As we are finding out from the conversation in https://github.com/apache/incubator-pekko/pull/273 (A PR that involves updating Jackson version due to CVE's/other complications which forces an update to Scala 3.2 due to Jackson 2.14.2 only supporting Scala 3.1) a lot of the source/compiler warnings are from Scala 3.2, not Scala 3.3.
If the PR lands, this means that the argument for avoiding updating to Scala 3.3 due to syntax/source incompatibilities is weaker since we are already forced to do the most of the same changes anyways. Furthermore as can be seen from Jackson 2.14.2 not supporting older Scala 3 versions it appears that some of the critical parts of the ecosystem are updating Scala 3 as it releases new minor versions rather than leaving it at older versions. On Fri, Mar 24, 2023 at 4:15 PM Matthew Benedict de Detrich < matthew.dedetr...@aiven.io> wrote: > > Good point also about 2.12 compatibility. It will become harder to > support multiple Scala version the more the allowed syntax differs. > > The reason why I did the PR was to actually confirm/deny whether this is > an issue, as shown in the PR its a non issue (assuming that Scala 3.3 > doesn't add anything more between RC3 and release which is quite likely) > > On Fri, Mar 24, 2023 at 3:52 PM Johannes Rudolph < > johannes.rudo...@gmail.com> wrote: > >> Just for the record, I also said not to do anything right now about it :) >> >> Other than that, I mostly agree with Nicolas. Unless we are forced to >> update Scala 3 we should *not* do it right now. The situation might >> change in 6-12 months with widespread adoption to Scala 3.3 we might >> just do it (because everyone does by then and updates will only be >> available for 3.3 at some point in the future). >> >> Good point also about 2.12 compatibility. It will become harder to >> support multiple Scala version the more the allowed syntax differs. >> >> On Fri, Mar 24, 2023 at 1:31 PM Matthew Benedict de Detrich >> <matthew.dedetr...@aiven.io.invalid> wrote: >> > >> > > One precondition to upgrade to newer versions of Scala 3 would be >> dropping >> > support for Scala 2.12. >> > Scala 2.13 at least has support for some of the Scala 3 Syntax with >> > compiler flags to cross compile. >> > >> > Are you talking about support on artifact level or on syntax level? >> Afaik >> > there isn't any plan for Scala 3.3 to drop support for Scala 2.13 >> artifacts >> > (artifacts are completely separated from supported syntax). If we are >> > talking about a hypothetical Scala 3 user of Pekko, the Scala3 syntax >> that >> > Pekko happens to use will be irrelevant here. In other words, if a user >> is >> > upgrading from Scala 3.1/Scala 3.2 to Scala 3.3 then they will have to >> > upgrade the syntax of the source code irrespective of Pekko. If we are >> > talking about difficulties of cross compiling for Scala 3/Scala 2 within >> > Pekko itself I think we would have to see if there are any syntax >> breaking >> > changes in this regard (I didn't see any for Scala 3.3 but I may have >> > missed something). Since an RC for Scala 3.3 is out we can pretty easily >> > figure out if this is going to be a problem right now. >> > >> > I think what Johannes said here is important, which is that currently >> there >> > aren't any users of Pekko Scala 3 and because of this we really >> shouldn't >> > overthink it. And even then, if we do release Pekko with Scala 3.3 and >> some >> > hypothetical user is going to have problems because they haven't >> upgrade to >> > Scala 3.3 yet, they can easily use the Pekko Scala 2.13 artifact and >> since >> > we are not using any bespoke Scala 3 features in Pekko currently on a >> > source level the user is actually not going to notice any difference. >> > >> > On Fri, Mar 24, 2023 at 1:18 PM Nicolas Vollmar <nvoll...@gmail.com> >> wrote: >> > >> > > IMHO we should use the lowest supported version of Scala 3 to not >> force >> > > user to upgrade to newer versions. >> > > >> > > Scala 3 continues to deprecate old syntax. Some of it will produce >> warnings >> > > in Scala 3.2 and may be removed in 3.3 or later. >> > > For example >> > > >> https://dotty.epfl.ch/docs/reference/dropped-features/package-objects.html >> > > or https://dotty.epfl.ch/docs/reference/changed-features/imports.html >> > > >> > > One precondition to upgrade to newer versions of Scala 3 would be >> dropping >> > > support for Scala 2.12. >> > > Scala 2.13 at least has support for some of the Scala 3 Syntax with >> > > compiler flags to cross compile. >> > > >> > > >> > > >> > > On Fri, 24 Mar 2023 at 10:26, Matthew Benedict de Detrich >> > > <matthew.dedetr...