Gradle standalone plugin unknown property when loaded from github repository - github

Question

I've created a simple standalone Gradle plugin in Java and a Maven repository on GitHub for publishing the plugin. Everything works fine except retrieving project properties that should be available with the plugin. When I apply the plugin in another Gradle project, it can't find those properties.
It happens only when the plugin is loaded from the remote repository on GitHub. When loaded from a local repository, it works. Can the plugin implementation be somehow set to provide properties even from a remote repository? Or is this some GitHub feature that can't be hacked?
Details follow:
My build.gradle in the another project looks something like this:
buildscript {
repositories {
maven {
url "GITHUB_REPO_URL"
}
}
dependencies {
classpath "custom_plugin_group:custom_plugin:1.0"
}
}
apply plugin: "custom_plugin"
task propertyTest {
doLast {
println project.customProperty
}
}
When I try to run the the task propertyTest, it fails complaining that "Could not get unknown property 'customProperty' for root project 'another_project' of type org.gradle.api.Project."
I'm creating the property in the method apply in the main plugin class. I have tried following three approaches:
// First approach - adding a simple value to extensions
public class CustomPlugin implements Plugin<Project> {
#Override
public void apply(Project project) {
project.getExtensions().add("customProperty", "Custom property value");
}
}
// Second approach - setting extra property to extensions
public class CustomPlugin implements Plugin<Project> {
#Override
public void apply(Project project) {
project.getExtensions().getExtraProperties().set("customProperty", "Custom property value");
}
}
// Third approach - adding a property instance to extensions
public class CustomPlugin implements Plugin<Project> {
#Override
public void apply(Project project) {
Property<String> customProperty = project.getObjects().property(String.class);
customProperty.set("Custom property value");
project.getExtensions().add("customProperty ", customProperty);
}
}

Answer 1

For creating extensions for your Gradle plugin you need create POJO class with fields:
class YourExtension {
String customProperty
}
And then create extension in your plugin class:
public class CustomPlugin implements Plugin<Project> {
#Override
public void apply(Project project) {
project.getExtensions().create("extensionName", YourExtension.class);
}
}
Now you can use extension in build.gradle file:
extensionName {
customProperty = "value"
}