--- a/hgext3rd/evolve/compat.py	Thu Aug 02 16:54:40 2018 +0300
+++ b/hgext3rd/evolve/compat.py	Fri Aug 03 00:52:10 2018 +0200
@@ -11,6 +11,7 @@
 from mercurial import (
     context,
     copies,
+    encoding,
     mdiff,
     obsolete,
     obsutil,
@@ -701,5 +702,85 @@
 if util.safehasattr(copies, '_fullcopytracing'):
     copies._fullcopytracing = fixedcopytracing
 elif util.safehasattr(copies, 'mergecopies'):
-    # comapt fix for hg <= 4.3
+    # compat fix for hg <= 4.3
     copies.mergecopies = fixoldmergecopies
+
+if not util.safehasattr(obsutil, "_succs"):
+    class _succs(list):
+        """small class to represent a successors with some metadata about it"""
+
+        def __init__(self, *args, **kwargs):
+            super(_succs, self).__init__(*args, **kwargs)
+            self.markers = set()
+
+        def copy(self):
+            new = _succs(self)
+            new.markers = self.markers.copy()
+            return new
+
+        @util.propertycache
+        def _set(self):
+            # immutable
+            return set(self)
+
+        def canmerge(self, other):
+            return self._set.issubset(other._set)
+else:
+    from mercurial.obsutil import _succs
+
+def wrap_succs(succs):
+    """ Wrap old data format of successorsets (tuple) only if if's not yet a
+    _succs instance
+    """
+
+    if not util.safehasattr(succs, "markers"):
+        return _succs(succs)
+    else:
+        return succs
+
+if not util.safehasattr(obsutil, "markersdates"):
+    MARKERS_DATE_COMPAT = True
+else:
+    MARKERS_DATE_COMPAT = False
+
+def markersdates(markers):
+    """returns the list of dates for a list of markers
+    """
+    if MARKERS_DATE_COMPAT is False:
+        return obsutil.markersdates(markers)
+
+    return [m[4] for m in markers]
+
+if not util.safehasattr(obsutil, "markersusers"):
+    MARKERS_USERS_COMPAT = True
+else:
+    MARKERS_USERS_COMPAT = False
+
+def markersusers(markers):
+    """ Returns a sorted list of markers users without duplicates
+    """
+    if MARKERS_USERS_COMPAT is False:
+        return obsutil.markersusers(markers)
+
+    markersmeta = [dict(m[3]) for m in markers]
+    users = set(encoding.tolocal(meta['user']) for meta in markersmeta
+                if meta.get('user'))
+
+    return sorted(users)
+
+if not util.safehasattr(obsutil, "markersoperations"):
+    MARKERS_OPERATIONS_COMPAT = True
+else:
+    MARKERS_OPERATIONS_COMPAT = False
+
+def markersoperations(markers):
+    """ Returns a sorted list of markers operations without duplicates
+    """
+    if MARKERS_OPERATIONS_COMPAT is False:
+        return obsutil.markersoperations(markers)
+
+    markersmeta = [dict(m[3]) for m in markers]
+    operations = set(meta.get('operation') for meta in markersmeta
+                     if meta.get('operation'))
+
+    return sorted(operations)

--- a/hgext3rd/evolve/obshistory.py	Thu Aug 02 16:54:40 2018 +0300
+++ b/hgext3rd/evolve/obshistory.py	Fri Aug 03 00:52:10 2018 +0200
@@ -107,7 +107,7 @@
     fullsuccessorsets = [] # successor set + markers
     for sset in ssets:
         if sset:
-            fullsuccessorsets.append(sset)
+            fullsuccessorsets.append(compat.wrap_succs(sset))
         else:
             # successorsset return an empty set() when ctx or one of its
             # successors is pruned.
@@ -123,11 +123,11 @@
             for mark in succsmap.get(ctx.node(), ()):
                 if not mark[1]:
                     foundany = True
-                    sset = obsutil._succs()
+                    sset = compat._succs()
                     sset.markers.add(mark)
                     fullsuccessorsets.append(sset)
             if not foundany:
-                fullsuccessorsets.append(obsutil._succs())
+                fullsuccessorsets.append(compat._succs())
 
     values = []
     for sset in fullsuccessorsets:
@@ -673,7 +673,7 @@
                  label="evolve.node")
 
     # Operations
-    operations = obsutil.markersoperations(markers)
+    operations = compat.markersoperations(markers)
     if operations:
         fm.plain(' using ')
         fm.write('operation', '%s', ", ".join(operations), label="evolve.operation")
@@ -681,13 +681,13 @@
     fm.plain(' by ')
 
     # Users
-    users = obsutil.markersusers(markers)
+    users = compat.markersusers(markers)
     fm.write('user', '%s', ", ".join(users),
              label="evolve.user")
     fm.plain(' ')
 
     # Dates
-    dates = obsutil.markersdates(markers)
+    dates = compat.markersdates(markers)
     if dates:
         min_date = min(dates)
         max_date = max(dates)