Invalid classpath publish/ export dependency /ouat-contract. Project entries not supported

I am trying create an Gradle multi project similar to this structure

ouat-services
  - ouat-contract
  - ouat-servicesImpl (web project)

I followed the eclipse example and define my ouat-services settings.gradle as

include "ouat-contract", "ouat-servicesImpl"

In my ouat-servicesImpl build-gradle I define

dependencies {
  compile project(':ouat-contract')
}

My problem starts when I try apply war plug-in in ouat-servicesImpl, I receive the following message in eclipse problem view:

Invalid classpath publish/ export dependency /ouat-contract. Project entries not supported

My ouat-services build.gradle

configure(subprojects) {

  apply plugin: 'com.github.ben-manes.versions'
  apply plugin: 'eclipse'
  apply plugin: 'java'

  version = '1.0'

  sourceCompatibility = 1.8
  targetCompatibility = 1.8

  def defaultEncoding = 'UTF-8'
  [compileJava, compileTestJava]*.options*.encoding = defaultEncoding

  repositories {

    jcenter()
    mavenLocal()
    mavenCentral()
  }

  jar {
    manifest.attributes provider: 'Company'
  }
}

configure(project(':ouat-servicesImpl')) {

  apply plugin: 'checkstyle'
  apply plugin: 'eclipse-wtp'
  apply plugin: 'findbugs'
  apply plugin: 'jacoco'
  //apply plugin: 'jetty'
  apply plugin: 'pmd'
  apply plugin: 'war'
}

buildscript {

  repositories {

    jcenter()
    mavenCentral()
    mavenLocal()
  }

  dependencies {
    classpath 'com.github.ben-manes:gradle-versions-plugin:0.10.1'
  }
}

My ouat-servicesImpl build gradle was changed to:

dependencies {

  compile project(':ouat-contract')

  cxfArtifacts.each { artifact ->
    compile "org.apache.cxf:$artifact:$cxfVersion"
  }

  springArtifacts.each { artifact ->
    compile "org.springframework:$artifact:$springVersion"
  }

  testCompile "org.testng:testng:$testNGVersion"
  testCompile "org.hamcrest:hamcrest-all:$hamcrestVersion"
  testCompile "org.springframework:spring-test:$springVersion"

  //WAR PLUGIN
  providedCompile "javax.servlet:javax.servlet-api:$servletAPIVersion"
  runtime "javax.servlet:jstl:$jstlVersion"
}

Is this an eclipse plug-in problem or I am doing something wrong?

Solution

I've also run into this problem long time ago. It really seems to be the problem related to the Eclipse plugin included in "Gradle IDE Pack" (as it works from the command line without problems). My setup is probably way more complex than Yours (I'm including modules from one top-level gradle project into another top-level gradle project), but to overcome this specific error

Invalid classpath publish/ export dependency /my-project. Project entries not supported

... i excluded project dependency if some specific gradle property was missing:

if(project.hasProperty("myProjectRefAddedFromIDE")) {
    println "NB! Build script started with property 'myProjectRefAddedFromIDE' - expecting that this project in IDE is configured to add the direct reference to my-project"
} else {
    compile project(':my-project')
}

And to add the property "myProjectRefAddedFromIDE" only from IDE, i have configured eclipse plugin as follows: Window -> Preferences -> Gradle -> Arguments -> Program arguments -> Use: ´-PmyProjectRefAddedFromIDE´

Just a warning: this will probably work for you, but there might be some other problem with Your setup, as for simple multi-module project (that doesn't include modules form another multi-module project) I don't have to use this workaround.