--- a/mercurial/templatekw.py	Mon Oct 02 07:18:24 2017 +0100
+++ b/mercurial/templatekw.py	Sat Sep 09 19:13:25 2017 +0900
@@ -78,13 +78,18 @@
     value. Use unwrapvalue() or unwraphybrid() to obtain the inner object.
     """
 
-    def __init__(self, gen, value, makemap):
-        self.gen = gen
+    def __init__(self, gen, key, value, makemap):
+        if gen is not None:
+            self.gen = gen  # generator or function returning generator
+        self._key = key
         self._value = value  # may be generator of strings
         self._makemap = makemap
 
+    def gen(self):
+        yield pycompat.bytestr(self._value)
+
     def tomap(self):
-        return self._makemap()
+        return self._makemap(self._key)
 
     def itermaps(self):
         yield self.tomap()
@@ -114,6 +119,20 @@
         return thing
     return thing._value
 
+def wraphybridvalue(container, key, value):
+    """Wrap an element of hybrid container to be mappable
+
+    The key is passed to the makemap function of the given container, which
+    should be an item generated by iter(container).
+    """
+    makemap = getattr(container, '_makemap', None)
+    if makemap is None:
+        return value
+    if util.safehasattr(value, '_makemap'):
+        # a nested hybrid list/dict, which has its own way of map operation
+        return value
+    return _mappable(None, key, value, makemap)
+
 def showdict(name, data, mapping, plural=None, key='key', value='value',
              fmt='%s=%s', separator=' '):
     c = [{key: k, value: v} for k, v in data.iteritems()]
@@ -578,7 +597,7 @@
     f = templ('manifest', **args)
     # TODO: perhaps 'ctx' should be dropped from mapping because manifest
     # rev and node are completely different from changeset's.
-    return _mappable(f, f, lambda: {'rev': mrev, 'node': mhex})
+    return _mappable(f, None, f, lambda x: {'rev': mrev, 'node': mhex})
 
 def shownames(namespace, **args):
     """helper method to generate a template keyword for a namespace"""