An improper way to share build logic between subprojects is _cross-project configuration_ via the link:{javadocPath}//org/gradle/api/Project.html#subprojects-groovy.lang.Closure-[`subprojects {}`] and link:{javadocPath}/org/gradle/api/Project.html#allprojects-groovy.lang.Closure-[`allprojects {}`] DSL constructs.

TIP:  Avoid using `subprojects {}` and `allprojects {}`.

```

Note that the samples are also used in `samples` subproject, see [`@UsesSample`](https://github.com/gradle/gradle/blob/9ade1a05427aaf04c976a0e85814b44b3435f9f9/subprojects/internal-integ-testing/src/main/groovy/org/gradle/integtests/fixtures/UsesSample.java#L25) and [`Sample`](https://github.com/gradle/gradle/blob/903c5f2cee88c9768077d46025eaafdf65862fc8/subprojects/internal-integ-testing/src/main/groovy/org/gradle/integtests/fixtures/Sample.java#L37).

        buildTestFixture.singleProjectBuild(projectName, cl)
    }

    def multiProjectBuild(String projectName, List<String> subprojects, @DelegatesTo(BuildTestFile) Closure cl = {}) {
        buildTestFixture.multiProjectBuild(projectName, subprojects, cl)
    }

        steps {
            script {
                // Because we exclude tests in `distributions-integ-tests` below, `@Flaky` won't work in that subproject.
                // Here we check the existence of `@Flaky` annotation to make sure nobody use that annotation in `distributions-integ-tests` subproject.
                name = "MAKE_SURE_NO_@FLAKY_IN_DISTRIBUTIONS_INTEG_TESTS"
                executionMode = BuildStep.ExecutionMode.ALWAYS

    @IntegrationTestTimeout(value = 60, onlyIf = { GradleContextualExecuter.embedded })
    def "can query dependencies with configure on demand enabled"() {
        def subprojects = ["a", "b"]
        multiProjectBuild("outputRegistry", subprojects)
        subprojects.each { projectName ->
            file("${projectName}/build.gradle") << """
                plugins {
                    id("java-library")
                }

        subproject("base-asm")
        subproject("base-services")
        subproject("build-configuration")
        subproject("build-operations")
        subproject("build-option")
        subproject("build-process-services")
        subproject("build-profile")
        subproject("build-state")
        subproject("cli")
        subproject("client-services")
        subproject("concurrent")
        subproject("daemon-main")

        buildType(stagePasses)
        subProject(stageProject)

        prevStage = stage
        previousPerformanceTestPasses.addAll(stageProject.performanceTests)
    }

    buildType(GitHubMergeQueueCheckPass(model))

    buildTypesOrder = buildTypes
    subProjectsOrder = subProjects

    cleanupRule(
        historyDays = 14,
        artifactsDays = 7,

====
include::sample[dir="snippets/plugins/multiproject/kotlin", files="settings.gradle.kts[tags=include-subprojects];build.gradle.kts[tags=plugins-on-subprojects];hello-a/build.gradle.kts[];hello-b/build.gradle.kts[];goodbye-c/build.gradle.kts[]"]

        }

        override fun subprojects(action: Action<in Project>) {
            delegate.subprojects(referrer, action)
        }

        override fun subprojects(configureClosure: Closure<*>) {
            delegate.subprojects(referrer, ConfigureUtil.configureUsing(configureClosure))
        }

        override fun subprojects(referrer: ProjectInternal, configureAction: Action<in Project>) {

<7> The project's <<settings_file_basics.adoc#sec:settings_file_script, settings file>> where the list of subprojects is defined.
<8> Usually, a project is organized into one or multiple subprojects.
<9> Each subproject has its own Gradle build script.

[[dir:project_root:cache_cleanup]]
=== Project cache cleanup