Handle link://category with an error

Roberto Alsina · Roberto Alsina · commit 741fb2e69ee2 · 2017-04-19T10:37:33.000-03:00
diff --git a/nikola/plugins/task/categories.py b/nikola/plugins/task/categories.py
@@ -116,6 +116,9 @@ def slugify_tag_name(self, name, lang):
 
     def slugify_category_name(self, path, lang):
         """Slugify a category name."""
+        if not path:  # Probably used link://category
+            utils.LOGGER.error('Invalid link to a category without passing a category name. Probably meant to use category_index?')
+            raise ValueError()
         if lang is None:  # TODO: remove in v8
             utils.LOGGER.warn("ClassifyCategories.slugify_category_name() called without language!")
             lang = ''
