Robert Lupton No, I don't think we will have any failures as the doc is cast to a str before prepending the true comment style (# as 1st character in line). I think the only other place this was causing a problem was introduced as a check for triple quotes in the doc string (as the presence of them within the docstring itself would have resulted in a delimiter collision with the use of the ''' as delimiting the multiline string). The fix in HSC-1072 was just to add an if doc: prior to the test. Since we are now using the true comment style, there is no such restriction for the docstring itself, so the check is never made.
I have tested this by adding a doc=None test config parameter in the tests/config.py unittest in pex_config and it passed through just fine. Note that this test did not end up getting added to master given the discussions suggesting that doc=None should NOT be allowed/accommodated, and hence the creation of this ticket!
Do let me know if I am mistaken and there is another mode where this could fail.