This may be bigger than compose for web, but I'm n...

# compose-web

[David Herman]

This may be bigger than compose for web, but I'm noticing that starting in 1.2.1, that I'm getting recompositions that I shouldn't for methods which take a parameter from a library module. This seems like a huge regression, so I'm guessing it's already a KI?

[David Herman]

I can file a bug / upload a repro project if necessary

[David Herman]

Basically, the behavior looks like this:

sealed interface Justification {
  object Left : Justification
  object Center: Justification
  object Right: Justification
}

@Composable
fun SpanText(text: String, just: Justification) {
    println("SpanText recomposed")
    // Use justification etc.
    Span { Text(text) }
}

If Justification is defined in the app module itself, it's fine. But if included from a library module, the println will get triggered every time.

[David Herman]

If I annotate the class with @Immutable then the recompositions stop happening. But I shouldn't have to do that.

[agrosner]

You probably need the compose compiler in that module. Is it not there?

[David Herman]

It's definitely there

[David Herman]

It was working in 1.2.0 as well

[David Herman]

I'll upload a zip file later tonight

[David Herman]

Here's the project. Feel free to let me know if anyone sees any user error.

Run :app:jsBrowserRun to see it in action.

recomposes-too-often-bug.zip

[Oleksandr Karpovich [JB]]

Thank you, David!
You’re right, it’s a regression we missed 😞

https://github.com/JetBrains/compose-jb/issues/2539

[David Herman]

No problem, hope then the report was helpful!

[Oleksandr Karpovich [JB]]

Hi @David Herman!
https://github.com/JetBrains/compose-jb/issues/2539#issuecomment-1341320188 - there is a beta build with a fix

[David Herman]

Thank you! I'll test it locally.

As someone working on a library, I'm not sure I can actually make this change and push it out to users. I'm guessing the plan there will be to wait for Compose 1.2.2? (Will that still be paired with Kotlin 1.7.20?)

[Oleksandr Karpovich [JB]]

applying that compiler plugin to your library would help too if you have functions taking Jusitification as a parameter in the lib (so IR in your klib will be optimal)

But of course when users take your lib and have their own functions with Justification as a parameter, they won’t have those optimizations unless they apply 1.3.2.2-beta01 too.

[David Herman]

Gotcha

[David Herman]

Yeah I'm more worried about the latter case.

[David Herman]

I think since I'm still pre-release, the excessive recompositions are OK for now. And I can wait for 1.2.2 (assuming it will be at most a 2-3 month wait?)

[Oleksandr Karpovich [JB]]

we expect to publish 1.2.2 quite soon (this or next week if everything else is okay)

[David Herman]

Oh wow, OK that's super great

[David Herman]

That's far quicker than I need, so even if there's a delay, I'm OK with that. (I appreciate you probably have concerns beyond just me and my little library in the corner of course)

[Oleksandr Karpovich [JB]]

The issue you found and reported is a critical thing, so we really appreciate your help 🙂

[David Herman]

Someone on my Discord found it. I'll pass on the appreciation 🙂

[David Herman]

@Oleksandr Karpovich [JB] https://github.com/JetBrains/compose-jb/releases/tag/v1.2.2 doesn't seem to mention the recomposition issue. I'm assuming it's part of it though?

[David Herman]

I just tried 1.2.2 locally and it seems to be working. Is it worth updating the release notes to mention this fix for Web?

[Oleksandr Karpovich [JB]]

Yes! thank you!