sphinx + breatheでAttributeError: 'NoneType' object has no attribute 'replace'

以下のようなエラーがSphinx + Breatheで出る。

# Sphinx version: 1.6.3
# Python version: 3.6.2rc1 (CPython)
# Docutils version: 0.13.1 release
# Jinja2 version: 2.9.6
# Last messages:
#   building [mo]: targets for 0 po files that are out of date
#
#   building [html]: targets for 1 source files that are out of date
#
#   updating environment:
#
#   1 added, 0 changed, 0 removed
#
#   reading sources... [100%] index
#
# Loaded extensions:
#   alabaster (0.7.10) from /usr/local/lib/python3.6/site-packages/alabaster/__init__.py
#   breathe (4.6.0) from /usr/local/lib/python3.6/site-packages/breathe/__init__.py
#   sphinx.ext.todo (1.6.3) from /usr/local/lib/python3.6/site-packages/sphinx/ext/todo.py
#   sphinx.ext.mathjax (1.6.3) from /usr/local/lib/python3.6/site-packages/sphinx/ext/mathjax.py
Traceback (most recent call last):
  File "/usr/local/lib/python3.6/site-packages/sphinx/cmdline.py", line 306, in main
    app.build(opts.force_all, filenames)
  File "/usr/local/lib/python3.6/site-packages/sphinx/application.py", line 339, in build
    self.builder.build_update()
  File "/usr/local/lib/python3.6/site-packages/sphinx/builders/__init__.py", line 331, in build_update
    'out of date' % len(to_build))
  File "/usr/local/lib/python3.6/site-packages/sphinx/builders/__init__.py", line 344, in build
    updated_docnames = set(self.env.update(self.config, self.srcdir, self.doctreedir))
  File "/usr/local/lib/python3.6/site-packages/sphinx/environment/__init__.py", line 583, in update
    self._read_serial(docnames, self.app)
  File "/usr/local/lib/python3.6/site-packages/sphinx/environment/__init__.py", line 602, in _read_serial
    self.read_doc(docname, app)
  File "/usr/local/lib/python3.6/site-packages/sphinx/environment/__init__.py", line 723, in read_doc
    pub.publish()
  File "/usr/local/lib/python3.6/site-packages/docutils/core.py", line 218, in publish
    self.apply_transforms()
  File "/usr/local/lib/python3.6/site-packages/docutils/core.py", line 199, in apply_transforms
    self.document.transformer.apply_transforms()
  File "/usr/local/lib/python3.6/site-packages/docutils/transforms/__init__.py", line 171, in apply_transforms
    transform.apply(**kwargs)
  File "/usr/local/lib/python3.6/site-packages/docutils/transforms/universal.py", line 294, in apply
    txtnode.parent.replace(txtnode, nodes.Text(newtext))
AttributeError: 'NoneType' object has no attribute 'replace'

breatheのbug

• Smart quotes cause Sphinx to crash inside docutils · Issue #3709 · sphinx-doc/sphinx · GitHub

issueに解決方法が記載してある。 以下の該当行を次のコードで置き換えれば良い。

https://github.com/michaeljones/breathe/blob/d3eae7fac4d2ead062070fd149ec8bf839f74ed5/breathe/renderer/sphinxrenderer.py#L1103

        if nodelist:
            # nodelist[0].children = [term, separator] + nodelist[0].children
            nodelist[0].insert(0, term)
            nodelist[0].insert(1, separator)
        else:
            nodelist = [term]