[zbentley]

Hope it helps!

One clarification: by "check for deletions" I didn't mean that you need to read back through the filesystem; you can check for deletions for free using fstat(2)'s result. The number of hard links to a file descriptor's underlying description returned by fstat includes the "existential" hard link of the file itself, and drops to zero when the file's deleted and the open handle is an orphan:

    import os
    import time
    from threading import Thread, Event

    f = '/tmp/foo.test'
    ev = Event()
    Thread(target=lambda: ev.wait() and os.unlink(f), daemon=True).start()

    with open(f, 'w+') as fh:
        print("before delete:", os.fstat(fh.fileno()).st_nlink)
        ev.set()
        time.sleep(1)
        print("after delete:", os.fstat(fh.fileno()).st_nlink)

[russellthehippo]

Ha. Great callout. Will inspect further