nb_execution_show_tb seems to not do anything

[basnijholt]

Describe the bug

context When I set nb_execution_show_tb = True in my conf.py and my CI build fails, no exceptions are printed.

Possibly relevant packages installed by CI:

jupyter-cache/0.5/jupyter_cache-0.5.0-py3-none-any.whl (34 kB)
jupyter-client/8.1/jupyter_client-8.1.0-py3-none-any.whl (102 kB)
jupyter-core/5.3/jupyter_core-5.3.0-py3-none-any.whl (93 kB)
jupyter-events/0.6.3/jupyter_events-0.6.3-py3-none-any.whl (18 kB)
jupyter-server-terminals/0.4.4/jupyter_server_terminals-0.4.4-py3-none-any.whl (13 kB)
jupyter-server/2.5/jupyter_server-2.5.0-py3-none-any.whl (366 kB)
jupyterlab-pygments/0.2.2/jupyterlab_pygments-0.2.2-py2.py3-none-any.whl (21 kB)
jupyterlab-widgets/3.0.6/jupyterlab_widgets-3.0.6-py3-none-any.whl (198 kB)
jupytext/1.14.5/jupytext-1.14.5-py3-none-any.whl (298 kB)
myst-nb/0.17.1/myst_nb-0.17.1-py3-none-any.whl (78 kB)
myst-parser/0.18.1/myst_parser-0.18.1-py3-none-any.whl (58 kB)
notebook/6.5.2/notebook-6.5.2-py3-none-any.whl (439 kB)
notebook/6.5.3/notebook-6.5.3-py3-none-any.whl (529 kB)
sphinx-basic-ng/1b1/sphinx_basic_ng-1.0.0b1-py3-none-any.whl (22 kB)
sphinx/5.3/sphinx-5.3.0-py3-none-any.whl (3.2 MB)
sphinx/6.1.3/sphinx-6.1.3-py3-none-any.whl (3.0 MB)
sphinxcontrib-apidoc/0.2.1/sphinxcontrib_apidoc-0.2.1-py2.py3-none-any.whl (6.9 kB)
sphinxcontrib-apidoc/0.3/sphinxcontrib_apidoc-0.3.0-py2.py3-none-any.whl (8.5 kB)
sphinxcontrib-applehelp/1.0.4/sphinxcontrib_applehelp-1.0.4-py3-none-any.whl (120 kB)
sphinxcontrib-devhelp/1.0.2/sphinxcontrib_devhelp-1.0.2-py2.py3-none-any.whl (84 kB)
sphinxcontrib-htmlhelp/2.0.1/sphinxcontrib_htmlhelp-2.0.1-py3-none-any.whl (99 kB)
sphinxcontrib-jsmath/1.0.1/sphinxcontrib_jsmath-1.0.1-py2.py3-none-any.whl (5.1 kB)
sphinxcontrib-qthelp/1.0.3/sphinxcontrib_qthelp-1.0.3-py2.py3-none-any.whl (90 kB)
sphinxcontrib-serializinghtml/1.1.5/sphinxcontrib_serializinghtml-1.1.5-py2.py3-none-any.whl (94 kB)

Reproduce the bug

Make a failing .md file and observe the absence of exceptions in the logs.

List your environment

Can't run this in CI.

It is installing latest versions.

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[tillahoffmann]

Is it possible that the traceback is not showing because nb_execution_raise_on_error = True (cf. #531)? A workaround for me has been to leave nb_execution_raise_on_error = False but invoke Sphinx with the -W flag which turns warnings into errors.

[agoose77]

As discussed in https://github.com/executablebooks/MyST-NB/pull/531#issuecomment-1689623625, I think you just need to turn on nb_execution_raise_on_error, and run sphinx-build with -T in order for this to work. The nb_execution_show_tb option seems like a workaround for cases when we don't have access to sphinx-build arguments, in which case https://github.com/executablebooks/MyST-NB/issues/482#issuecomment-1684151372 is the appropriate usage.

However, #531 has merged, so in future nb_execution_raise_on_error should have no effect upon nb_execution_show_tb.