Import datashader in Jupter notebook with Python 3.5 kernel hangs cell.

Description

If install a fresh Python 3.5.2 environment with just Jupyter and Datashader (with dependencies), then try and import Datashader in the notebook, the notebook hangs in any cells run after the datashader import.

This does not happen when running from an ipython terminal or if using Python 3.7

How to reproduce

From the CLI: python 3.5 -m venv venv . venv/bin/activate pip install jupyter datashader jupyter notebook

In the notebook: import datashader - Cell 1

print('hello') - Cell 2

The print('hello') command will not complete after Cell 1 has finished running. No warnings are given.

Errors and warnings

Looking at the debug output of the terminal when running the notebook, the pattern of status, execute_input and stream is broken, the execute_inpu part doesn’t run again.

Your environment

Ubuntu 16.04 Python 3.5.2 Firefox 66.0.5

attrs==19.1.0 backcall==0.1.0 bleach==3.1.0 bokeh==1.1.0 certifi==2019.3.9 chardet==3.0.4 Click==7.0 cloudpickle==1.1.1 colorcet==2.0.1 cycler==0.10.0 dask==1.2.2 datashader==0.7.0 datashape==0.5.2 decorator==4.4.0 defusedxml==0.6.0 distributed==1.28.1 entrypoints==0.3 HeapDict==1.0.0 idna==2.8 imageio==2.5.0 ipykernel==5.1.1 ipython==7.5.0 ipython-genutils==0.2.0 ipywidgets==7.4.2 jedi==0.13.3 Jinja2==2.10.1 jsonschema==3.0.1 jupyter==1.0.0 jupyter-client==5.2.4 jupyter-console==6.0.0 jupyter-core==4.4.0 kiwisolver==1.1.0 llvmlite==0.28.0 locket==0.2.0 MarkupSafe==1.1.1 matplotlib==3.0.3 mistune==0.8.4 msgpack==0.6.1 multipledispatch==0.6.0 nbconvert==5.5.0 nbformat==4.4.0 networkx==2.3 notebook==5.7.8 numba==0.43.1 numpy==1.16.3 packaging==19.0 pandas==0.24.2 pandocfilters==1.4.2 param==1.9.0 parso==0.4.0 partd==0.3.10 pexpect==4.7.0 pickleshare==0.7.5 Pillow==6.0.0 pkg-resources==0.0.0 prometheus-client==0.6.0 prompt-toolkit==2.0.9 psutil==5.6.2 ptyprocess==0.6.0 pyct==0.4.6 Pygments==2.4.0 pyparsing==2.4.0 pyrsistent==0.15.2 python-dateutil==2.8.0 pytz==2019.1 PyWavelets==1.0.3 PyYAML==5.1 pyzmq==18.0.1 qtconsole==4.4.4 requests==2.22.0 scikit-image==0.15.0 scipy==1.3.0 Send2Trash==1.5.0 six==1.12.0 sortedcontainers==2.1.0 tblib==1.4.0 terminado==0.8.2 testpath==0.3.1 toolz==0.9.0 tornado==6.0.2 traitlets==4.3.2 urllib3==1.25.2 wcwidth==0.1.7 webencodings==0.5.1 widgetsnbextension==3.4.2 xarray==0.12.1 zict==0.1.4

[akum036]

We use 3.5 as it’s the default in Ubuntu 16.04 LTS.

[jbednar]

Ok, thanks. @jsignell, please remove 3.5 from the PR unless you see a simple way to fix the 3.5 tests.