--- a/hgext3rd/evolve/evolvecmd.py	Fri Apr 19 10:41:56 2019 -0700
+++ b/hgext3rd/evolve/evolvecmd.py	Fri Apr 19 10:47:12 2019 -0700
@@ -180,7 +180,7 @@
             newid = relocate(repo, orig, target, evolvestate, pctx,
                              keepbranch, 'orphan')
             return (True, newid)
-        except MergeFailure:
+        except error.InterventionRequired:
             ops = {'current': orig.node()}
             evolvestate.addopts(ops)
             evolvestate.save()
@@ -249,7 +249,7 @@
                                        operation='evolve')
                 bumped = new
                 evolvestate['temprevs'].append(newnode)
-        except MergeFailure:
+        except error.InterventionRequired:
             evolvestate['current'] = bumped.hex()
             evolvestate['precursor'] = prec.hex()
             evolvestate.save()
@@ -514,7 +514,7 @@
         try:
             newother = relocate(repo, other, divergent.p1(), evolvestate,
                                 keepbranch=True)
-        except MergeFailure:
+        except error.InterventionRequired:
             evolvestate['current'] = other.node()
             evolvestate.save()
             raise error.InterventionRequired(_("fix conflicts and see `hg help "
@@ -893,9 +893,6 @@
 
     return desc
 
-class MergeFailure(error.Abort):
-    pass
-
 def _orderrevs(repo, revs):
     """Compute an ordering to solve instability for the given revs
 
@@ -991,8 +988,8 @@
                                    orig.p1().rev())
             dirstatedance(repo, dest, orig.node(), None)
             tr.close() # to keep changes in this transaction (e.g. dirstate)
-        raise MergeFailure(_('unresolved merge conflicts '
-                             '(see hg help resolve)'))
+        raise error.InterventionRequired(_('unresolved merge conflicts '
+                                           '(see hg help resolve)'))
     nodenew = _relocatecommit(repo, orig, commitmsg)
     _finalizerelocate(repo, orig, dest, nodenew, tr, category, evolvestate)
     return nodenew