The build session state also includes "cross session" state that is shared with any "nested" sessions that need to be created.
This only happens when the `GradleBuild` task is used. You can mostly ignore the distinction between "cross session" and "build session" state.

### Build tree state

"Build tree" is another name for the build definition.

    Otherwise, TeamCity complains "Can't find the previous revision, please commit current settings first".
  - If anything bad happens, feel free to delete the project you created and retry (you may need to apply `Synchronization disabled` before deleting it).  
    
If no errors, your new pipeline will be displayed on TeamCity web UI:

```
Gradle

        val subProjectFolders = subprojectRoots.map { it.listFiles(File::isDirectory).asList() }.flatten().filter { dir ->
            // filter out the directories that have only a `build` subdirectory - this usually happens after branch switching
            dir.listFiles { _: File, name: String -> name != "build" }!!.isNotEmpty()
        }
        assertFalse(subProjectFolders.isEmpty())
        return subProjectFolders
    }