如何将 gradle 子项目源目录添加到配置/类路径

Question

I need to add a source path of a subproject to a Gradle configuration used to run the GWT code server via JavaExec task.

All my tries fail whether nothing is added or the build fails. I am quite new to Gradle and it seems I miss some crucial step.

Here's how a configuration is created and used:

configurations {
    gwtCodeServer
}

task runCodeServer(type: JavaExec) {
    classpath = configurations.gwtCodeServer
    doFirst { 
      classpath.each { println it} 

      // prints correct path in brackets: [C:/fullpath_to_subproject/src/main/java]
      println files( project(':subproject.name').sourceSets.main.java.srcDirs ).files
    }
}

and here's how I populate the configuration:

dependencies {
    gwtCodeServer files(project.sourceSets.main.java.srcDirs) // OK
    gwtCodeServer files(project.sourceSets.main.resources.srcDirs) // OK
    gwtCodeServer files('C:/opt/gwt-2.9.0/gwt-codeserver.jar') // OK

    // OK (according to println classpath) but only for hardcoded path
    gwtCodeServer files('C:/fullpath_to_subproject/src/main/java') 

    // KO - adds nothing according to println classpath above
    gwtCodeServer files(project(':subproject.name').sourceSets.main.java.srcDirs) 

    // KO FAILS with 'Cannot convert the provided notation to an object of type Dependency'
    // even when println shows correct path (probably via .toString())
    gwtCodeServer files(project(':subproject.name').sourceSets.main.java.srcDirs).files 

}

Answer 1

I found the reason:

In my project configuration the subprojects are initialized after computing of the dependencies of the main project, on next steps.

As a result, in dependencies {} block, project(':subproject.name').sourceSets.main.java.srcDirs returns same path as of main project, project.sourceSets.main.java.srcDirs

in runCodeServer.doFirst the subproject is already initialized so its source path was printed correctly there.

Thus I will have to add all subproject source dirs in runCodeServer.doFirst closure instead of dependency {}