error when depending on a library that includes latest version of `kotlinx.datetime`

[benjishults]

Sample Notebook that exposes the bug is at the bottom of this description.

If I use lets-plot in a Kotlin Notebook and the notebook depends on a library that pulls in the latest kotlinx.datetime, I get

java.lang.NoSuchMethodError: 'kotlinx.datetime.LocalDateTime kotlinx.datetime.TimeZoneKt.toLocalDateTime(kotlinx.datetime.Instant, kotlinx.datetime.TimeZone)'
	at org.jetbrains.letsPlot.commons.intern.datetime.Instant.toDateTime(Instant.kt:28)
	at org.jetbrains.letsPlot.commons.formatting.datetime.DateTimeFormatUtil.format(DateTimeFormatUtil.kt:37)

even if I'm using java.time.Instant in my data. (See notebook details at the bottom.)

This Kotlin Notebook works fine if it does depend on the library with the latest kotlinx.datetime.

lets-plot currently uses kotlinx.datetime at 0.6.2.

There are incompatibilities between this and the latest version of kotlinx.datetime (currently 0.7.1).

This ticket is to upgrade lets-plot to the latest version of kotlinx.datetime.

Sample Notebook:

%use dataframe
%use lets-plot
---
import java.math.BigDecimal

val simple = dataFrameOf("a", "b")(java.time.Instant.parse("2026-04-05T00:00:00Z"), BigDecimal.valueOf(2.0))
simple.schema()
---
a: java.time.Instant
b: java.math.BigDecimal
---
letsPlot(simple.toMap()) { x = "a"; y = "b" } + geomLine()

The above Notebook works fine unless it depends on a library that pulls in the latest version of kotlinx.datetime.

[alshan]

In a future release, we will switch to kotlinx-datetime v0.7.1-0.6.x-compat (we still need to maintain compatibility with the IDEA platform, which depends on v0.6.2).

In the meantime, could you try injecting the third-party library dependency after %use dataframe? That way, v0.7.1-0.6.x-compat (which DataFrame depends on: https://github.com/Kotlin/dataframe/blob/16e8793248585684a5cf572fa6887f0376394411/gradle/libs.versions.toml#L42) might end up on the classpath before v0.7.1 and v0.6.2.

That said, classpath ordering in Kotlin Notebooks may not be fully controllable, so this workaround isn't guaranteed.

[alshan]

Hello Benjamin Shults (@benjishults),

We attempted to upgrade the Lets-Plot datetime dependency to v0.7.1-0.6.x-compat, but it turned out that the resulting binaries are not compatible with datetime 0.6.2.

As a result, the current workaround is still to load datetime v0.7.1-0.6.x-compat before any other libraries that use datetime. In a Kotlin Notebook, the best way to achieve this is to include one of the following snippets at the top of your notebook:

@file:DependsOn("org.jetbrains.kotlinx:kotlinx-datetime:0.7.1-0.6.x-compat")

or

USE {
    dependencies {
        implementation("org.jetbrains.kotlinx:kotlinx-datetime:0.7.1-0.6.x-compat")
    }
}

In the meantime, we must wait for this dependency to be upgraded within the IDEA platform itself. I have submitted an issue for this here: IJPL-244862.

[StylianosGakis]

This does not solve the issue for users who are not using this for notebooks I assume?

I am building a desktop application using compose and it seems like my options are to either downgrade everything else too to make it work with the old datetime version, or to stop using lets-plot completely, right?

[alshan]

Hi stylianosgakis (@StylianosGakis) ,
If the conflict in your desktop app comes from lets-plot-kotlin transitively bringing in kotlinx-datetime:0.6.2, you can:

• Use dep-free lets-plot artifact - org.jetbrains.lets-plot:lets-plot-kotlin-kernel
  See the tip in the "Compose/Desktop" section here: https://github.com/JetBrains/lets-plot-compose#compose-multiplatform-for-desktop

• Or try to exclude the transitive deps:

implementation("org.jetbrains.lets-plot:lets-plot-kotlin:4.14.0") {
     exclude(group = "org.jetbrains.kotlinx", module = "kotlinx-datetime")
}

And if datetime is actually used in charts you also need to make sure kotlinx-datetime compat version is in runtime deps.

[alshan]

In 4.14.1 the datetime dependency was upgraded to 0.7.1