Fix 'make gettext' fails when the '.. todolist::' directive is present. Closes #1364

Nodes that are replicated like todo don't have a uid, however i18n also unnecessary.
If extensions need to choose i18n for the extended nodes or not, we need another approach.

CHANGES

@@ -20,6 +20,7 @@ Bugs fixed
 * #1386: Fix bug preventing more than one theme being added by the entry point
   mechanism.
 * #1370: Ignore "toctree" nodes in text writer, instead of raising.
+* #1364: Fix 'make gettext' fails when the '.. todolist::' directive is present.
 
 Documentation
 -------------

sphinx/builders/gettext.py

@@ -55,6 +55,9 @@ class Catalog(object):
         self.metadata = {}  # msgid -> file, line, uid
 
     def add(self, msg, origin):
+        if not hasattr(origin, 'uid'):
+            # Nodes that are replicated like todo don't have a uid, however i18n is also unnecessary.
+            return
         if msg not in self.metadata:  # faster lookup in hash
             self.messages.append(msg)
             self.metadata[msg] = []