diff --git a/services/comparison.py b/services/comparison.py
index db1e02229f..9c531fb3a0 100644
--- a/services/comparison.py
+++ b/services/comparison.py
@@ -397,6 +397,8 @@ class Segment:
     @classmethod
     def segments(cls, file_comparison):
         lines = file_comparison.lines
+        if lines is None:
+            return []
 
         # line numbers of interest (i.e. coverage changed or code changed)
         line_numbers = []