@aiven.io.invalid> wrote: >> > > >> > > > So some discussions on github are popping up regarding which Scala 3 >> > > > version we should pick so I think it's time to discuss this >> formally on >> > > the >> > > > mailing list. >> > > > >> > > > As a precursor one thing people need to understand is that the >> Scala 3 >> > > > release cycle has changed, quoting from >> > > > >> > > >> https://github.com/apache/incubator-pekko/issues/6#issuecomment-1302701657 >> > > > >> > > > > Scala 2 used epoch.major.minor version convention. Scala 3 has >> > > > major.minor.patch. >> > > > >> > > > > So there is no 3.0/3.1/3.2/etc cross-compilation - the assumption >> is >> > > > that: >> > > > >> > > > > * you can compile against the same minor version with backward- >> and >> > > > forward-compatibility: 3.1.3 dependency against 3.1.0 code, 3.0.0 >> > > > dependency against 3.0.1 code, etc >> > > > > * within the same major version you always have >> backward-compatibility: >> > > > 3.1.3 dependency can be used in 3.1.3 project, but also 3.2.0 >> project and >> > > > in future against 3.3.0 project >> > > > >> > > > This means that if we pick a Scala version, we are essentially >> forcing >> > > the >> > > > potential Scala 3 users of Pekko to bump their Scala 3 version to >> the >> > > minor >> > > > that we decide on. On surface value this means that we should pick >> the >> > > > lowest Scala 3 minor version that we can support however there is >> the >> > > fact >> > > > that Scala 3.3 is going to come out soon which will be an LTS >> release. >> > > The >> > > > LTS release means that if any bugs are found after Scala 3.3 for a >> period >> > > > of 2 years, they will be backported to Scala 3.3. The big advantage >> this >> > > > brings us, is that it allows us to freely bump Scala 3.3 without >> breaking >> > > > our users if any potential bugs are found in the future. If we >> decide to >> > > > stick with Scala 3.2 or 3.1 and some bug is found in Scala 3 later >> on >> > > that >> > > > affects us, we will have to update to a version of Scala 3 that will >> > > break >> > > > binary compatibility. This facet is of even more importance when >> > > > considering our 1.0.x release branches, which are designed to never >> break >> > > > binary/backwards compatibility, i.e. if we do 1.0.x releases with >> Scala >> > > > 3.1/3.2 and some critical bug/CVE comes out later we could >> potentially be >> > > > forced to update the minor version which would break this >> > > binary/backwards >> > > > compatibility, this wouldn't be the case with Scala 3.3 (for a >> certain >> > > > period of time). >> > > > >> > > > Of course the counter argument to using Scala 3.3 is that it would >> force >> > > > all potential Pekko users (and the transitive set of Scala 3 >> libraries >> > > for >> > > > that Pekko user) to also use/support Scala 3.3. Unfortunately its >> not >> > > > possible to get download stats from Sonatype for artifacts you don't >> > > > maintain, but I wouldn't say its a controversial statement that the >> > > amount >> > > > of people that use Akka long with Scala 3 would be a tiny minority >> (this >> > > is >> > > > also regarding other factors, i.e. the typical demographic of Akka >> > > users). >> > > > Ontop of this we need to take into account the delay of current Akka >> > > users >> > > > migrating to Pekko, in other words by the time people migrate to >> using >> > > > Pekko the fact that its using Scala 3.3 LTS would likely be a non >> concern >> > > > at that point in time. >> > > > >> > > > And finally another thing to note is that even in the worst case >> > > scenario, >> > > > nothing is stopping users from using Scala 2 artifacts from within >> Scala >> > > 3 >> > > > (this is perfectly supported and has been for a while). Afaik the >> current >> > > > Scala 3 version of Akka/Pekko is not using any unique/bespoke >> features of >> > > > Scala 3, if true this would mean from a Scala 3 user perspective >> there >> > > > really isn't going to be >> > > > a difference in using a Scala 2 artifact vs Scala 3 artifact. >> > > > >> > > > For these reasons my recommendation would be, assuming that the full >> > > > release of Scala 3.3 LTS is ready by the time we decide to make a >> release >> > > > that we should try and target that. For details on the current >> release >> > > > schedule for Scala 3.3 LTS you can read >> > > > https://contributors.scala-lang.org/t/3-3-0-release-thread/6079/3. >> > > > >> > > > -- >> > > > >> > > > Matthew de Detrich >> > > > >> > > > *Aiven Deutschland GmbH* >> > > > >> > > > Immanuelkirchstraße 26, 10405 Berlin >> > > > >> > > > Amtsgericht Charlottenburg, HRB 209739 B >> > > > >> > > > Geschäftsführer: Oskari Saarenmaa & Hannu Valtonen >> > > > >> > > > *m:* +491603708037 >> > > > >> > > > *w:* aiven.io *e:* matthew.dedetr...@aiven.io >> > > > >> > > >> > >> > >> > -- >> > >> > Matthew de Detrich >> > >> > *Aiven Deutschland GmbH* >> > >> > Immanuelkirchstraße 26, 10405 Berlin >> > >> > Amtsgericht Charlottenburg, HRB 209739 B >> > >> > Geschäftsführer: Oskari Saarenmaa & Hannu Valtonen >> > >> > *m:* +491603708037 >> > >> > *w:* aiven.io *e:* matthew.dedetr...@aiven.io >> >> --------------------------------------------------------------------- >> To unsubscribe, e-mail: dev-unsubscr...@pekko.apache.org >> For additional commands, e-mail: dev-h...@pekko.apache.org >> >> > > -- > > Matthew de Detrich > > *Aiven Deutschland GmbH* > > Immanuelkirchstraße 26, 10405 Berlin > > Amtsgericht Charlottenburg, HRB 209739 B > > Geschäftsführer: Oskari Saarenmaa & Hannu Valtonen > > *m:* +491603708037 > > *w:* aiven.io *e:* matthew.dedetr...@aiven.io > -- Matthew de Detrich *Aiven Deutschland GmbH* Immanuelkirchstraße 26, 10405 Berlin Amtsgericht Charlottenburg, HRB 209739 B Geschäftsführer: Oskari Saarenmaa & Hannu Valtonen *m:* +491603708037 *w:* aiven.io *e:* matthew.dedetr...@aiven.io
