Transitive dependency resolution for languages no supported yet

Help/Discuss
1

I try to get Gradle 2.7 to resolve dependencies for a language that is not supported yet. So I use only very basic constructs. Dependencies are fetched, but not transitive dependencies, I need some help. I demonstrate this with three projects: leaf, tree, and forest:

The leaf project build.gradle:

plugins {
  id 'base'
  id 'maven-publish'
}

group = 'org.martin'
version = '0.1.0'

task sourceZip(type: Zip) {
  from 'src'
}

publishing {
  publications {
    source(MavenPublication) {
      artifact(sourceZip) {
      }
    }
  }
}

publishing {
  repositories {
    maven {
      url '/tmp/localRepository'
    }
  }
}

I publish this project with: ./gradlew publish

Then the tree project, which lists the leaf artifact as a dependency in its build.gradle:

plugins {
  id 'base'
  id 'maven-publish'
}

repositories {
  maven {
    url '/tmp/localRepository'
  }
}

configurations {
  srcCode
}

dependencies {
  srcCode 'org.martin:leaf:0.1.0'
}

group = 'org.martin'
version = '0.1.0'

task sourceZip(type: Zip) {
  from 'src'
}

publishing {
  publications {
    source(MavenPublication) {
      artifact(sourceZip) {
      }
    }
  }
  repositories {
    maven {
      url '/tmp/localRepository'
    }
  }
}

I publish this project’s artifact with: ./gradlew publish

Lastly, the forest project build.gradle file which lists the tree artifact as a dependency:

plugins {
  id 'base'
  id 'maven-publish'
}

repositories {
  maven {
    url '/tmp/localRepository'
  }
}

configurations {
  srcCode
}

dependencies {
  srcCode 'org.martin:tree:0.1.0'
}

When I type ./gradlew dependencies in the forest project, it only lists the first dependency, and it is missing the transitive dependency. I expect to see both the leaf and the tree dependencies:

:dependencies

------------------------------------------------------------
Root project
------------------------------------------------------------

archives - Configuration for archive artifacts.
No dependencies

default - Configuration for default artifacts.
No dependencies

srcCode
\--- org.martin:tree:0.1.0

BUILD SUCCESSFUL

Q1: Is it possible to make dependency resolution work if the language is not supported yet?
Q2: How can I change my example to make it work?
Q3: I have read that if I add extensions, it disables dependency resolution, but if I add a classifier, will it disable dependency resolution?

Thanks.