Gradle custom plugin depends on system task

Question

I hava a custom plugin called MyPlugin and it contains a custom task called MyTask . I want to make MyTask dependsOn compileJava . I tried to give MyTask.dependsOn(compileJava) , but it says Task called 'MyTask' is not existing . Is there any way to do it?

MyPlugin.java

public class MyPlugin implements Plugin<Project> {
    public static final String TASK_NAME = "MyTask";

    @Override
    public void apply(Project project) {
        project.getExtensions().create(TASK_NAME, MyExtension.class);
        project.getTasks().create(TASK_NAME, MyTask.class);
    }
}

MyTask.java

public class MyTask extends DefaultTask {
    private MyExtension extension;

    @TaskAction
    public void myTask() {
        Project project = getProject();
        extension = project.getExtensions().findByType(MyExtension.class);
        PropertyManager propertyManager = new PropertyManager(project, extension);
        propertyManager.setProperties();
        System.out.println(extension.getValue());
    }

MyExtension.java

public class MyExtension {
    private String value;

    public String getValue() {
        return value;
    }

    public void setValue(String value) {
        this.value = value;
    }
}

build.gradle

apply plugin: 'maven'
apply plugin: 'groovy'
apply plugin: 'java'
apply plugin: 'com.jfrog.bintray'

sourceCompatibility = 1.8

dependencies {
    testCompile group: 'junit', name: 'junit', version: '4.11'
    compile gradleApi()
}

repositories {
    mavenCentral()
}

buildscript {
    repositories {
        jcenter()
    }
    dependencies {
        classpath 'com.jfrog.bintray.gradle:gradle-bintray-plugin:1.4'
    }
}

task copyLibs(type: Copy) {
    from configurations.runtime
    into "$projectDir/libs"
}

MyTask.dependsOn(copyLibs)  //not working
MyTask.dependsOn(compileJava)   //not working

Answer 1

You have to use

tasks.MyTask.dependsOn(copyLibs) 
tasks.MyTask.dependsOn(compileJava)

because the task object you defined is not in the current scope like copyLibs. But you can access it via the tasks reference (see: https://docs.gradle.org/current/dsl/org.gradle.api.Project.html )

Answer 2

If you gradle plugin isapplied to a different gradle project, say projectA, your plugin adds a task called MyTask to projectA. The build.gradle you posted above is for the plugin-project and does not have a task called MyTask.

Answer 3

As far as I can see your task is called myTask , not MyTask . It was a typo in author's code.

UPDATE :

You don't apply your plugin so the task doesn't get created. And you cannot apply a plugin from a plugin's build.gradle . At least you cannot apply a version of the plugin being build. The best you can do is to apply a previously built version of the plugin that's stored in a Maven repo. But it doesn't look like a good idea.