CheckstyleExtension checkstyle = project.getExtensions().getByType(CheckstyleExtension.class);
        tasks.register("checkstyleApi", Checkstyle.class, task -> {
            task.source(extension.getDocumentedSource());
            // TODO: This is ugly
            task.setConfig(project.getResources().getText().fromFile(checkstyle.getConfigDirectory().file("checkstyle-api.xml")));

        languageVersion.set(JavaLanguageVersion.of(17))
      }
    }
  }

  tasks.withType<Checkstyle>().configureEach {
    exclude("**/CipherSuite.java")
  }

  val checkstyleConfig: Configuration by configurations.creating
  dependencies {
    checkstyleConfig(rootProject.libs.checkStyle) {
      isTransitive = false
    }
  }

  val androidSignature by configurations.creating

  <description>The effective model builder, with inheritance, profile activation, interpolation, ...</description>

  <properties>
    <!-- in: DefaultModelValidator, DefaultModelBuilder -->
    <checkstyle.violation.ignore>FileLength</checkstyle.violation.ignore>
  </properties>

  <dependencies>
    <dependency>
      <groupId>org.apache.maven</groupId>
      <artifactId>maven-api-annotations</artifactId>
    </dependency>

  // OkHttp requires Java 8+.
  jvmSignature(rootProject.libs.codehaus.signature.java18) { artifact { type = "signature" } }

  checkstyleConfig(rootProject.libs.checkStyle) {
    isTransitive = false
  }
}

// Animal Sniffer confirms we generally don't use APIs not on Java 8.
configure<AnimalSnifferExtension> {
  annotation = "okhttp3.internal.SuppressSignatureCheck"

plugin, so following best practices is relatively straightforward.  For core plugins in gradle/gradle, it's easy for an object to be created without applying its associated plugin. For instance, Spring has a plugin that uses the Checkstyle task directly without applying the Checkstyle plugin.

Until we can provide the same guarantees for core plugins, we need to be more conservative for existing classes and not follow best practices. This means conventions need to be set in both a plugin and the...

    // org.apache.maven:maven-plugin-api                -(PARENT)->
    // org.apache.maven:maven                           -(inherited REPORTING)->
    // org.apache.maven.plugins:maven-checkstyle-plugin -(DEPENDENCY)->
    // org.apache.maven:maven-plugin-api
    // In this case, both the verify and the report goals are called
    // in a different lifecycle. Though the compiler-plugin has a valid use case, although

        java.lang
        """.stripIndent()

        new File(projectDir, "build.gradle") << """
            plugins {
                id 'java'
                id 'checkstyle'
                id 'gradlebuild.documentation'
            }

            repositories {
                mavenCentral()
            }

            gradleDocumentation {
                javadocs {

    verifyComplexMessage(expected);
  }

  public void testCheckState_simple_success() {
    checkState(true);
  }

  public void testCheckState_simple_failure() {
    assertThrows(IllegalStateException.class, () -> checkState(false));
  }

  public void testCheckState_simpleMessage_success() {
    checkState(true, IGNORE_ME);
  }

  public void testCheckState_simpleMessage_failure() {

   */
  public final double pearsonsCorrelationCoefficient() {
    checkState(count() > 1);
    if (isNaN(sumOfProductsOfDeltas)) {
      return NaN;
    }
    double xSumOfSquaresOfDeltas = xStats.sumOfSquaresOfDeltas();
    double ySumOfSquaresOfDeltas = yStats.sumOfSquaresOfDeltas();
    checkState(xSumOfSquaresOfDeltas > 0.0);
    checkState(ySumOfSquaresOfDeltas > 0.0);

   */
  public double pearsonsCorrelationCoefficient() {
    checkState(count() > 1);
    if (isNaN(sumOfProductsOfDeltas)) {
      return NaN;
    }
    double xSumOfSquaresOfDeltas = xStats().sumOfSquaresOfDeltas();
    double ySumOfSquaresOfDeltas = yStats().sumOfSquaresOfDeltas();
    checkState(xSumOfSquaresOfDeltas > 0.0);
    checkState(ySumOfSquaresOfDeltas > 0.0);