+
If you are developing custom Gradle plugins for your project, `buildSrc` is a convenient place to house the plugin code.
This makes the plugins easily accessible within your project.

The `buildSrc` directory is treated as an <<composite_builds.adoc#composite_build_intro,included build>>.

For multi-project builds, there can be only one `buildSrc` directory, which must be in the root project directory.

        output.contains('system_property_available in buildSrc:                 true')
        output.contains('project_property_available in buildSrc:                false')
        output.contains('overridden_by_includedBuild in buildSrc:               null')
        output.contains('system_property_available in included buildSrc:        true')
        output.contains('project_property_available in included buildSrc:       false')

     */
    IncludedBuildState addImplicitIncludedBuild(BuildDefinition buildDefinition);

    /**
     * Locates the buildSrc build for the given build, if present. Returns null if the given build does not have an associated buildSrc build.
     */
    @Nullable
    StandAloneNestedBuild getBuildSrcNestedBuild(BuildState owner);

    /**
     * Creates a new standalone nested build tree.

def buildOs = 'linux'
def buildJdk = '17'
def buildMvn = '3.8.x'
def runITsOses = ['linux']
def runITsJdks = ['17', '21']
def runITsMvn = '3.8.x'
def runITscommand = "mvn clean install -Prun-its,embedded -B -U -V" // -DmavenDistro=... -Dmaven.test.failure.ignore=true
def tests

try {

def osNode = jenkinsEnv.labelForOS(buildOs)
node(jenkinsEnv.nodeSelection(osNode)) {

 *
 * It is effectively the root dir of a build.
 * That is, two builds with the same root dir share the same workspace.
 *
 * In practice, this generally maps to what users would think of as “checkout” of a project.
 * Builds of the same checkout over time will share the same workspace ID.
 *
 * This ID is persisted in the root build's project cache dir.
 * If this cache directory is destroyed, a new ID will be issued.
 */

    }

    /**
     * the `buildSrc` directory behaves like an included build. As such, it may have its own settings,
     * so repositories declared in the main build shouldn't be visible to buildSrc.
     */
    def "repositories declared in settings shouldn't be used to resolve dependencies in buildSrc"() {
        repository {
            'org:module:1.0'()
        }

            broken!
        """
        buildA.buildFile << """
            task other {
                dependsOn configurations.compileClasspath
            }
            classes.dependsOn other
        """
        buildA.file("src/main/java/A.java") << """
            class A { }
        """

        when:
        fails(buildA, "assemble")

        then:

    @Rule BlockingHttpServer server = new BlockingHttpServer()

    def "works when number of included builds exceeds max-workers --max-workers=#maxWorkers"() {
        def totalIncludedBuilds = 5*maxWorkers
        buildA.buildFile << """
            task delegate {
                dependsOn gradle.includedBuilds*.task(":someTask")
            }
        """

structuring-builds-4.png...

/**
 * A listener that is notified when a root build is started and completed. No more than one root build may run at a given time.
 *
 * A root build may contain zero or more nested builds, such as `buildSrc` or included builds.
 *
 * This listener type is available to services from build tree up to global services.
 */
@EventScope(Scope.BuildTree.class)
@StatefulListener
public interface RootBuildLifecycleListener {