > > > > Best regards, > > > Lucy Liu > > > > > >
