Automatically filter package-private changes on Scala 3

[armanbilge]

This first came up in typelevel/cats#4062 (comment). We're in the process of enabling MiMa for Scala 3 for several Typelevel projects and we're having to add a lot of filters (e.g. http4s/http4s#5900). Getting support for package privates in Scala 3 on par with Scala 2 would be phenomenal. Thanks!

[armanbilge]

See also typelevel/fs2#2791 which had many MiMa issues regarding default params.

[dwijnand]

I'll try to bring package private support for Scala 3.

For the separate default parameters issue, do you have a clear example of mima warning but the program (which makes a reasonable attempt to fail) doesn't crash (aka a false positive). Or is it a dotty bug where the encoding is problematic for API migrations (e.g the static/non-static part)?

[armanbilge]

Thanks, much appreciated!

For the separate default parameters issue, do you have a clear example of mima warning but the program (which makes a reasonable attempt to fail) doesn't crash (aka a false positive). Or is it a dotty bug where the encoding is problematic for API migrations (e.g the static/non-static part)?

Apologies, no, I haven't put that together. However I did decompile the output of Scala 2.13 and Scala 3 in typelevel/fs2#2791 (comment) and it appears to me that default parameters are encoded in much the same way, except that in Scala 3 the methods are not marked as synthetic on the bytecode level which causes MiMa to flag them.

[armanbilge]

@dwijnand there wouldn't happen to be a MiMa release on the horizon? Would be nice not to have to add so many Scala 3-specific filters in typelevel/cats-effect#2857. Thanks! :)

[dwijnand]

Yep, I'll try to tee one up for next week.

[armanbilge]

@dwijnand polite bump, if you have a chance. Thanks! :)