Document potentially confusing split_metadata_from_text behavior

Kwpolska · Kwpolska · commit 67b20ee839fc · 2017-07-08T13:06:03.000+02:00
Signed-off-by: Chris Warrick &lt;kwpolska@gmail.com&gt;
diff --git a/nikola/plugin_categories.py b/nikola/plugin_categories.py
@@ -404,7 +404,11 @@ def _extract_metadata_from_text(self, source_text: str) -> dict:
         raise NotImplementedError()
 
     def split_metadata_from_text(self, source_text: str) -> (str, str):
-        """Split text into metadata and content (both strings)."""
+        """Split text into metadata and content (both strings).
+
+        If splitting fails (there is no match), return source_text as both metadata and content.
+        (This behavior is required for 2-file posts.)
+        """
         if self.split_metadata_re is None:
             return source_text, source_text
         else:
