diff --git a/scripts/bump-version.py b/scripts/bump-version.py
index 8402c36dc..b61c6a060 100644
--- a/scripts/bump-version.py
+++ b/scripts/bump-version.py
@@ -30,6 +30,8 @@
 def replace_in_file(path, pattern, replacement):
     source = path.read_text(**ENC)
     replaced = re.sub(pattern, replacement, source)
+    if replaced == source:
+        raise ValueError('pattern not found')
     path.write_text(replaced, **ENC)