Reentrance checking coroutine Mutex

gistfile1.kt

// https://github.com/Kotlin/kotlinx.coroutines/issues/3626#issuecomment-1451115356
// https://github.com/Kotlin/kotlinx.coroutines/issues/3626#issuecomment-1452820863

suspend fun <ReturnT> Mutex.checkedWithLock(
  block: suspend () -> ReturnT
): ReturnT {
  val element = LockedMutexesElement(this).key
  check (currentCoroutineContext()[element] == null) {
    "Reentered Mutex"
  }
  
  return withContext(element) { withLock { block() } }
}

private data class LockedMutexesElement(val mutex: Mutex) :
  CoroutineContext.Element, CoroutineContext.Key<LockedMutexesElement> {
  override val key = this
}