Support Kotlin Symbol Processing (KSP)

[mannodermaus]

Describe your problem or use case

Kotlin Symbol Processing (KSP) is a joint effort by Google & JetBrains and seeks to provide an API for building compiler plugins. Compared to KAPT, annotation processors that use KSP can run up to 2x faster.

Describe the solution you'd like

Introduce a sibling artifact to the realm-annotations-processor which leverages the performance and benefits of KSP over KAPT for Kotlin-based projects.

[rorbech]

@mannodermaus Thanks for the input. We are aware that KSP has been promoted to alpha, but have not yet evaluated/looked into replacing the current Realm annotation processor for Kotlin with it.

[kzotin]

Just FYI, KSP is now stable!👀

https://android-developers.googleblog.com/2021/09/accelerated-kotlin-build-times-with.html

[mannodermaus]

FWIW I was trying to help out here and look into a potential migration to KSP as an external contribution, but frankly I was unable to get Realm compiled on my machine. 🙈 Is there a rough roadmap or guidance of Realm regarding this feature?

[mannodermaus]

The Realm Kotlin SDK exists now. Is it safe to assume that KSP wouldn't be added for the older Java SDK, esp. since the new one seems to be built as a compiler plugin instead?

[rorbech]

Yes, we do not have any immediate plans to rewrite the code generation parts of realm-java with KSP. KSP would only work for Kotlin code and doesn't support transforming existing code, so wouldn't suffice for our full use case. This is also why we use compiler plugins in realm-kotlin.

[Kardelio]

Heyoooo <3 any updates on this front? Just curious as we are moving our entire project over to ksp and the last bit is the realm of it all.
Not meant to be a pressure or pain, just curious if this work (realm to ksp instead of kapt) is going to happen at some point in the future?

Just for reference, i changed our module containing realm into ksp and got this error, after searching on the net i found that the underlying generation uses kapt, which led me here :)

An exception occurred applying plugin request [id: 'realm-android']
> Failed to apply plugin 'realm-android'.
   > Configuration with name 'kapt' not found.

For now the android docs say kapt and ksp can run in parralel together so ill add kapt plugin back to this module and keep an eye on this issue <3

Thank you all btw for your amazing work on realm, just needed to be said <3

[sailorseashell]

I'd like to add my voice to asking for updates on this. We are also trying to move our project completely over from kapt and this is the last holdout!

[brucemax]

As always, the only thing that slows down our project from innovation is the realm :(

[Deni-H]

Any update on this?

[kzotin]

Since the release of Kotlin 2.0, the importance of migration to KSP increases due to:

w: Kapt currently doesn't support language version 2.0+. Falling back to 1.9.

[nirinchev]

We don't have plans to add new features to realm-java and instead recommend that you migrate to our native kotlin SDK: https://github.com/realm/realm-kotlin.

[EranBoudjnah]

This is absurd. realm-kotlin is incredibly poorly documented. There's no migration guide, which is sorely needed because the two libraries are completely different. Not a day goes by that I don't regret going with Realm. 😢

[rorbech]

@EranBoudjnah We have a migration guide that should give you an overview of the differences. It is hard to give a step-by-step guide on the actual process as it depends on your use case. Feel free to provide feedback on what items you are missing with regards of migrations and/or what you are missing from the realm-kotlin documentation.

[EranBoudjnah]

Thanks @rorbech - this helps. Let me dig into it, and I'll keep track of anything that I'm missing as I'm going through the migration.

One obvious thing is that the README on the repo https://github.com/realm/realm-kotlin disagrees with the rest of the documentation (for example, = vs == in queries). It also has code that simply doesn't work, like realm.query<Person>(...) - from what I've seen, you have to pass in the kclass to query, but that's not in the readme.

[nirinchev]

= and == are both valid equality expressions and you can use either one. Can you clarify in which case you need to pass in the kclass - realm.query<TModel>(...) should work and we do have tests for it - e.g. https://github.com/realm/realm-kotlin/blob/06aacec9db7c1f9e9c702db5bd16393c4186589d/packages/test-base/src/commonTest/kotlin/io/realm/kotlin/test/common/QueryTests.kt#L350-L355.

[EranBoudjnah]

This is taken straight out of io.realm.kotlin:library-base-android:2.1.0 (io/realm/kotlin/Realm.kt).

It's rather confusing that you can use both, since in many languages the meaning differs. It would be good for the documentation to be consistent.

As for the migration document, it's missing things like what to do with @LinkingObjects and the fact the RealmList fields become required, changing the schema.

Overall, with some guesswork, I was able to migrate my project, but I can't say it was a smooth process. Another confusing thing is that the Readme file mentions using snapshots but doesn't have instructions for the simple case of adding a stable version...

[nirinchev]

From the API docs for this method:

A reified version of this method is also available as an extension function,
realm.query<YourClass>(...). Import io.realm.query to access it.

Regarding the equality operator, the fact = and == are interchangeable is due to the fact it's impossible to do assignments inside a query expression. Most programming languages use == to express equality, which is why we wanted to be relaxed about it and not force usage of =.

Finally, the realm-kotlin readme does link to the install instructions in the installation section. The docs on mongodb.com/docs should be viewed as the authoritative source of truth and the readme is a compressed and maintainer-focused version of those docs.

[EranBoudjnah]

This doesn't seem to quite work. What am I missing?

I still think it would be helpful if the documentation was consistent in its use of either = or ==, even if the other is silently accepted. But that's just my opinion.

It's good to know that the link is the authoritative source of truth, although it seems somewhat outdated (it uses version 1.16.0).

In any case, thanks for the patience and help, @nirinchev!

[nirinchev]

Can you try io.realm.kotlin.ext.query? Looks like the reified version of the function is defined here: https://github.com/realm/realm-kotlin/blob/06aacec9db7c1f9e9c702db5bd16393c4186589d/packages/library-base/src/commonMain/kotlin/io/realm/kotlin/ext/RealmExt.kt#L28-L31

[EranBoudjnah]

Nice! This works.