modules-4.4.0: doc build fails due to incorrect markup

[xdelaruelle]

Ticket received by email from @balducci

Hello,

During modules-4.4.0 build I get:

----8<----
make -C doc man txt
make[2]: Entering directory '/home/login/tmp/install-us-d/modules-4.3.1.d/modules-4.4.0/doc'
sed -e 's|@prefix@|/opt/stow.d/versions/modules-4.4.0/usr|g' -e 's|@libexecdir@|/opt/stow.d/versions/modules-4.4.0/usr/libexec|g' -e 's|@etcdir@|/opt/stow.d/versions/modules-4.4.0/etc/modules/configfiles|g' -e 's|@initdir@|/opt/stow.d/versions/modules-4.4.0/etc/modules/init|g' -e 's|@modulefilesdir@|/etc/modules/modulefiles|g' -e 's|@MODULES_RELEASE@|4.4.0|g' -e 's|@MODULES_BUILD@||g' -e 's|@MODULES_BUILD_DATE@|2019-11-17|g' source/version.py.in > source/version.py
/usr/bin/sphinx-build -q -t pathsubs -b man "source" "build"

Exception occurred:
  File "/usr/python3/site_python3/lib64/Sphinx.egg/sphinx/util/nodes.py", line 151, in apply_source_workaround
    for classifier in reversed(node.parent.traverse(nodes.classifier)):
TypeError: '_traversal_list' object is not reversible
The full traceback has been saved in /tmp/sphinx-err-_dciwbdh.log, if you want to report the issue to the developers.
Please also report this if it was a user error, so that a better error message can be provided next time.
A bug report can be filed in the tracker at <https://github.com/sphinx-doc/sphinx/issues>. Thanks!
make[2]: *** [Makefile:75: build/module.1.in] Error 2
make[2]: Leaving directory '/home/login/tmp/install-us-d/modules-4.3.1.d/modules-4.4.0/doc'
---->8----

Turns out that the reason is (apparently) broken markup in the .rst files in source/design, where a blank line before the first item of bullet lists is missing. Actually, adding those blank lines where needed fixes the build for me.

thanks a lot for your valuable work

ciao
-gabriele

PS: if that matters, the docs are being built with docutils (master) and Sphinx-2.2.2

[xdelaruelle]

Relates to sphinx-doc/sphinx#6887.