get() = extensions.extraProperties


/**
 * Provides property delegate for typed access to extra properties.
 */
operator fun ExtraPropertiesExtension.provideDelegate(receiver: Any?, property: KProperty<*>): MutablePropertyDelegate =
    if (property.returnType.isMarkedNullable) NullableExtraPropertyDelegate(this, property.name)
    else NonNullExtraPropertyDelegate(this, property.name)


private
class NonNullExtraPropertyDelegate(

        property.set("12")
        return property
    }

    Property<String> propertyWithCompletedProducer() {
        def task = Mock(Task)
        def state = Mock(TaskState)
        _ * task.toString() >> "<task>"
        _ * task.state >> state
        _ * state.executed >> true
        def owner = Stub(ModelObject)
        _ * owner.taskThatOwnsThisObject >> task

            tasks.create("thing", MyTask) {
                println("property = \$count")
                count = 12
            }
        """

        when:
        succeeds("thing")

        then:
        outputContains("property = task ':thing' property 'count'")
        outputContains("count = 12")
    }

    def "reports failure to query managed Property<T> with no value"() {
        given:
        buildFile << """

        "System.properties['some.property']"                   | _
        "System.getProperties().get('some.property')"          | _
        "getProperties().get('some.property')"                 | _
        "System.getProperty('some.property')"                  | _
        "getProperty('some.property')"                         | _
        "System.getProperty('some.property', 'default.value')" | _
        "getProperty('some.property', 'default.value')"        | _

import org.gradle.api.provider.MapProperty;
import org.gradle.api.provider.Property;

public interface CheckstyleActionParameters extends AntWorkParameters {
    RegularFileProperty getConfig();

    ConfigurableFileCollection getSource();

    Property<Integer> getMaxErrors();

    Property<Integer> getMaxWarnings();

    Property<Boolean> getIgnoreFailures();

    DirectoryProperty getConfigDirectory();

        "System.getProperties().get(\"some.property\")"            | _
        "System.getProperty(\"some.property\")"                    | _
        "System.getProperty(\"some.property\", \"default.value\")" | _
        "System.setProperty(\"some.property\", \"new.value\")"     | _
        "System.clearProperty(\"some.property\")"                  | _
    }

    def "setProperties is instrumented in Java"() {

        when:
        configurationCacheRun("-Dsome.property.1=1", "-Dsome.property.2=2", "print")

        then:
        configurationCache.assertStateStored()
        outputContains("Configuration: some.property.1 = 0")
        outputContains("Configuration: some.property.2 = 2")

        when:
        configurationCacheRun("-Dsome.property.1=-1", "-Dsome.property.2=2", "print")

        then:

    /**
     * Adds an element to the property value.
     *
     * <p>The given provider will be queried when the value of this property is queried.
     *
     * <p>
     * When invoked on a property with no value, this method first sets the value
     * of the property to its current convention value, if set, or an empty collection.
     * </p>
     * <p>Even if the given provider has no value, after this method is invoked,

        if (getterMethod == null) {
            throw new NoSuchPropertyException(String.format("Could not find getter method for property '%s' on class %s.", property, target.getSimpleName()));
        }
        return new GetterMethodBackedPropertyAccessor<T, F>(property, returnType, getterMethod);
    }

    /**
     * Locates the property with the given name as a readable property. Searches only public properties.
     *

        "${Property.name}<String>"            | "objects.property(String); v.set('abc')"              | "objects.property(String); v.set('123')"                     | "Type 'SomeTask': property 'v' of mutable type 'org.gradle.api.provider.Property' is writable. Properties of type 'org.gradle.api.provider.Property' are already mutable. Possible solution: Remove the 'setV' method. ${learnAt("validation_problems",...