Handle foreign exported links in the case of foreign diff specs.

bikeshed/refs/ReferenceManager.py

@@ -400,6 +400,11 @@ def getRef(self, linkType, text, spec=None, status=None, statusHint=None, linkFo
                 return
             # Otherwise
 
+        # Check lower level publications, in case later ones are diff specs
+        # TODO: get metadata on whether a level is a diff spec instead of making this assumption
+        if failure:
+            refs, failure = self.foreignRefs.queryRefs(text=text, linkType=linkType, spec=spec, status=status, statusHint=statusHint, linkFor=linkFor, linkForHint=linkForHint, explicitFor=explicitFor, export=export, ignoreObsoletes=True, latestOnly=False)
+
         if failure == "text" or failure == "type":
             if linkType in ("property", "propdesc", "descriptor") and text.startswith("--"):
                 # Custom properties/descriptors aren't ever defined anywhere