hi Siddhartha chia_0: Sorry for the confusion. My concern is that both `ByteArrayComparator` and `increment` are being exposed as Kafka public APIs, even though they appear to be intended as Kafka internal APIs
Best, Chia-Ping Siddhartha Devineni <[email protected]> 於 2025年12月28日週日 上午2:13寫道： > Hi Chia-Ping, > > Thank you for the feedback. > > chia_0: You raised a valid concern about exposing all helper methods. I > investigated the usage of each: > > 1. increment(Bytes input): Used in "org.apache.kafka.streams.test" (the > public test utilities package for Kafka Streams), so it must remain public. > 2. BYTES_LEXICO_COMPARATOR: Used in > "org.apache.kafka.streams.state.internals package". Since this is a > different package from "org.apache.kafka.common.utils" where Bytes resides, > it must remain public (package-private access wouldn't work across > different packages). > 3. ByteArrayComparator interface: Must remain public since > BYTES_LEXICO_COMPARATOR is public and has this type. > > So while I agree it would be cleaner to minimize the API surface, these > helpers are already being used across different packages and by public test > utilities. Making them package-private would break existing internal code > and they are already effectively part of the public contract. > > chia_1: Good suggestion. > BytesSerializer in "org.apache.kafka.common.serialization" is indeed a > strong example since serialization is explicitly listed as a public API > package. I have added this to the motivation section to strengthen the > rationale. > > Best regards, > Siddhartha > > On Sat, Dec 27, 2025 at 10:28 AM Chia-Ping Tsai <[email protected]> > wrote: > > > hi Siddhartha > > > > Thanks for the KIP. The motivation makes sense to me. I have a few > > comments below. > > > > chia_0: do we need to expose all helpers, such as ByteArrayComparator and > > increment? > > > > chia_1: the bytes class is also part of serialization API. Maybe you > could > > mention that in the motivation to strengthen the rationale. > > > > Best, > > Chia-Ping > > > > > Siddhartha Devineni <[email protected]> 於 2025年12月27日 > > 上午11:47 寫道： > > > > > > Hi all, > > > > > > I would like to send a gentle reminder about KIP-1247, which proposes > to > > > make the Bytes class officially part of the public API. > > > > > > KIP link: > > > > > > https://cwiki.apache.org/confluence/display/KAFKA/KIP-1247%3A+Make+Bytes+utils+class+part+of+the+public+API > > > > > > Following the earlier discussion, the KIP has been updated to focus > only > > on > > > Bytes (the Time API will be addressed separately, as it needs more > > detailed > > > assessment). > > > > > > If there are no further concerns or feedback, I would like to call for > a > > > vote in the next few days. > > > > > > Please let me know if you have any feedback. > > > Thank you. > > > > > > Best regards, > > > Siddhartha > > > > > >> On Thu, Dec 18, 2025 at 12:15 PM Siddhartha Devineni < > > >> [email protected]> wrote: > > >> > > >> Hi Sean, > > >> > > >> Thank you for the detailed analysis of the Time interface - this is an > > >> invaluable context for when we address it in a future KIP. > > >> > > >> Your breakdown of the different responsibilities (wall clock, > monotonic > > >> clock, thread yielding, and Timer instantiation) clearly shows why it > > needs > > >> more careful consideration before making it public. > > >> I agree that a more focused interface would be preferable. > > >> > > >> As discussed, KIP-1247 now focuses only on Bytes, which is > > straightforward > > >> and uncontroversial. We shall address Time in a separate KIP where we > > can > > >> properly evaluate these design concerns you have raised. > > >> > > >> When that discussion happens, your points about: > > >> > > >> 1. Separating the different time-related responsibilities > > >> 2. The fact that many classes only need (1) or (2) > > >> 3. The possibility of splitting out Timer instantiation entirely > > >> > > >> will be valuable input for designing a cleaner public API. > > >> > > >> Thanks again for the