So I am tracking the same issue seen on Ubuntu 16.10 and I found:
https://github.com/sphinx-doc/sphinx/pull/2396
I tested the following patch to the sourc3, and it does seem to build,
although I'm not sure I fully understand why yet (I'm completely new to
sphinx, just trying to help fix these bugs :) But I think it's because
upstream sphinx has changed an underlying data structure (index)?
-Nish
--- a/doc/build/templates/genindex.mako
+++ b/doc/build/templates/genindex.mako
@@ -21,7 +21,7 @@
numcols = 1
numitems = 0
%>
-% for entryname, (links, subitems) in entries:
+% for entryname, (links, subitems, dummy) in entries:
<dt>
% if links:
--
Nishanth Aravamudan
Ubuntu Server
Canonical Ltd
