tornado 6.0 breaks notebook

[haokanga]

tornado 6.0 is released at 10AM ET, March 1, 2019, which breaks Jupyter Notebook.
https://pypi.org/project/tornado/6.0/#history

Error message

TypeError: 'type' object is not subscriptable

How to reproduce & Error trace

$ python3 -m venv /home/clouduser/virtualenv 
$ source /home/clouduser/virtualenv/bin/activate
$ pip install pandas jupyter jupyterlab protobuf mysqlclient
$ jupyter notebook --no-browser
Traceback (most recent call last):
  File "/home/clouduser/virtualenv/bin/jupyter-notebook", line 7, in <module>
    from notebook.notebookapp import main
  File "/home/clouduser/virtualenv/lib/python3.5/site-packages/notebook/notebookapp.py", line 47, in <module>
    from zmq.eventloop import ioloop
  File "/home/clouduser/virtualenv/lib/python3.5/site-packages/zmq/eventloop/__init__.py", line 3, in <module>
    from zmq.eventloop.ioloop import IOLoop
  File "/home/clouduser/virtualenv/lib/python3.5/site-packages/zmq/eventloop/ioloop.py", line 21, in <module>
    from tornado import ioloop
  File "/home/clouduser/virtualenv/lib/python3.5/site-packages/tornado/ioloop.py", line 45, in <module>
    from tornado.concurrent import (
  File "/home/clouduser/virtualenv/lib/python3.5/site-packages/tornado/concurrent.py", line 175, in <module>
    future: Union["futures.Future[_T]", "Future[_T]"], value: _T
  File "/usr/lib/python3.5/typing.py", line 552, in __getitem__
    dict(self.__dict__), parameters, _root=True)
  File "/usr/lib/python3.5/typing.py", line 512, in __new__
    for t2 in all_params - {t1} if not isinstance(t2, TypeVar)):
  File "/usr/lib/python3.5/typing.py", line 512, in <genexpr>
    for t2 in all_params - {t1} if not isinstance(t2, TypeVar)):
  File "/usr/lib/python3.5/typing.py", line 190, in __subclasscheck__
    self._eval_type(globalns, localns)
  File "/usr/lib/python3.5/typing.py", line 177, in _eval_type
    eval(self.__forward_code__, globalns, localns),
  File "<string>", line 1, in <module>
TypeError: 'type' object is not subscriptable

Environments

$ cat /etc/os-release
NAME="Ubuntu"
VERSION="16.04.5 LTS (Xenial Xerus)"
ID=ubuntu
ID_LIKE=debian
PRETTY_NAME="Ubuntu 16.04.5 LTS"
VERSION_ID="16.04"
HOME_URL="http://www.ubuntu.com/"
SUPPORT_URL="http://help.ubuntu.com/"
BUG_REPORT_URL="http://bugs.launchpad.net/ubuntu/"
VERSION_CODENAME=xenial
UBUNTU_CODENAME=xenial


$python --version
Python 3.5.2

$ pip freeze
attrs==18.2.0
backcall==0.1.0
bleach==3.1.0
decorator==4.3.2
defusedxml==0.5.0
entrypoints==0.3
ipykernel==5.1.0
ipython==7.3.0
ipython-genutils==0.2.0
ipywidgets==7.4.2
jedi==0.13.3
Jinja2==2.10
jsonschema==3.0.1
jupyter==1.0.0
jupyter-client==5.2.4
jupyter-console==6.0.0
jupyter-core==4.4.0
jupyterlab==0.35.4
jupyterlab-server==0.2.0
MarkupSafe==1.1.1
mistune==0.8.4
mysqlclient==1.4.2.post1
nbconvert==5.4.1
nbformat==4.4.0
notebook==5.7.4
numpy==1.16.2
pandas==0.24.1
pandocfilters==1.4.2
parso==0.3.4
pexpect==4.6.0
pickleshare==0.7.5
pkg-resources==0.0.0
prometheus-client==0.6.0
prompt-toolkit==2.0.9
protobuf==3.7.0
ptyprocess==0.6.0
Pygments==2.3.1
pyrsistent==0.14.11
python-dateutil==2.8.0
pytz==2018.9
pyzmq==18.0.0
qtconsole==4.4.3
Send2Trash==1.5.0
six==1.12.0
terminado==0.8.1
testpath==0.4.2
tornado==6.0
traitlets==4.3.2
wcwidth==0.1.7
webencodings==0.5.1
widgetsnbextension==3.4.2

On our side, we have to downgrade tornado to 5.1.1 to address the issue.

pip install tornado==5.1.1

[mpacer]

This issue also breaks on current notebook even with the latest python and tornado 6.0:

#4399

Does your typing issue persist even with a more recent python version?

