[Pkg-emacsen-addons] Bug#929232: flycheck: FTBFS (ValueError: Invalid placeholder in string)

[Santiago Vila]

Package: src:flycheck
Version: 31-2
Severity: serious
Tags: ftbfs

Dear maintainer:

I tried to build this package in buster but it failed:

--------------------------------------------------------------------------------
[...]
 debian/rules build-indep
dh build-indep --with elpa,sphinxdoc
   dh_update_autotools_config -i
   dh_autoreconf -i
   dh_auto_configure -i
   debian/rules override_dh_auto_build
make[1]: Entering directory '/<<PKGBUILDDIR>>'
( cd doc && make OFFLINE=yes html )
make[2]: Entering directory '/<<PKGBUILDDIR>>/doc'
sphinx-build -b html -d _build/doctrees -j4 . -Dflycheck_offline_html=1 _build/html
Running Sphinx v1.8.4
making output directory...
loading intersphinx inventory from https://docs.python.org/3.5/objects.inv...
fetching Texinfo htmlxref database from http://ftpmirror.gnu.org/texinfo/htmlxref.cnf... 
/<<PKGBUILDDIR>>/doc/info.py:135: RemovedInSphinx20Warning: app.info() is now deprecated. Use sphinx.util.logging instead.
  HTMLXRefDB.XREF_URL))

Exception occurred:
  File "/usr/lib/python3.7/string.py", line 105, in _invalid
    (lineno, colno))
ValueError: Invalid placeholder in string: line 1, col 1
The full traceback has been saved in /tmp/sphinx-err-7maxd4u7.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:90: html] Error 2
make[2]: Leaving directory '/<<PKGBUILDDIR>>/doc'
make[1]: *** [debian/rules:11: override_dh_auto_build] Error 2
make[1]: Leaving directory '/<<PKGBUILDDIR>>'
make: *** [debian/rules:4: build-indep] Error 2
dpkg-buildpackage: error: debian/rules build-indep subprocess returned exit status 2
--------------------------------------------------------------------------------

(The build was made with "dpkg-buildpackage -A" but I don't think it's relevant here)

The following lines are very suspicious:

 loading intersphinx inventory from https://docs.python.org/3.5/objects.inv...
 fetching Texinfo htmlxref database from http://ftpmirror.gnu.org/texinfo/htmlxref.cnf...

Packages must not use the network for building.

If this is really a bug in one of the build-depends, please use reassign and affects,
so that this is still visible in the BTS web page for this package.

Thanks.