gradle包含传递运行时依赖性作为编译依赖性

Question

I am expriencing a strange behavior in gradle dependency management, where project A references project B as compile dependency and project B references library C as runtime dependency. Now I can use classes from library C in my project A.

My question: (Why) is this a bug or a feature?

The problem can be reproduced with gradle 2.9 and 2.10 and the following minimal setup:

// settings.gradle
include ':A', ':B'

// build.gradle
allprojects {
    apply plugin: 'java'
    apply plugin: 'maven'

    repositories {
        mavenLocal()
        mavenCentral()
    }
}

project(':A') {
    dependencies {
        compile project(':B')
    }
}

project(':B') {
    dependencies {
        runtime "org.slf4j:slf4j-log4j12:1.7.13"
    }
}

As you can see, a gradle :A:dependencies shows

[...]

compile - Compile classpath for source set 'main'.
\--- project :B
     \--- org.slf4j:slf4j-log4j12:1.7.13
          +--- org.slf4j:slf4j-api:1.7.13
          \--- log4j:log4j:1.2.17
[...]

and using log4j is totally possible in java code residing in project A.

Answer 1

See this Q&A. If you don't specify a configuration, Gradle will choose the default configuration which extends from runtime . A quick fix is to use

compile project(path: ":B", configuration: "compile")

Answer 2

在Android库（aar）传递运行时依赖性的情况下，这从Gradle 5.0开始修复。