--- a/mercurial/util.py	Thu Apr 05 11:33:36 2018 -0700
+++ b/mercurial/util.py	Thu Apr 05 10:13:01 2018 -0400
@@ -1544,6 +1544,7 @@
 
 # a whilelist of known filesystems where hardlink works reliably
 _hardlinkfswhitelist = {
+    'apfs',
     'btrfs',
     'ext2',
     'ext3',