diff --git a/mercurial/context.py b/mercurial/context.py
--- a/mercurial/context.py
+++ b/mercurial/context.py
@@ -233,15 +233,15 @@ class changectx(object):
 
     def obsolete(self):
         """True if the changeset is obsolete"""
-        return self.rev() in obsmod.getobscache(self._repo, 'obsolete')
+        return self.rev() in obsmod.getrevs(self._repo, 'obsolete')
 
     def extinct(self):
         """True if the changeset is extinct"""
-        return self.rev() in obsmod.getobscache(self._repo, 'extinct')
+        return self.rev() in obsmod.getrevs(self._repo, 'extinct')
 
     def unstable(self):
         """True if the changeset is not obsolete but it's ancestor are"""
-        return self.rev() in obsmod.getobscache(self._repo, 'unstable')
+        return self.rev() in obsmod.getrevs(self._repo, 'unstable')
 
     def _fileinfo(self, path):
         if '_manifest' in self.__dict__:
diff --git a/mercurial/obsolete.py b/mercurial/obsolete.py
--- a/mercurial/obsolete.py
+++ b/mercurial/obsolete.py
@@ -376,7 +376,7 @@ def cachefor(name):
         return func
     return decorator
 
-def getobscache(repo, name):
+def getrevs(repo, name):
     """Return the set of revision that belong to the <name> set
 
     Such access may compute the set and cache it for future use"""
diff --git a/mercurial/revset.py b/mercurial/revset.py
--- a/mercurial/revset.py
+++ b/mercurial/revset.py
@@ -622,7 +622,7 @@ def extinct(repo, subset, x):
     """
     # i18n: "extinct" is a keyword
     getargs(x, 0, 0, _("extinct takes no arguments"))
-    extincts = obsmod.getobscache(repo, 'extinct')
+    extincts = obsmod.getrevs(repo, 'extinct')
     return [r for r in subset if r in extincts]
 
 def extra(repo, subset, x):
@@ -977,7 +977,7 @@ def obsolete(repo, subset, x):
     Mutable changeset with a newer version."""
     # i18n: "obsolete" is a keyword
     getargs(x, 0, 0, _("obsolete takes no arguments"))
-    obsoletes = obsmod.getobscache(repo, 'obsolete')
+    obsoletes = obsmod.getrevs(repo, 'obsolete')
     return [r for r in subset if r in obsoletes]
 
 def origin(repo, subset, x):
@@ -1456,7 +1456,7 @@ def unstable(repo, subset, x):
     """
     # i18n: "unstable" is a keyword
     getargs(x, 0, 0, _("unstable takes no arguments"))
-    unstables = obsmod.getobscache(repo, 'unstable')
+    unstables = obsmod.getrevs(repo, 'unstable')
     return [r for r in subset if r in unstables]