+Add symbol hiding so that we don't risk leaking any private symbols
+into the shared-library interface.
+
+Audit all libnotmuch entry points to ensure that all Xapian calls are
+wrapped in a try/catch block.
+
+Fix the "count" functionality to be exact as Olly explained in IRC:
+
+ ojwb> cworth: if you set the check_at_least parameter to the
+ database size, get_matches_estimated() will be exact
+
+Fix the threading of a message that has a References: header but no
+In-Reply-To: header (see id:"87lixxnxpb.fsf@yoom.home.cworth.org").
+
+Search syntax
+-------------
+Implement support for "tag:*" to expand to all tags.
+
+Fix "notmuch search to:" to be less confusing. Many users expect this
+to search for all messages with a To: header, but it instead searches
+for all messages with the word "to". If we don't provide the first
+behavior, perhaps we should exit on an error when a configured prefix
+is provided with no value?
+
+Support "*" in all cases and not just as a special case. That is, "* "
+should also work, as well as "* and tag:inbox".
+
+Implement a syntax for requesting set-theoertic operations on results
+of multiple searches. For example, I would like to do:
+
+ "tag:inbox" SET-SUBTRACT "tag:muted"
+
+ as well as:
+
+ "tag:notmuch and <date-range>" SET-INTERSECT
+ "tag:notmuch and not (tag:merged or tag:postponed)"
+
+ See id:3wdpr282yz2.fsf@testarossa.amd.com for more details on the
+ use cases of the above.
+
+Database changes
+----------------
+Store a reference term for every message-id that appears in
+References. We just started doing this for newly-added documents, but
+at the next convenient database-schema upgrade, we should go back and
+fix old messages to be consistent.
+
+Start indexing the List-Id header, (and re-index this header for
+existing messages at the next database upgrade).
+
+Add support for the user to specify custom headers to be indexed (and
+re-index these for existing messages at the next database upgrade).
+
+Save filenames for files detected as "not an email file" in the
+database. This would allow for two things: 1. Optimizing "notmuch new"
+to not have to look at these files again (since they are potentially
+large so the detection could be potentially slow). 2. A "notmuch
+search" syntax could be added to allow the user to find these files,
+(and perhaps delete them or move them away as appropriate).
+
+Fix filesystem/notmuch-new race condition by not updating database
+mtime for a directory if it is the same as the current mtime.
+
+Test suite
+----------
+Achieve 100% test coverage with the test suite.
+