#438 The source info of topic node is not filled when topic directive only contains a bullet list

[Takeshi KOMIYA]

It seems docutils does not fill the topic node with the source info when the topic directive has a bullet list.

from docutils.core import publish_doctree


# topic directive with a paragraph
s = """
.. topic:: 5. Topic Title

   Paragraph
"""

(topic,) = publish_doctree(s)
print(topic.source, topic.line)


# topic directive with a bullet list
s = """
.. topic:: 5. Topic Title

   - Bullet List Item
"""

(topic,) = publish_doctree(s)
print(topic.source, topic.line)

$ python test.py
<string> None
None None

[Günter Milde]

This is one more instance of feature request [#41].
Is there a use case for the internal source and line attributes for topic nodes?

The interesting point is that in some cases there is a "source" attribute (but no "line" attribute) for the "topic" node. (Tested with rst2pseudoxml --expose-internal-attributes=source:line.)