Running notebooks with Python 3.8.3 causes Assertion errors

Führen Sie das verknüpfte circuits_advanced/1_advanced_circuits.ipynb in einem frischen Kernel unter Python 3.8.3 erneut aus und untersuchen Sie anschließend die Stellen des Tracebacks in ipykernel/kernelbase.py und tornado/ioloop.py. Vergleichen Sie dies mit Python 3.8.2 oder 3.7.x, unter denen das Notebook funktioniert; abgeschlossen ist die Aufgabe, wenn die Kompatibilitätsursache identifiziert und der daraus resultierende Fix oder die Änderung der Abhängigkeit verifiziert wurde.

Since upgrading to the latest python release 3.8.3 on my system I have had issues running a notebook, specifically: https://github.com/Qiskit/qiskit-tutorials/blob/master/tutorials/circuits_advanced/1_advanced_circuits.ipynb Running that notebook when you run it from scratch on a fresh kernel it hangs on cell 8 and the jupyter notebook output logs multiple assertion errors:

[I 07:27:26.810 NotebookApp] Replaying 3 buffered messages
[IPKernelApp] ERROR | Exception in message handler:
Traceback (most recent call last):
  File "/tmp/test-tutorials/lib/python3.8/site-packages/ipykernel/kernelbase.py", line 268, in dispatch_shell
    yield gen.maybe_future(handler(stream, idents, msg))
  File "/tmp/test-tutorials/lib/python3.8/site-packages/tornado/gen.py", line 735, in run
    value = future.result()
  File "/tmp/test-tutorials/lib/python3.8/site-packages/tornado/gen.py", line 209, in wrapper
    yielded = next(result)
  File "/tmp/test-tutorials/lib/python3.8/site-packages/ipykernel/kernelbase.py", line 543, in execute_request
    self.do_execute(
  File "/tmp/test-tutorials/lib/python3.8/site-packages/tornado/gen.py", line 225, in wrapper
    runner = Runner(result, future, yielded)
  File "/tmp/test-tutorials/lib/python3.8/site-packages/tornado/gen.py", line 712, in __init__
    if self.handle_yield(first_yielded):
  File "/tmp/test-tutorials/lib/python3.8/site-packages/tornado/gen.py", line 789, in handle_yield
    self.io_loop.add_future(self.future, inner)
  File "/tmp/test-tutorials/lib/python3.8/site-packages/tornado/ioloop.py", line 693, in add_future
    assert is_future(future)
AssertionError
[IPKernelApp] ERROR | Exception in message handler:
Traceback (most recent call last):
  File "/tmp/test-tutorials/lib/python3.8/site-packages/ipykernel/kernelbase.py", line 268, in dispatch_shell
    yield gen.maybe_future(handler(stream, idents, msg))
  File "/tmp/test-tutorials/lib/python3.8/site-packages/tornado/gen.py", line 735, in run
    value = future.result()
  File "/tmp/test-tutorials/lib/python3.8/site-packages/tornado/gen.py", line 209, in wrapper
    yielded = next(result)
  File "/tmp/test-tutorials/lib/python3.8/site-packages/ipykernel/kernelbase.py", line 543, in execute_request
    self.do_execute(
  File "/tmp/test-tutorials/lib/python3.8/site-packages/tornado/gen.py", line 225, in wrapper
    runner = Runner(result, future, yielded)
  File "/tmp/test-tutorials/lib/python3.8/site-packages/tornado/gen.py", line 712, in __init__
    if self.handle_yield(first_yielded):
  File "/tmp/test-tutorials/lib/python3.8/site-packages/tornado/gen.py", line 789, in handle_yield
    self.io_loop.add_future(self.future, inner)
  File "/tmp/test-tutorials/lib/python3.8/site-packages/tornado/ioloop.py", line 693, in add_future
    assert is_future(future)
AssertionError
[IPKernelApp] ERROR | Exception in message handler:
Traceback (most recent call last):
  File "/tmp/test-tutorials/lib/python3.8/site-packages/ipykernel/kernelbase.py", line 268, in dispatch_shell
    yield gen.maybe_future(handler(stream, idents, msg))
  File "/tmp/test-tutorials/lib/python3.8/site-packages/tornado/gen.py", line 735, in run
    value = future.result()
  File "/tmp/test-tutorials/lib/python3.8/site-packages/tornado/gen.py", line 209, in wrapper
    yielded = next(result)
  File "/tmp/test-tutorials/lib/python3.8/site-packages/ipykernel/kernelbase.py", line 543, in execute_request
    self.do_execute(
  File "/tmp/test-tutorials/lib/python3.8/site-packages/tornado/gen.py", line 225, in wrapper
    runner = Runner(result, future, yielded)
  File "/tmp/test-tutorials/lib/python3.8/site-packages/tornado/gen.py", line 712, in __init__
    if self.handle_yield(first_yielded):
  File "/tmp/test-tutorials/lib/python3.8/site-packages/tornado/gen.py", line 789, in handle_yield
    self.io_loop.add_future(self.future, inner)
  File "/tmp/test-tutorials/lib/python3.8/site-packages/tornado/ioloop.py", line 693, in add_future
    assert is_future(future)
AssertionError
[IPKernelApp] ERROR | Exception in message handler:
Traceback (most recent call last):
  File "/tmp/test-tutorials/lib/python3.8/site-packages/ipykernel/kernelbase.py", line 268, in dispatch_shell
    yield gen.maybe_future(handler(stream, idents, msg))
  File "/tmp/test-tutorials/lib/python3.8/site-packages/tornado/gen.py", line 735, in run
    value = future.result()
  File "/tmp/test-tutorials/lib/python3.8/site-packages/tornado/gen.py", line 209, in wrapper
    yielded = next(result)
  File "/tmp/test-tutorials/lib/python3.8/site-packages/ipykernel/kernelbase.py", line 543, in execute_request
    self.do_execute(
  File "/tmp/test-tutorials/lib/python3.8/site-packages/tornado/gen.py", line 225, in wrapper
    runner = Runner(result, future, yielded)
  File "/tmp/test-tutorials/lib/python3.8/site-packages/tornado/gen.py", line 712, in __init__
    if self.handle_yield(first_yielded):
  File "/tmp/test-tutorials/lib/python3.8/site-packages/tornado/gen.py", line 789, in handle_yield
    self.io_loop.add_future(self.future, inner)
  File "/tmp/test-tutorials/lib/python3.8/site-packages/tornado/ioloop.py", line 693, in add_future
    assert is_future(future)
AssertionError

Downgrading python to 3.8.2 (or 3.7.x) fixes this. I've also confirmed it on other platforms (I run on linux, but mac users running 3.8.3 have had the same issue). I assume this is probably a bug in python or tornado, but I lack the domain expertise on the stack to be sure.