From 6466a3440e4e84d82417021b68f846e9b061cb7f Mon Sep 17 00:00:00 2001
From: Khaled Hosny <khaled@aliftype.com>
Date: Wed, 4 Sep 2024 19:01:20 +0300
Subject: [PATCH] markFeatureWriter: Fix test failures

Check `key` is not empty before accessing first character.
---
 Lib/ufo2ft/featureWriters/markFeatureWriter.py | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/Lib/ufo2ft/featureWriters/markFeatureWriter.py b/Lib/ufo2ft/featureWriters/markFeatureWriter.py
index da1211e2..8d694f82 100644
--- a/Lib/ufo2ft/featureWriters/markFeatureWriter.py
+++ b/Lib/ufo2ft/featureWriters/markFeatureWriter.py
@@ -162,7 +162,7 @@ def parseAnchorName(
     else:
         isMark = False
 
-    isIgnorable = not key[0].isalpha()
+    isIgnorable = key and not key[0].isalpha()
 
     return isMark, key, number, isContextual, isIgnorable