Kotlinx.datetime.Instant removed, but no replacement serializer provided

[Nek-12]

Kotlinx.datetime 0.7.0 removed kotlinx.datetime.Instant, but kotlinx.serialization does not provide serializer for kotlin.time.Instant.

Please release a version that works with kotlinx.datetime 0.7.0

[Nek-12]

Cc @dkhalanskyjb

[dkhalanskyjb]

Fixed in 13a487c

[Nek-12]

Thanks! That was super fast. We can close this once a version is released

[solonovamax]

It seems like it's part of kotlinx-serialization-core 1.9.0, however if a class is marked as @Serializable and it has an Instant on it, then it reports an error:

Serializer has not been found for type 'Instant'. To use context serializer as fallback, explicitly annotate type or property with @Contextual

it is not possible to annotate it with @Serializable(with = InstantSerializer::class) either, because InstantSerializer is marked as internal.

[rasharab]

Same problem:

kotlinx.serialization/core/jvmMain/src/kotlinx/serialization/internal/Platform.kt

Line 206 in 10c7b9d

loadSafe { put(Instant::class, Instant.serializer()) }

Apparently, it seems that the addition of the serializer to the jvm platform is conditional.

[b95505017]

For the annotation issue, the root cause may be relate to serialization plugin？Without the newer plugin, annotation won't add the new Instant serializer automatically.
You could check JetBrains/kotlin@6869122 to get some idea.
13a487c only fix the manual part.

[solonovamax]

For the annotation issue, the root cause may be relate to serialization plugin？Without the newer plugin, annotation won't add the new Instant serializer automatically. You could check JetBrains/kotlin@6869122 to get some idea. 13a487c only fix the manual part.

I was using the plugin version shipped with kotlin 2.2.0, which is the latest kotlin version. at the same time as I updated kotlinx.datetime to the latest version, I also updated all my other dependencies to the latest version.

it seems to me that this change was extremely hastily done without much attempt at ensuring that everything will work smoothly for everyone. hell, the stdlib api still isn't even stable and is currently experimental. the kotlinx.datetime.Instant class should not have been removed until it was stable at the very least for a version or two.

[Nek-12]

I absolutely agree with @solonovamax , disaster of a change. The order of change is what's the most puzzling. Serializer should've been present for a month before removal, been public, ensured it works with the plugin, API out of experimental, support ensured in Compose and other major deps, then the Instant class marked as deprecated with level = WARNING, then ERROR, then HIDDEN and only then (timeline ~1y) removed. And the response that kotlinx.datetime is experimental won't work there because before the team was extremely conservative with changes in the API. Thousands of libraries were using the instant class and are now forced to hastily produce two different versions of their library to support migrations of their users. A fundamental change on the level of kotlin language itself was done in a minor version release with no migration path.

I hope @dkhalanskyjb 's manager (or whoever's orchestrated the migration) doesn't see this thread. :D

[b95505017]

For the annotation issue, the root cause may be relate to serialization plugin？Without the newer plugin, annotation won't add the new Instant serializer automatically. You could check JetBrains/kotlin@6869122 to get some idea. 13a487c only fix the manual part.

I was using the plugin version shipped with kotlin 2.2.0, which is the latest kotlin version. at the same time as I updated kotlinx.datetime to the latest version, I also updated all my other dependencies to the latest version.

it seems to me that this change was extremely hastily done without much attempt at ensuring that everything will work smoothly for everyone. hell, the stdlib api still isn't even stable and is currently experimental. the kotlinx.datetime.Instant class should not have been removed until it was stable at the very least for a version or two.

That's the problem is. The Kotlin 2.2.0 serialization plugin doesn't know about the 1.9.0 serialization library including the new Instant serializer.

I'm wondering why kotlin & kotlinx split into lots of different plugins & libraries with different release timing. Maybe all of them should follow kotlin stdlib release to prevent this type of issue. Just like compose plugin.

[fzhinkin]

@Nek-12,

I hope … manager (or whoever's orchestrated the migration) doesn't see this thread. :D

I sincerely appreciate the constructive feedback, and understand your dissatisfaction. Things could went smoother indeed, and I’m really sorry for that.
However, that’s not the reason to get personal and blame anyone particular, even in a form of a joke.
There are a lot of moving parts and people involved, so things went out of sync. The lesson will be learned, and we’ll improve both processes and the communication.

[solonovamax]

I absolutely agree with @solonovamax , disaster of a change. The order of change is what's the most puzzling. Serializer should've been present for a month before removal, been public, ensured it works with the plugin, API out of experimental, support ensured in Compose and other major deps, then marked as deprecated with level = WARNING, then ERROR, then HIDDEN and only then (timeline ~1y) removed. And the response that kotlinx.datetime is experimental won't work there because before the team was extremely conservative with changes in the API.

exactly this

I would have expected that even though it's considered to be "experimental" it's still treated with the typical support cycle, albeit a bit relaxed. because if I had to guess, it's probably a rather popular library for kotlin bc if you need to do anything with dates/timestamps it's what you'd reach for.

[Nek-12]

Thanks @fzhinkin for the understanding. You're right, I didn't mean it as a stab at a person (of course it isn't one persons effort), but didn't make it clear enough.

For now let's focus on fixing the compiler issue. Is there a 2.2.1 release planned or something? For now, is it best to copy-paste the serializer or ignore the error?