diff -r a3a36bcf122e -r 1858fc2327ef mercurial/templatekw.py
--- a/mercurial/templatekw.py	Sat Apr 22 20:29:45 2017 +0900
+++ b/mercurial/templatekw.py	Thu Jun 15 13:02:58 2017 +0200
@@ -18,6 +18,7 @@
     encoding,
     error,
     hbisect,
+    obsutil,
     patch,
     registrar,
     scmutil,
@@ -560,6 +561,16 @@
         return 'obsolete'
     return ''
 
+@templatekeyword("predecessors")
+def showpredecessors(repo, ctx, **args):
+    """Returns the list if the closest visible successors
+    """
+    predecessors = sorted(obsutil.closestpredecessors(repo, ctx.node()))
+    predecessors = map(hex, predecessors)
+
+    return _hybrid(None, predecessors, lambda x: {'predecessor': x},
+                   lambda d: d['predecessor'][:12])
+
 @templatekeyword('p1rev')
 def showp1rev(repo, ctx, templ, **args):
     """Integer. The repository-local revision number of the changeset's