1 files changed, 3 insertions, 1 deletions
diff --git a/coverage/misc.py b/coverage/misc.py
index ec0d0ff7..fd9be857 100644
--- a/coverage/misc.py
+++ b/coverage/misc.py
@@ -77,8 +77,10 @@ def join_regex(regexes):
     """Combine a list of regexes into one that matches any of them."""
     if len(regexes) > 1:
         return "(" + ")|(".join(regexes) + ")"
-    else:
+    elif regexes:
         return regexes[0]
+    else:
+        return ""
 
 
 class Hasher(object):