warning actor-cycle

What it means#

A msg may wait for another actor, but if actor A waits for B while B waits for A, neither message can complete (§8.8). The analyzer reports possible cycles as a warning; it is configurable in [lint].

Example#

actor Left {
  var right: ActorRef<Right>
  msg ping() -> i32 { right.pong() }      // <- actor-cycle
}

actor Right {
  var left: ActorRef<Left>
  msg pong() -> i32 { left.ping() }
}

actor-cycle

How to fix#

actor Left {
  var right: ActorRef<Right>
  msg ping() -> i32 { right.pong() }
}

actor Right {
  msg pong() -> i32 { 1 }
}

Break the cycle: make one direction fire-and-forget (~>), return without waiting, or move the shared logic into a third actor.

See also#

• task-reuse
• blocking-in-task