Pickling Error with 1.8

[blink1073]

Subject: Sphinx 1.8 introduced a build error for JupyterLab

Problem

• It appears that in 1.8 the url_resolver config is trying to get pickled. We had a lambda function, but that broke with (cf https://travis-ci.org/jupyterlab/jupyterlab/jobs/427847089#L672):

AttributeError: Can't pickle local object 'setup.<locals>.<lambda>'

Changing it to a separate function yields (cf https://travis-ci.org/jupyterlab/jupyterlab/jobs/428072324#L763 and https://github.com/jupyterlab/jupyterlab/pull/5308/files):

_pickle.PicklingError: Can't pickle <function url_resolver at 0x2b0913492e18>: attribute lookup url_resolver on __main__ failed

Procedure to reproduce the problem

git clone https://github.com/jupyterlab/jupyterlab
cd jupyterlab/docs
pip install sphinx=1.8 sphinx_rtd_theme recommonmark
make html

Environment info

• OS: MacOS 10.13.6
• Python version: 3.6.3
• Sphinx version: 1.8.0

[tk0miya]

It seems the error comes from the default setting for recommonmark.AutoStructify.
I'll take a look this later.

Note: I confirmed this with following dockerfile:

FROM tk0miya/sphinx-html

RUN git clone https://github.com/jupyterlab/jupyterlab
WORKDIR /docs/jupyterlab/docs
RUN pip3 install sphinx==1.8 sphinx_rtd_theme recommonmark
RUN make html SPHINXBUILD='python3 -msphinx'

[blink1073]

Cheers!

[tk0miya]

Fixed by #5429 .
Thank you for reporting.

[blink1073]

🎉