mercurial/obsutil.py

--- a/mercurial/obsutil.py	Mon Jul 03 15:33:27 2017 +0200
+++ b/mercurial/obsutil.py	Mon Jul 03 15:34:00 2017 +0200
@@ -601,3 +601,11 @@
     else:
         verb = 'split'
     return verb
+
+def markersusers(markers):
+    """ Returns a sorted list of markers users without duplicates
+    """
+    markersmeta = [dict(m[3]) for m in markers]
+    users = set(meta.get('user') for meta in markersmeta if meta.get('user'))
+
+    return sorted(users)