feedback! > > >> > > >> Best regards, > > >> Siddhartha > > >> > > >> On Wed, Dec 17, 2025 at 9:49 PM Sean Quah via dev < > [email protected] > > > > > >> wrote: > > >> > > >>> Hi Siddartha and Kirk, > > >>> > > >>> Thank you for your thoughts. For future discussions, my issue with > > making > > >>> the `Time` interface public is that it tries to do 3-4 different > things > > >>> related to time depending on how you count them: > > >>> 1. Provide a wall clock (`milliseconds`) > > >>> 2. Provide a high resolution monotonic clock (`nanoseconds`, > > >>> `hiResClockMs`) > > >>> 3. Provide methods for yielding the current thread (`sleep`, > > `waitObject`, > > >>> `waitForFuture`) > > >>> 4. Provide convenience methods for instantiating `Timer`s (`timer`, > > >>> `timer`) > > >>> > > >>> Many of the classes which take a `Time` only need (1), especially in > > the > > >>> broker side, though it is arguable some of them ought to be using (2) > > (eg. > > >>> KAFKA-19888 <https://issues.apache.org/jira/browse/KAFKA-19888>). I > > would > > >>> be more supportive if `Time` was more focused and limited to (1) and > > maybe > > >>> (2). I appreciate this is easier said than done since we have to mock > > (1), > > >>> (2) and (3) together in tests. (4) could be split out entirely since > we > > >>> don't mock `Timer`s at all. `KafkaStreams` in particular seems to > > mainly > > >>> use (1) with some occasional usage of (2). > > >>> > > >>> Kind regards, > > >>> Sean > > >>> > > >>> On Wed, Dec 17, 2025 at 6:38 AM Siddhartha Devineni < > > >>> [email protected]> wrote: > > >>> > > >>>> Hi all, > > >>>> > > >>>> The KIP has been updated to include only the Bytes API to be part of > > the > > >>>> public API. > > >>>> > > >>>> Here is the KIP's link again: > > >>>> > > >>>> > > >>> > > > https://cwiki.apache.org/confluence/display/KAFKA/KIP-1247%3A+Make+Bytes+utils+class+part+of+the+public+API > > >>>> > > >>>> Thanks and best regards, > > >>>> Siddhartha > > >>>> > > >>>> On Wed, Dec 17, 2025 at 11:36 AM Siddhartha Devineni < > > >>>> [email protected]> wrote: > > >>>> > > >>>>> Hi Kirk, > > >>>>> > > >>>>> Thank you for your suggestion. > > >>>>> Yes, that seems to be so. > > >>>>> > > >>>>> Then, I will update the KIP to include only the Bytes API to be > > >>> public. > > >>>>> > > >>>>> Best regards, > > >>>>> Siddhartha > > >>>>> > > >>>>> On Wed, Dec 17, 2025 at 6:44 AM Kirk True <[email protected]> > wrote: > > >>>>> > > >>>>>> Hi Siddhartha, > > >>>>>> > > >>>>>> It seems prudent to refocus this KIP on promoting the Bytes API to > > be > > >>>>>> public and then file a separate KIP for the Time API. It's more > > >>>> overhead, > > >>>>>> but it unblock Bytes since Time seems to need a little more work. > > >>>>>> > > >>>>>> Thanks, > > >>>>>> Kirk > > >>>>>> > > >>>>>> On Tue, Dec 16, 2025, at 3:07 AM, Siddhartha Devineni wrote: > > >>>>>>> Hi all, > > >>>>>>> > > >>>>>>> Thank you for the feedback. > > >>>>>>> > > >>>>>>> @Sean, I understand your concern about "Time" not being suitable > > >>> for a > > >>>>>>> public API in its current state. > > >>>>>>> Could you elaborate on what specific issues make it a "dumping > > >>>> ground"? > > >>>>>>> > > >>>>>>> Regarding your suggestion to exclude the Streams constructors > > >>>> accepting > > >>>>>>> "Time" from the public API - I want to clarify the implications: > > >>>>>>> The constructor KafkaStreams(Topology, Properties, Time) is > > >>> currently > > >>>>>>> public and has been available for several releases. > > >>>>>>> Making it non-public or removing it would be a breaking change > that > > >>>>>> would > > >>>>>>> affect any users currently using this constructor. > > >>>>>>> > > >>>>>>> What do you have in mind? > > >>>>>>> > > >>>>>>> 1. Deprecate the constructor now and remove it in a future major > > >>>>>> version, or > > >>>>>>> 2. Make it package-private (which would break existing code > > >>>>>> immediately)? > > >>>>>>> > > >>>>>>> @Kirk, Thank you for pointing that out. > > >>>>>>> You're absolutely right that making "Time" public would