build_tree --> build1
  
  project1["root project"]
  build1 --> project1
  
  project2["project"]
  build1 --> project2
  
  build2["included build"]
  build_tree --> build2
  
  project3["root project"]
  build2 --> project3
  
  project4["project"]
  build2 --> project4

```

### Build process state

import java.io.ByteArrayOutputStream
import java.io.File


/**
 * `dir / "sub"` is the same as `dir.resolve("sub")`.
 *
 * @see [File.resolve]
 */
operator fun File.div(child: String): File =
    resolve(child)


fun Project.execAndGetStdout(workingDir: File, ignoreExitValue: Boolean, vararg args: String): String {
    val out = ByteArrayOutputStream()
    exec {
        isIgnoreExitValue = ignoreExitValue

                    if (seenTopLevelPackages.add(packageName) && nameFilter(packageName)) {
                        yield(analysisSession.firSymbolBuilder.createPackageSymbol(FqName.ROOT.child(packageName)))
                    }
                }
            }
        }
    }

    override fun getPossibleCallableNames(): Set<Name> = withValidityAssertion {

      accumulatorBitCount -= 8
      val childIndex = (code ushr accumulatorBitCount) and 0xff
      val children = node.children!!
      var child = children[childIndex]
      if (child == null) {
        child = Node()
        children[childIndex] = child
      }
      node = child
    }

    val shift = 8 - accumulatorBitCount
    val start = (code shl shift) and 0xff
    val end = 1 shl shift

     which combines profile activation+injection and inheritance assembly from parents,

   * known limitations are notably that:

     1. plugin goal execution in a child is usually simply appended (at end): you can't try to insert in the middle of pre-existing inherited executions,

     2. append happens at plugin level first, then goal level, independently from phases.

        sequence {
            analysisSession.useSitePackageProvider.getSubPackageFqNames(fqName, analysisSession.targetPlatform, nameFilter).forEach {
                yield(analysisSession.firSymbolBuilder.createPackageSymbol(fqName.child(it)))
            }
        }
    }