Gradle 预编译脚本插件失败，第一个块出现"表达式 .. 不能作为函数调用"

Question

我有以下预编译脚本插件，它应用了一个 Gradle 核心插件和一个外部插件(通过id(...))：

// buildSrc/main/kotlin/my-template.gradle.kts:
import org.gradle.api.JavaVersion
plugins {
java
id("com.diffplug.gradle.spotless") // commenting this line "fixes" the problem, WHY?
}
java {
sourceCompatibility = JavaVersion.VERSION_11
}

有了这个build.gradle.ktsbuildSrc：

// buildSrc/build.gradle.kts:
repositories {
maven("https://nexus.ergon.ch/repository/secure-public/")
}
plugins {
`kotlin-dsl`
id("com.diffplug.gradle.spotless") version "3.25.0"
}

生成失败，并显示以下消息：Expression 'java' cannot be invoked as a function. The function 'invoke()' is not found

$ ./gradlew tasks
> Task :buildSrc:compileKotlin FAILED
The `kotlin-dsl` plugin applied to project ':buildSrc' enables experimental Kotlin compiler features. For more information see https://docs.gradle.org/5.6.4/userguide/kotlin_dsl.html#sec:kotlin-dsl_plugin
e: .../buildSrc/src/main/kotlin/my-template.gradle.kts: (8, 1): Expression 'java' cannot be invoked as a function. The function 'invoke()' is not found
e: .../buildSrc/src/main/kotlin/my-template.gradle.kts: (8, 1): Unresolved reference. None of the following candidates is applicable because of receiver type mismatch: 
internal val OrgGradlePluginGroup.java: PluginDependencySpec defined in gradle.kotlin.dsl.plugins._279e7abc24718821845464f1e006d45a in file PluginSpecBuilders.kt
public val <T> KClass<TypeVariable(T)>.java: Class<TypeVariable(T)> defined in kotlin.jvm
public val PluginDependenciesSpec.java: PluginDependencySpec defined in org.gradle.kotlin.dsl
e: .../buildSrc/src/main/kotlin/my-template.gradle.kts: (9, 5): Unresolved reference: sourceCompatibility

FAILURE: Build failed with an exception.
* What went wrong:
Execution failed for task ':buildSrc:compileKotlin'.
> Compilation error. See log for more details

我使用的是 Gradle 5.6.4，自 Gradle 5.3 以来，预编译的脚本插件应该能够利用类型安全的访问器。

(此外，java {}块在 IntelliJ 中以红色突出显示，并且没有代码完成)

一旦plugins {}块中列出了任何外部插件，就会出现此问题，它与特定的spotless插件无关。

该问题似乎总是影响plugins {}块之后的第一个块，因此它似乎也与特定的java插件无关。

我需要更改什么才能使我的插件正常工作？

Answer 1

问题是，在buildSrc/build.gradle.kts应用外部 Gradle 插件id("com.diffplug.gradle.spotless")(通过plugins {}块)，但没有在提供插件的工件上声明依赖关系(通过dependencies块)：

plugins {
`kotlin-dsl`
// use "apply false" to specify the exact version (which is
// forbidden in the pre-compiled script plugin itself) without applying the plugin
id("com.diffplug.gradle.spotless") version "3.25.0" apply false 
}
dependencies {
// actually depend on the plugin to make it available:
implementation(plugin("com.diffplug.gradle.spotless", version = "3.25.0")) 
}
// just a helper to get a syntax similar to the plugins {} block:
fun plugin(id: String, version: String) = "$id:$id.gradle.plugin:$version"