_pip install_ broken beyond normal repair by Jupyter Notebook Extensions (AttributeError: _DistInfoDistribution__dep_map)

[mirekphd]

Installing Jupyter Extensions / Configurator with conda in the versions specified below broke pip 18.0 installer in Python 3.6.5 under Ubuntu 16.04 beyond normal repair, as described in great detail in this fully reproducible bug report submitted to PyPa Github Issues (see #5839)

# Jupyter notebook extensions                                                                                                                     # # caution: Jupyter notebook has to be pinned, because Jupyter notebook extensions not always work with latest versions of notebook
# pin Jupyter Notebook
ARG NB_VER=5.6.0                    
# pin Jupyter notebook extensions
ARG NB_EXT_VER=0.5.0
# pin Jupyter notebook extensions configurator
ARG NB_EXT_CFG_VER=0.4.0

# caution: jupyter notebook extensions do not work unless installed with conda (pip does not suffice)
RUN conda install -c conda-forge notebook=${NB_VER} jupyter_contrib_nbextensions=${NB_EXT_VER} jupyter_nbextensions_configurator=${NB_EXT_CFG_VER}

Note that it is necessary to use conda to cause the reported breakage in pip install. The same extensions builds are harmless when installed with pip, but they are not working either (i.e. they are not available in Notebook unless installed with conda).