Handle revisions without text

sift/sift.py

@@ -20,12 +20,9 @@ def process_page(page):
         info["redirect"] = page.redirect
     else:
         [revision] = list(page)  # Every page has exactly one revision
+        if revision.text is not None:
+            info["length"] = len(revision.text)
 
-        length = len(revision.text)
-        info["length"] = length
-
-        # Parsing may fail for articles with length 0
-        if length > 0:
             links = []
             for link in wtp.parse(revision.text).wikilinks:
                 start, end = link.span