fix: do not panic on TestOutputPipe::flush when receiver dropped (d…

…enoland#14560)

cli/tools/test.rs

@@ -1622,13 +1622,16 @@ impl TestOutputPipe {
  // We want to wake up the other thread and have it respond back
  // that it's done clearing out its pipe before returning.
  let (sender, receiver) = std::sync::mpsc::channel();
- self.state.lock().replace(sender);
+ if let Some(sender) = self.state.lock().replace(sender) {
+ let _ = sender.send(()); // just in case
+ }
  // Bit of a hack to send a zero width space in order to wake
  // the thread up. It seems that sending zero bytes here does
  // not work on windows.
  self.writer.write_all(ZERO_WIDTH_SPACE.as_bytes()).unwrap();
  self.writer.flush().unwrap();
- receiver.recv().unwrap();
+ // ignore the error as it might have been picked up and closed
+ let _ = receiver.recv();
  }
 
  pub fn as_file(&self) -> std::fs::File {