Does KSP `2.1.0-RC-1.0.26` support KSP1? I thought...

# ksp

[Robert Jaros]

Does KSP 2.1.0-RC-1.0.26 support KSP1? I thought Kotlin 2.1 will no longer support KSP1 ? But after upgrading to RC my project works as always with ksp.useKSP2=false and fails when I turn it on (probably because of https://github.com/google/ksp/issues/1854).

[Ting-Yuan Huang]

Yes, KSP1 should work with Kotlin 2.1.0 if there's no 2.1+ language features, which are all disabled by default, enabled. Even if some of them are enabled, as long as the old K1 can parse and analyze the code, KSP1 will still mostly work.

[Ting-Yuan Huang]

btw, KSP 2.0.21-1.0.27 is just released with the above issue #1854 fixed.

[eygraber]

Is there a future where Kotlin and KSP1 are incompatible because Kotlin issues still aren't resolved (e.g. KT-57919 and KT-59526)?

[Ting-Yuan Huang]

Yes, but KSP1 will be replaced by KSP2 long before that happens.

[eygraber]

But KSP2 isn't usable because of those issues.

[Ting-Yuan Huang]

In this specific case, where annotation default value is concerned, it doesn't work on KSP1 on platforms other than JVM, either. In KSP2 we recently implemented a java class walker similar to KSP1.

[eygraber]

I'm pretty sure it works with KSP1 but not KSP2. Unless it's actually a separate issue.

[eygraber]

Looks like it was a separate issue all along that was fixed in 1.0.26 😅

However https://github.com/google/ksp/issues/1854 is still broken for me even on 1.0.27.

[Ting-Yuan Huang]

For #1854, if we are talking about this thread, I'd really appreciate a reproducible project / commit.

[Ting-Yuan Huang]

Is it this one? https://github.com/evant/kotlin-inject/pull/350

[eygraber]

Yes, that is the repro