Why does the Kotlin Plugin target 1.8?

blundell · November 4, 2021, 4:02pm

gradle/gradle/blob/945171d83d3bbf5313e317c74873a70220625800/subprojects/kotlin-dsl/src/main/kotlin/org/gradle/kotlin/dsl/KotlinBuildScript.kt#L46

    
      
          * Base class for Kotlin build scripts.
          */
          @ScriptTemplateDefinition(
             resolver = KotlinBuildScriptDependenciesResolver::class,
             scriptFilePattern = ".+(?<!(^|\\.)(init|settings))\\.gradle\\.kts"
          )
          @ScriptTemplateAdditionalCompilerArguments(
             [
                 "-language-version", "1.4",
                 "-api-version", "1.4",
                 "-jvm-target", "1.8",
                 "-Xjvm-default=all",
                 "-Xjsr305=strict",
                 "-XXLanguage:+DisableCompatibilityModeForNewInference",
             ]
          )
          @SamWithReceiverAnnotations("org.gradle.api.HasImplicitReceiver")
          @GradleDsl
          abstract class KotlinBuildScript(
             private val host: KotlinScriptHost<Project>
          ) : ProjectDelegate() /* TODO:kotlin-dsl configure Project as implicit receiver */ {

Wondering why it explicitly targets 1.8 (when Java 11 LTS is available or even Java 17 now )

Chris_Dore · November 7, 2021, 7:29am

That code looks related to Kotlin Gradle buildscript support and since current Gradle versions support running in Java 8 I’m guessing that’s why.

blundell · November 8, 2021, 7:58am

Hmm Gradle 7.3 support’s java 17 Gradle 7.3-rc-1 Release Notes and on that branch/tag this is still targeting 1.8 gradle/KotlinBuildScript.kt at v7.3.0-RC5 · gradle/gradle · GitHub

Chris_Dore · November 8, 2021, 11:42pm

Yes, but Gradle still needs to be able to execute on Java 8 (the minimum supported version that Gradle 7 will run on), so its buildscript support needs to remain compatible.

Note; this has nothing to do with the bytecode generated for your application, via the Kotlin Gradle plugin. I’ve never used that plugin so I cannot comment on the details of setting the target jvm version.

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Why does the Kotlin Plugin target 1.8?

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