mercurial/hg.py

--- a/mercurial/hg.py	Sun Apr 08 08:53:43 2018 -0700
+++ b/mercurial/hg.py	Sun Apr 08 09:30:35 2018 -0700
@@ -66,9 +66,7 @@
     hashbranch, branches = branches
     if not hashbranch and not branches:
         x = revs or None
-        if util.safehasattr(revs, 'first'):
-            y = revs.first()
-        elif revs:
+        if revs:
             y = revs[0]
         else:
             y = None