Resolving a Configuration does not resolve the "parent" configurations that it extendsFrom

Help/Discuss
1

This is sort of an extension of what I was running into in Configuration and transitive dependency management by extension . I was trying an approach that uses beforeResolve instead and copies the correct dependencies around into other configurations, but my tests were failing and I was confused as to why.

Should configurations that are extended from be resolved when a configuration extending it is resolved? My expectation was “yes”, but the docs don’t say what should happen, or even what extendsFrom means. This was surprising to me.

Here is a short example:

wrapper.gradleVersion = '4.2.1'

configurations {
  mkparent
  mk.extendsFrom(mkparent)
}

repositories {
  jcenter()
}

dependencies {
  mkparent group: 'junit', name: 'junit', version: '4.12'
  mk group: 'com.google.guava', name: 'guava', version: '23.0'

}

configurations.mkparent.incoming.beforeResolve {
  println('mkparent: BEFORE RESOLVE')
}

configurations.mk.incoming.beforeResolve { resolvableDependencies ->
  println 'mk: BEFORE RESOLVE'
}

tasks.create("show") {
  group = 'TESTING'
  doFirst {
    final mk = configurations.mk
    [
      mk
    ].each {
      println("Configuration: ${it.name}")
      it.resolvedConfiguration.firstLevelModuleDependencies.each {
        println("  First level: $it")
      }
      println()
      it.resolvedConfiguration.resolvedArtifacts.each {
        println("  Resolved: $it")
      }
      println()
      println('-' * 100)
      println()
    }
    println("mkparent State=${configurations.mkparent.state}")
    println("mk State=${configurations.mk.state}")
  }
}

And the output shows that mkparent is not resolved:

Configuration: mk
mk: BEFORE RESOLVE
  First level: com.google.guava:guava:23.0;default
  First level: junit:junit:4.12;default

  Resolved: guava.jar (com.google.guava:guava:23.0)
  Resolved: junit.jar (junit:junit:4.12)
  Resolved: jsr305.jar (com.google.code.findbugs:jsr305:1.3.9)
  Resolved: error_prone_annotations.jar (com.google.errorprone:error_prone_annotations:2.0.18)
  Resolved: j2objc-annotations.jar (com.google.j2objc:j2objc-annotations:1.1)
  Resolved: animal-sniffer-annotations.jar (org.codehaus.mojo:animal-sniffer-annotations:1.14)
  Resolved: hamcrest-core.jar (org.hamcrest:hamcrest-core:1.3)

----------------------------------------------------------------------------------------------------

mkparent State=UNRESOLVED
mk State=RESOLVED
2

No, they are not resolved. The extending configuration just inherits all the dependency declarations from the one it extends. It then resolves them all together.