// The version in sub-locations may be smaller than the version we queried at the root when using a `StoringAction`.
        if (versionBefore >= versionAfter) {
            updateRootUnderLock(root -> updateNotifyingListeners(diffListener -> root.store(absolutePath, snapshot, diffListener)));
        } else {

public class TestVirtualFileSystem extends AbstractVirtualFileSystem {

    public TestVirtualFileSystem(SnapshotHierarchy root) {
        super(root);
    }

    @Override
    protected SnapshotHierarchy updateNotifyingListeners(UpdateFunction updateFunction) {
        return updateFunction.update(SnapshotHierarchy.NodeDiffListener.NOOP);
    }

    public void setRoot(SnapshotHierarchy newRoot) {

    def vfs = new AbstractVirtualFileSystem(DefaultSnapshotHierarchy.empty(CaseSensitivity.CASE_SENSITIVE)) {
        @Override
        protected SnapshotHierarchy updateNotifyingListeners(AbstractVirtualFileSystem.UpdateFunction updateFunction) {
            return updateFunction.update(SnapshotHierarchy.NodeDiffListener.NOOP)
        }
    }

    public WatchingNotSupportedVirtualFileSystem(SnapshotHierarchy root) {
        super(root);
    }

    @Override
    protected SnapshotHierarchy updateNotifyingListeners(UpdateFunction updateFunction) {
        return updateFunction.update(SnapshotHierarchy.NodeDiffListener.NOOP);
    }

    @Override
    public boolean afterBuildStarted(
        WatchMode watchMode,

        protected CustomVirtualFileSystem(SnapshotHierarchy root) {
            super(root);
        }

        @Override
        protected SnapshotHierarchy updateNotifyingListeners(UpdateFunction updateFunction) {
            return updateFunction.update(SnapshotHierarchy.NodeDiffListener.NOOP);
        }
    }

        this.watchableFileSystemDetector = watchableFileSystemDetector;
        this.fileChangeListeners = fileChangeListeners;
    }

    @Override
    protected SnapshotHierarchy updateNotifyingListeners(UpdateFunction updateFunction) {
        if (watchRegistry == null) {
            return updateFunction.update(SnapshotHierarchy.NodeDiffListener.NOOP);
        } else {

    FileWatcherUpdater updater
    def virtualFileSystem = new TestVirtualFileSystem(DefaultSnapshotHierarchy.empty(CaseSensitivity.CASE_SENSITIVE)) {
        @Override
        protected SnapshotHierarchy updateNotifyingListeners(AbstractVirtualFileSystem.UpdateFunction updateFunction) {
            def diffListener = new SnapshotCollectingDiffListener()
            def newRoot = updateFunction.update(diffListener)