--- a/hgext3rd/evolve/evolvecmd.py	Mon Mar 19 14:03:41 2018 +0100
+++ b/hgext3rd/evolve/evolvecmd.py	Sun Mar 18 01:27:02 2018 +0530
@@ -91,10 +91,14 @@
     pctx = orig.p1()
     keepbranch = orig.p1().branch() != orig.branch()
     if len(orig.parents()) == 2:
-        if not pctx.obsolete():
+        p1obs = orig.p1().obsolete()
+        p2obs = orig.p2().obsolete()
+        if not p1obs and p2obs:
             pctx = orig.p2()  # second parent is obsolete ?
             keepbranch = orig.p2().branch() != orig.branch()
-        elif orig.p2().obsolete():
+        elif not p2obs and p1obs:
+            pass
+        else:
             hint = _("Redo the merge (%s) and use `hg prune <old> "
                      "--succ <new>` to obsolete the old one") % orig.hex()[:12]
             ui.warn(_("warning: no support for evolving merge changesets "