task.getInputEncoding().convention(Charset.defaultCharset().name());
            task.getOutputEncoding().convention(Charset.defaultCharset().name());

            task.getMarkdownFile().convention(extension.getReleaseNotes().getMarkdownFile());
            task.getDestinationFile().convention(extension.getStagingRoot().file("release-notes/raw.html"));
        });

            task.getVersion().convention(project.provider(() -> project.getVersion().toString()));
            task.getSourceFile().convention(dslDocbook.flatMap(AssembleDslDocTask::getDestFile));
            task.getLinksFile().convention(dslDocbook.flatMap(AssembleDslDocTask::getLinksFile));

            task.getDsldocUrl().convention("../dsl");
            task.getJavadocUrl().convention("../javadoc");

            userManual.getRoot().convention(extension.getSourceRoot().dir("userguide"));
            userManual.getStagingRoot().convention(extension.getStagingRoot().dir("usermanual"));
            // TODO: These should be generated too
            userManual.getSnippets().convention(layout.getProjectDirectory().dir("src/snippets"));
            userManual.getSamples().convention(layout.getProjectDirectory().dir("src/samples"));

When defining conventions for a property, there are largely three approaches:
1. Do not set a convention at all
2. Set a convention in a plugin
3. Set a convention in a constructor

Most properties should have a convention set, so (1) can be treated as a rare case where a value must be provided by a user.

    public JapicmpTask() {
        getFailOnModification().convention(false);
        getFailOnSourceIncompatibility().convention(false);
        getIgnoreMissingClasses().convention(false);
        getIncludeSynthetic().convention(false);
        getOnlyBinaryIncompatibleModified().convention(false);
        getOnlyModified().convention(false);
        getAccessModifier().convention("public");

plugins {
    java
    id("gradlebuild.dependency-modules")
}

extensions.create<IntegrationTestExtension>("integTest").apply {
    usesJavadocCodeSnippets.convention(false)
    testJvmXmx.convention("512m")
}

val sourceSet = addSourceSet(TestType.INTEGRATION)
addDependenciesAndConfigurations(TestType.INTEGRATION.prefix)
createTasks(sourceSet, TestType.INTEGRATION)

            task.into(extension.getDocumentationRenderedRoot());
        });

        extension.getSourceRoot().convention(layout.getProjectDirectory().dir("src/docs"));
        extension.getDocumentationRenderedRoot().convention(layout.getBuildDirectory().dir("docs"));
        extension.getStagingRoot().convention(layout.getBuildDirectory().dir("working"));

        ConfigurableFileTree css = objects.fileTree();

    @get:Input
    abstract val excludes: ListProperty<String>

    @get:Input
    abstract val includes: ListProperty<String>

    init {
        excludes.convention(DEFAULT_EXCLUDES)
        includes.convention(DEFAULT_INCLUDES)
    }

    @TaskAction
    fun generate() {
        IoActions.writeTextFile(outputFile.asFile.get(), object : ErroringAction<BufferedWriter>() {

      BundleTaskExtension::class.java,
      jarTask,
    )
  bundleExtension.run {
    setClasspath(osgi.compileClasspath + sourceSets["main"].compileClasspath)
    bnd(*bndProperties)
  }
  // Call the convention when the task has finished, to modify the jar to contain OSGi metadata.
  jarTask.doLast {
    bundleExtension.buildAction().execute(this)
  }
}

fun Project.applyOsgiMultiplatform(vararg bndProperties: String) {

# Default to Routes in the root package (and `conf/routes`)
# application.router=my.application.Routes

# Database configuration
# ~~~~~
# You can declare as many datasources as you want.
# By convention, the default datasource is named `default`
#
# db.default.driver=org.h2.Driver
# db.default.url="jdbc:h2:mem:play"
# db.default.user=sa
# db.default.password=""
#