CI ONLY Upgrade to Scala 2.13.0-M4

[julienrf]

Continuation of #3344.

• library
• javalib
• scalalib
• compiler
• testSuite
• scalaTestSuite
• linker
• ir
• partest
• upgrade to latest Scala (a few things have been fixed upstream, and that will impact Scala.js)
• squash commits

[julienrf]

I’ve updated the PR to use the latest Scala version to date (2.13.0-pre-91a7d72). I expect that after #3353 is merged the CI should run again but two tests are still expected to fail:

• JSExportTest#noConflictingExport until Shorten scala.collection.immutable.Seq to just Seq in type errors. scala/scala#6561 is merged,
• JSExportTest#noOverrideNamedExport (because of Fix error message for overriding type alias scala/scala#6350). This one will probably have to be copied into two versions, in compiler/src/test/scala-2.13/ and in compiler/src/test/scala-2.10_2.13.0-M3/.

[sjrd]

I merged #3353. If you still get a chance to rebase this PR on top of the latest 0.6.x before you go on vacation, it would probably make the PR close to being green again. Otherwise I'll eventually do it myself.

[sjrd]

Rebased on top of #3359 and upgraded to the latest nightly of Scala.

[sjrd]

Rebased on #3361 to validate that only changing the build, tools and CI scripts on top of #3361 is enough to get the CI passing with 2.13.0-M4.

[sjrd]

Note that the partest lists are stuck on an older version of upstream 2.13.0-M4, so they are not actually run by this PR. This is because of scala/scala-dev#512.

They last correctly ran a few days ago. IMO it's not a blocker for a release of 0.6.23 that would support 2.13.0-M4.

[SethTisue]

is this superseded by #3361?

[sjrd]

No, #3361 was only a relatively small part of this PR. It contained the minimum amount of changes that we needed to get a release out supporting M4. But there's still a lot to do, e.g., the tools API. The last commit of this PR is still relevant and will come later.

For most downstream projects, though, #3361 is enough (that was the point).

[sjrd]

Almost there. Now waiting for scala-parallel-collections to be built and published for 2.13.0-M4 ... scala/scala-parallel-collections#41

[julienrf]

Publishing the parallel collections is one month work that nobody has started yet, to my knowledge. I suggest to find a solution to not be blocked by the parallel collections.

…

On May 20, 2018 10:58:05 PM GMT+02:00, "Sébastien Doeraene" ***@***.***> wrote: Almost there. Now waiting for scala-parallel-collections to be built and published for 2.13.0-M4 ... scala/scala-parallel-collections#41

[sjrd]

That is unfortunate. Our linker is parallel because of the parallel collections.

A solution that does not involve scala-parallel-collections would require to rewrite the parallel parts of our linker not to use the parallel collections at all, which is probably also several weeks of work.

[julienrf]

This will be fixed for 2.13.0 but in the meantime is it possible for you to disable the parallel linker?

[sjrd]

Definitely not wholesale (on all Scala versions). Doing so would mean releasing sbt plugins that perform significantly worse than the current one.

We might be able to disable it when compiling for 2.13, but that would involve tricky manipulations of our source files, and we would have to revert them back when support for parallel collections catches up. That's not something I'm eager to undertake.

[sjrd]

Superseded by #3702 and #3703.