Gradle中splain插件Java兼容性不符？如何禁用消费端检查？

我正尝试为Scala 2.13.11使用splain插件1.0.2。根据其构建定义文件，它被声明为兼容Java 1.8及以上版本：

tasks {
    val jvmTarget = JavaVersion.VERSION_1_8.toString()

    withType<ScalaCompile> {
        targetCompatibility = jvmTarget
    }
}

但将其作为Scala编译器插件引入时：

val splainD = "io.tryp:splain_2.13.11:1.0.2"
scalaCompilerPlugins(splainD)

我遇到了如下错误：

Execution failed for task ':prover-commons:core:compileTestFixturesScala'.

Could not resolve all files for configuration ':prover-commons:core:testFixturesCompileClasspath'.

Could not resolve io.tryp:splain_2.13.11:1.0.2.

Required by:
project :prover-commons:core

No matching variant of io.tryp:splain_2.13.11:1.0.2 was found. The consumer was configured to find a library for use during compile-time, compatible with Java 8, preferably in the form of class files, preferably optimized for standard JVMs, and its dependencies declared externally but:

• Variant 'apiElements' capability io.tryp:splain_2.13.11:1.0.2 declares a library for use during compile-time, packaged as a jar, and its dependencies declared externally:

• Incompatible because this component declares a component, compatible with Java 11 and the consumer needed a component, compatible with Java 8
• Other compatible attribute:

• Doesn't say anything about its target Java environment (preferred optimized for standard JVMs)

• Variant 'javadocElements' capability io.tryp:splain_2.13.11:1.0.2 declares a component for use during runtime, and its dependencies declared externally:

• Incompatible because this component declares documentation and the consumer needed a library
• Other compatible attributes:

• Doesn't say anything about its target Java environment (preferred optimized for standard JVMs)
• Doesn't say anything about its target Java version (required compatibility with Java 8)
• Doesn't say anything about its elements (required them preferably in the form of class files)

• Variant 'runtimeElements' capability io.tryp:splain_2.13.11:1.0.2 declares a library for use during runtime, packaged as a jar, and its dependencies declared externally:

• Incompatible because this component declares a component, compatible with Java 11 and the consumer needed a component, compatible with Java 8
• Other compatible attribute:

• Doesn't say anything about its target Java environment (preferred optimized for standard JVMs)

• Variant 'sourcesElements' capability io.tryp:splain_2.13.11:1.0.2 declares a component for use during runtime, and its dependencies declared externally:

• Incompatible because this component declares documentation and the consumer needed a library
• Other compatible attributes:

• Doesn't say anything about its target Java environment (preferred optimized for standard JVMs)
• Doesn't say anything about its target Java version (required compatibility with Java 8)
• Doesn't say anything about its elements (required them preferably in the form of class files)

我的问题是：

1. 为何splain 1.0.2被报告仅兼容Java 11，尽管已显式指定使用其他Java版本？
2. 如何从消费端临时禁用该兼容性检查？

1. 兼容性报告为Java 11的原因 #

仅设置ScalaCompile的targetCompatibility不足以让Gradle正确识别组件的Java兼容性属性。这个配置只是控制编译时生成的字节码版本，但Gradle发布组件时，还需要通过JavaPluginExtension的toolchain或者显式配置java组件的属性来声明兼容的Java版本。

从错误信息推断，splain的发布包中，Gradle自动推断出的兼容Java版本是11——这很可能是因为构建该插件时使用的JDK版本是11。Gradle在没有显式配置兼容性属性的情况下，会默认使用构建环境的JDK版本作为组件的兼容版本，忽略targetCompatibility的设置。

2. 消费端临时禁用兼容性检查 #

可以通过修改Gradle配置，针对splain插件的依赖调整兼容性规则：

方法1：针对特定依赖修正属性 #

在项目的build.gradle.kts中添加如下配置，强制将splain的目标JVM版本设置为8：

configurations.all {
    resolutionStrategy.eachDependency {
        if (requested.group == "io.tryp" && requested.name == "splain_2.13.11" && requested.version == "1.0.2") {
            attributes {
                attribute(TargetJvmVersion.TARGET_JVM_VERSION_ATTRIBUTE, 8)
            }
        }
    }
}

方法2：全局放宽检查（仅临时使用） #

如果需要临时绕过所有Java版本检查，可以添加：

configurations.all {
    attributes.attribute(TargetJvmVersion.TARGET_JVM_VERSION_ATTRIBUTE, 8)
}

或者直接指定依赖的能力选择：

configurations.all {
    resolutionStrategy.capabilitiesResolution.withCapability("io.tryp:splain_2.13.11") {
        select("io.tryp:splain_2.13.11:1.0.2")
    }
}

注意：全局禁用兼容性检查会带来潜在的运行风险，仅建议在临时调试时使用，长期来看最好推动插件官方修复其发布配置，正确声明兼容的Java版本。

内容的提问来源于stack exchange，提问作者tribbloid