pyuv: Assertion `loop->watchers[w->fd] == w' failed

The following code will abort pyuv by triggering the assertion:

src/unix/core.c:651: uv__io_stop: Assertion loop->watchers[w->fd] == w’ failed.`.

According to the libuv docs it is safe to close an FD after you stop() the poll handle. But even if it isn’t safe, I think pyuv should not abort the program. In case of a programming error, it should raise an exception.

import os
import pyuv

def on_write(handle, events, errno):
    pass

loop = pyuv.Loop.default_loop()
r1, w1 = os.pipe()
poll1 = pyuv.Poll(loop, w1)
poll1.start(pyuv.UV_WRITABLE, on_write)
loop.run_once()  # -> pipe is writable
poll1.stop()
os.close(r1); os.close(w1)
# libuv docs tell it's safe to close the FD after stop()

r2, w2 = os.pipe()
assert w1 == w2, 'Try again'
poll2 = pyuv.Poll(loop, w2)
poll2.start(pyuv.UV_WRITABLE, on_write)
loop.run_once()
poll1.close()  # -> crash
poll2.close()