diff --git a/mercurial/namespaces.py b/mercurial/namespaces.py
--- a/mercurial/namespaces.py
+++ b/mercurial/namespaces.py
@@ -93,7 +93,7 @@
             def generatekw(context, mapping):
                 return templatekw.shownames(context, mapping, namespace.name)
 
-    def singlenode(self, repo, name):
+    def nodes(self, repo, name, allowmultiple=False):
         """
         Return the 'best' node for the given name. Best means the first node
         in the first nonempty list returned by a name-to-nodes mapping function
@@ -104,12 +104,12 @@
         for ns, v in self._names.iteritems():
             n = v.namemap(repo, name)
             if n:
+                if (allowmultiple and v.multinode) or len(n) == 1:
+                    return n
                 # return max revision number
-                if len(n) > 1:
-                    cl = repo.changelog
-                    maxrev = max(cl.rev(node) for node in n)
-                    return cl.node(maxrev)
-                return n[0]
+                cl = repo.changelog
+                maxrev = max(cl.rev(node) for node in n)
+                return [cl.node(maxrev)]
         raise KeyError(_('no such name: %s') % name)
 
 class namespace(object):
@@ -142,7 +142,7 @@
 
     def __init__(self, name, templatename=None, logname=None, colorname=None,
                  logfmt=None, listnames=None, namemap=None, nodemap=None,
-                 deprecated=None, builtin=False):
+                 deprecated=None, builtin=False, multinode=False):
         """create a namespace
 
         name: the namespace to be registered (in plural form)
@@ -158,6 +158,9 @@
         nodemap: function that inputs a node, output name(s)
         deprecated: set of names to be masked for ordinary use
         builtin: whether namespace is implemented by core Mercurial
+        multinode: whether namespace can have multiple nodes associated with
+                   one name (`hg log -r that-name` will then list multiple
+                   nodes)
         """
         self.name = name
         self.templatename = templatename
@@ -187,6 +190,7 @@
             self.deprecated = deprecated
 
         self.builtin = builtin
+        self.multinode = multinode
 
     def names(self, repo, node):
         """method that returns a (sorted) list of names in a namespace that
diff --git a/mercurial/revset.py b/mercurial/revset.py
--- a/mercurial/revset.py
+++ b/mercurial/revset.py
@@ -118,11 +118,14 @@
 def stringset(repo, subset, x, order):
     if not x:
         raise error.ParseError(_("empty string is not a valid revision"))
-    x = scmutil.intrev(scmutil.revsymbol(repo, x))
-    if (x in subset
-        or x == node.nullrev and isinstance(subset, fullreposet)):
-        return baseset([x])
-    return baseset()
+    ctxs = scmutil.revsymbolmultiple(repo, x)
+    if len(ctxs) == 1:
+        x = scmutil.intrev(ctxs[0])
+        if (x in subset
+            or x == node.nullrev and isinstance(subset, fullreposet)):
+            return baseset([x])
+        return baseset()
+    return subset & baseset(sorted(ctx.rev() for ctx in ctxs))
 
 def rangeset(repo, subset, x, y, order):
     m = getset(repo, fullreposet(repo), x)
diff --git a/mercurial/scmutil.py b/mercurial/scmutil.py
--- a/mercurial/scmutil.py
+++ b/mercurial/scmutil.py
@@ -488,7 +488,7 @@
     except error.RepoLookupError:
         return False
 
-def _revsymbol(repo, symbol):
+def _revsymbol(repo, symbol, allowmultiple):
     if not isinstance(symbol, bytes):
         msg = ("symbol (%s of type %s) was not a string, did you mean "
                "repo[symbol]?" % (symbol, type(symbol)))
@@ -524,9 +524,9 @@
 
         # look up bookmarks through the name interface
         try:
-            node = repo.names.singlenode(repo, symbol)
-            rev = repo.changelog.rev(node)
-            return [repo[rev]]
+            nodes = repo.names.nodes(repo, symbol, allowmultiple)
+            revs = [repo.changelog.rev(n) for n in nodes]
+            return [repo[r2] for r2 in revs] # "r2" to keep pyflakes happy
         except KeyError:
             pass
 
@@ -550,10 +550,19 @@
     i.e. things like ".", "tip", "1234", "deadbeef", "my-bookmark" work, but
     not "max(public())".
     """
-    ctxs = _revsymbol(repo, symbol)
+    ctxs = _revsymbol(repo, symbol, allowmultiple=False)
     assert len(ctxs) == 1
     return ctxs[0]
 
+def revsymbolmultiple(repo, symbol):
+    """Returns all contexts given a single revision symbol (as string).
+
+    This is similar to revsymbol(), but if "symbol" is a namespace symbol,
+    then this may return many context (if the namespace maps the symbol to
+    many revisions).
+    """
+    return _revsymbol(repo, symbol, allowmultiple=True)
+
 def _filterederror(repo, changeid):
     """build an exception to be raised about a filtered changeid
 
diff --git a/tests/paritynamesext.py b/tests/paritynamesext.py
new file mode 100644
--- /dev/null
+++ b/tests/paritynamesext.py
@@ -0,0 +1,26 @@
+# Defines a namespace with names 'even' and 'odd'
+
+from __future__ import absolute_import
+
+from mercurial import (
+    namespaces,
+)
+
+def reposetup(ui, repo):
+    def namemap(repo, name):
+        if name == 'even':
+            parity = 0
+        elif name == 'odd':
+            parity = 1
+        else:
+            return []
+        return [repo[rev].node() for rev in repo if rev % 2 == parity]
+    def nodemap(repo, node):
+        return [repo[node].rev() % 2]
+
+    ns = namespaces.namespace(b'parity', templatename=b'parity',
+                              logname=b'parity',
+                              listnames=lambda r: ['even', 'odd'],
+                              namemap=namemap, nodemap=nodemap,
+                              multinode=True)
+    repo.names.addnamespace(ns)
diff --git a/tests/test-revset2.t b/tests/test-revset2.t
--- a/tests/test-revset2.t
+++ b/tests/test-revset2.t
@@ -675,6 +675,12 @@
   6
   $ log 'named("tags")'
   6
+  $ hg --config extensions.revnamesext=$TESTDIR/paritynamesext.py log --template '{rev}\n' -r even
+  0
+  2
+  4
+  6
+  8
 
 issue2437