[mpacer]

Btw, this is a break that is specific it seems to your use of python 3.5.2

it should be fixed once tornado releases their first patch (probably 6.0.1) which should include tornadoweb/tornado@61e1dbf

That commit has the additional message:

The "provisional" typing module in 3.5.2 is kind of broken/incomplete
so we need to use more forward references to avoid confusing it. The
significance of this version in particular is that it was the one
included in ubuntu 16.04.

But don't worry your title still holds… for the way it is handling zmq, tornado 6.0 still breaks notebook.

[ccordoba12]

Pinging @jjhelmus and @mingwandroid about this problem. Please don't update Tornado in Anaconda until this is solved (it seems Spyder is unaffected by this, but still).

[jjhelmus]

Thanks for the heads up @ccordoba12. We will hold back on the tornado release until this is resolved. Additionally, we make look into adding a upper bound on the tornado version to existing notebook conda packages to prevent users from in inadvertently installing an incompatible version.

[btel]

notebook is still broken with tornado 6.0.1. Although the notebook server runs, it fails to connect to the kernel:

[I 12:43:43.849 NotebookApp] The Jupyter Notebook is running at:
[I 12:43:43.849 NotebookApp] http://localhost:8889/?token=e10b38153224b668f74f3839a2fb60db2e7af66d9d3bb96c
[I 12:43:43.849 NotebookApp] Use Control-C to stop this server and shut down all kernels (twice to skip confirmation).
[C 12:43:43.907 NotebookApp] 
    
    To access the notebook, open this file in a browser:
        file:///run/user/1000/jupyter/nbserver-4991-open.html
    Or copy and paste one of these URLs:
        http://localhost:8889/?token=e10b38153224b668f74f3839a2fb60db2e7af66d9d3bb96c
[I 12:43:48.965 NotebookApp] Creating new notebook in 
[I 12:43:49.771 NotebookApp] Kernel started: cd1d1670-dd78-47a1-b642-d8bedbcdfffd
[I 12:43:50.183 NotebookApp] Adapting to protocol v5.1 for kernel cd1d1670-dd78-47a1-b642-d8bedbcdfffd
/home/bartosz/.pyenv/versions/3.7.2/envs/quantstack-ipywidgets/lib/python3.7/site-packages/notebook/base/zmqhandlers.py:284: RuntimeWarning: coroutine 'WebSocketHandler.get' was never awaited
  super(AuthenticatedZMQStreamHandler, self).get(*args, **kwargs)
RuntimeWarning: Enable tracemalloc to get the object allocation traceback
[W 12:43:51.208 NotebookApp] Replacing stale connection: cd1d1670-dd78-47a1-b642-d8bedbcdfffd:95982ebe348b4ccc99acbd090554aeb9
[W 12:44:13.262 NotebookApp] Replacing stale connection: cd1d1670-dd78-47a1-b642-d8bedbcdfffd:95982ebe348b4ccc99acbd090554aeb9
[W 12:44:37.266 NotebookApp] Replacing stale connection: cd1d1670-dd78-47a1-b642-d8bedbcdfffd:95982ebe348b4ccc99acbd090554aeb9
[W 12:45:05.303 NotebookApp] Replacing stale connection: cd1d1670-dd78-47a1-b642-d8bedbcdfffd:95982ebe348b4ccc99acbd090554aeb9

Downgrading to tornado 5.1.1 solved the issue.

Update: I installed jupyter through pip on Python 3.7.2

[ccordoba12]

Additionally, we make look into adding a upper bound on the tornado version to existing notebook conda packages to prevent users from in inadvertently installing an incompatible version.

Wise decision!! 👍 Could you add it to ipykernel too? That way Tornado updates wouldn't affect Spyder either.

[rohkamat123]

@bdarnell I think this would be helpful for you to know.

[btel]

Please note that this issue breaks the installation via pip.