def do_run()

in scripts/doctor.py [0:0]

• 34 lines of code
• 22 McCabe index (conditional complexity)

def do_run(tasks, run_fn):
  dones = set()
  starteds = set()
  failed = False
  event_queue = queue.Queue()

  while True:
    if len(dones) >= len(tasks):
      break
    if failed and len(dones) >= len(starteds):
      break

    if not failed:
      # Identify tasks that have become eligible (0 prerequisites)
      # and execute them. Note that identified eligible tasks might be
      # already running and need to be filtered out. This is because we
      # handle one task event at a time.
      prereq_counts = [(task.name, len(task.prerequisites.difference(dones)))
                       for task in tasks.values()
                       if task.name not in dones]
      prereq_counts.sort(key=lambda name_count: name_count[1], reverse=True)
      candidate_names = [name for (name, count) in prereq_counts if count == 0]
      if not candidate_names:
        raise BadPrerequisitesException('Found a cycle in {}'.format(
            [name for (name, _) in prereq_counts]))
      for name in [c for c in candidate_names if c not in starteds]:
        starteds.add(name)
        run_fn(tasks[name], event_queue)

    # Wait for and process the next task event.
    task_event = event_queue.get()
    if task_event.name:
      dones.add(task_event.name)
      if not task_event.success:
        failed = True
      if task_event.message:
        print('\n{}\n\n===='.format(task_event.message.strip()))