Thanks, I tried the "Ahead-of-time" approach using gskGenerateAccessors but it only partially worked. A buildScr folder was created (the buildSrc.jar is empty) and adding an appengine block will compile with "gradle build" (but IntelliJ could not recognize the "appengine" block). However, the "tools" child block is not allowed.
I also tried the "Ad-hoc" approach and added this code to my build.gradle.kts:
/**
* Retrieves the [appengine][com.google.cloud.tools.gradle.appengine.core.AppEngineExtension] project extension.
*/
val Project.`appengine`: com.google.cloud.tools.gradle.appengine.core.AppEngineExtension get() =
extensions.getByName("appengine") as com.google.cloud.tools.gradle.appengine.core.AppEngineExtension
/**
* Configures the [appengine][com.google.cloud.tools.gradle.appengine.core.AppEngineExtension] project extension.
*/
fun Project.`appengine`(configure: com.google.cloud.tools.gradle.appengine.core.AppEngineExtension.() -> Unit): Unit =
extensions.configure("appengine", configure)
This is similar but IntelliJ does recognize it also.
I still cannot configure the "tools" extension that is not added directly to the project by the AppEnginePlugin