1 files changed, 5 insertions, 1 deletions
diff --git a/coverage/misc.py b/coverage/misc.py
index 98a5d139..e3c67bc6 100644
--- a/coverage/misc.py
+++ b/coverage/misc.py
@@ -182,7 +182,11 @@ def bool_or_none(b):
 
 def join_regex(regexes):
     """Combine a series of regexes into one that matches any of them."""
-    return "|".join(f"(?:{r})" for r in regexes)
+    regexes = list(regexes)
+    if len(regexes) == 1:
+        return regexes[0]
+    else:
+        return "|".join(f"(?:{r})" for r in regexes)
 
 
 def file_be_gone(path):