require > > >>> making > > >>>>>>> "Timer" public as well, since Time.timer() returns Timer objects. > > >>>>>>> This does expand the scope considerably. > > >>>>>>> > > >>>>>>> Given this expanding scope and Sean's concerns about the Time API > > >>>>>> design, > > >>>>>>> would it make sense to split this KIP into two parts or create a > > >>>>>>> separate KIP for the "Time" API and its implications? > > >>>>>>> > > >>>>>>> Best regards, > > >>>>>>> Siddhartha > > >>>>>>> > > >>>>>>> > > >>>>>>> On Tue, Dec 16, 2025 at 6:18 AM Kirk True <[email protected]> > > >>> wrote: > > >>>>>>> > > >>>>>>>> Hi all, > > >>>>>>>> > > >>>>>>>> Sean: which parts of the Time API are the most clunky? The > > >>>>>> waitForFuture() > > >>>>>>>> and waitObject() methods seem like they could be moved > elsewhere, > > >>>> but > > >>>>>> the > > >>>>>>>> others seem OK. > > >>>>>>>> > > >>>>>>>> Siddhartha: because the Time API creates Timer objects, we'd > > >>> need to > > >>>>>>>> promote Timer to the public API, too. > > >>>>>>>> > > >>>>>>>> Thanks, > > >>>>>>>> Kirk > > >>>>>>>> > > >>>>>>>> On Fri, Dec 12, 2025, at 7:12 AM, Sean Quah via dev wrote: > > >>>>>>>>> Hi Siddhartha, > > >>>>>>>>> > > >>>>>>>>> Thanks for the KIP! I'm okay making `Bytes` public. However, > > >>> the > > >>>>>> `Time` > > >>>>>>>>> interface is a bit of a dumping ground for time-related things > > >>>> and I > > >>>>>>>> would > > >>>>>>>>> not be in favor of making it public in its current state. > > >>>>>>>>> Is it possible to exclude the streams constructors accepting > > >>>>>> `Time`s from > > >>>>>>>>> the public API instead? > > >>>>>>>>> > > >>>>>>>>> Kind regards, > > >>>>>>>>> Sean Quah > > >>>>>>>>> > > >>>>>>>>> On Sun, Dec 7, 2025 at 1:53 PM Siddhartha Devineni < > > >>>>>>>>> [email protected]> wrote: > > >>>>>>>>> > > >>>>>>>>>> Hello Kafka Community, > > >>>>>>>>>> > > >>>>>>>>>> I would like to start a discussion on KIP-1247, which > > >>> proposes > > >>>> to > > >>>>>>>>>> officially make the "Bytes" and "Time" utils classes part of > > >>>>>> Kafka's > > >>>>>>>> public > > >>>>>>>>>> API. > > >>>>>>>>>> > > >>>>>>>>>> *KIP Link:* > > >>>>>>>>>> > > >>>>>>>>>> > > >>>>>>>> > > >>>>>> > > >>>> > > >>> > > > https://cwiki.apache.org/confluence/display/KAFKA/KIP-1247%3A+Make+Bytes+and+Time+utils+classes+part+of+the+public+API > > >>>>>>>>>> > > >>>>>>>>>> *Background:* > > >>>>>>>>>> > > >>>>>>>>>> Currently, "org.apache.kafka.common.utils.Bytes" and > > >>>>>>>>>> "org.apache.kafka.common.utils.Time" are exposed through > > >>>> numerous > > >>>>>>>> public > > >>>>>>>>>> API interfaces in Kafka Streams and other components, yet > > >>> they > > >>>>>> are not > > >>>>>>>>>> officially designated as public API since the utils package > > >>> is > > >>>> not > > >>>>>>>> included > > >>>>>>>>>> in Javadoc generation. > > >>>>>>>>>> > > >>>>>>>>>> This creates confusion for users who cannot determine if > > >>> these > > >>>>>> classes > > >>>>>>>> are > > >>>>>>>>>> officially supported, and causes broken Javadoc references. > > >>>>>>>>>> > > >>>>>>>>>> *Proposal:* > > >>>>>>>>>> > > >>>>>>>>>> This KIP proposes to: > > >>>>>>>>>> > > >>>>>>>>>> 1. Include "Bytes" and "Time" in Javadoc generation, > > >>>> officially > > >>>>>>>> making > > >>>>>>>>>> them part of the public API > > >>>>>>>>>> 2. Move other internal utility classes to an "internals" > > >>>>>> subpackage > > >>>>>>>> to > > >>>>>>>>>> prevent similar issues in the future > > >>>>>>>>>> > > >>>>>>>>>> > > >>>>>>>>>> > > >>>>>>>>>> *Impact:*This change has no compatibility impact - all > > >>> classes > > >>>>>> remain > > >>>>>>>> in > > >>>>>>>>>> their current locations and no user code changes are > > >>> required. > > >>>>>>>>>> > > >>>>>>>>>> You can find more details in the attached KIP link. > > >>>>>>>>>> Looking forward to your thoughts. > > >>>>>>>>>> > > >>>>>>>>>> Thank you. > > >>>>>>>>>> > > >>>>>>>>>> Best regards. > > >>>>>>>>>> Siddhartha > > >>>>>>>>>> > > >>>>>>>>> > > >>>>>>>> > > >>>>>>> > > >>>>>> > > >>>>> > > >>>> > > >>> > > >> > > >
