diff --git a/hgext/parentrevspec.py b/hgext/parentrevspec.py
deleted file mode 100644
--- a/hgext/parentrevspec.py
+++ /dev/null
@@ -1,96 +0,0 @@
-# Mercurial extension to make it easy to refer to the parent of a revision
-#
-# Copyright (C) 2007 Alexis S. L. Carvalho <alexis@cecm.usp.br>
-#
-# This software may be used and distributed according to the terms of the
-# GNU General Public License version 2 or any later version.
-
-'''interpret suffixes to refer to ancestor revisions
-
-This extension allows you to use git-style suffixes to refer to the
-ancestors of a specific revision.
-
-For example, if you can refer to a revision as "foo", then::
-
-  foo^N = Nth parent of foo
-  foo^0 = foo
-  foo^1 = first parent of foo
-  foo^2 = second parent of foo
-  foo^  = foo^1
-
-  foo~N = Nth first grandparent of foo
-  foo~0 = foo
-  foo~1 = foo^1 = foo^ = first parent of foo
-  foo~2 = foo^1^1 = foo^^ = first parent of first parent of foo
-'''
-from mercurial import error
-
-def reposetup(ui, repo):
-    if not repo.local():
-        return
-
-    class parentrevspecrepo(repo.__class__):
-        def lookup(self, key):
-            try:
-                _super = super(parentrevspecrepo, self)
-                return _super.lookup(key)
-            except error.RepoError:
-                pass
-
-            circ = key.find('^')
-            tilde = key.find('~')
-            if circ < 0 and tilde < 0:
-                raise
-            elif circ >= 0 and tilde >= 0:
-                end = min(circ, tilde)
-            else:
-                end = max(circ, tilde)
-
-            cl = self.changelog
-            base = key[:end]
-            try:
-                node = _super.lookup(base)
-            except error.RepoError:
-                # eek - reraise the first error
-                return _super.lookup(key)
-
-            rev = cl.rev(node)
-            suffix = key[end:]
-            i = 0
-            while i < len(suffix):
-                # foo^N => Nth parent of foo
-                # foo^0 == foo
-                # foo^1 == foo^ == 1st parent of foo
-                # foo^2 == 2nd parent of foo
-                if suffix[i] == '^':
-                    j = i + 1
-                    p = cl.parentrevs(rev)
-                    if j < len(suffix) and suffix[j].isdigit():
-                        j += 1
-                        n = int(suffix[i + 1:j])
-                        if n > 2 or n == 2 and p[1] == -1:
-                            raise
-                    else:
-                        n = 1
-                    if n:
-                        rev = p[n - 1]
-                    i = j
-                # foo~N => Nth first grandparent of foo
-                # foo~0 = foo
-                # foo~1 = foo^1 == foo^ == 1st parent of foo
-                # foo~2 = foo^1^1 == foo^^ == 1st parent of 1st parent of foo
-                elif suffix[i] == '~':
-                    j = i + 1
-                    while j < len(suffix) and suffix[j].isdigit():
-                        j += 1
-                    if j == i + 1:
-                        raise
-                    n = int(suffix[i + 1:j])
-                    for k in xrange(n):
-                        rev = cl.parentrevs(rev)[0]
-                    i = j
-                else:
-                    raise
-            return cl.node(rev)
-
-    repo.__class__ = parentrevspecrepo
diff --git a/mercurial/extensions.py b/mercurial/extensions.py
--- a/mercurial/extensions.py
+++ b/mercurial/extensions.py
@@ -11,7 +11,7 @@ from i18n import _, gettext
 
 _extensions = {}
 _order = []
-_ignore = ['hbisect', 'bookmarks']
+_ignore = ['hbisect', 'bookmarks', 'parentrevspec']
 
 def extensions():
     for name in _order:
diff --git a/tests/test-parentrevspec.t b/tests/test-parentrevspec.t
deleted file mode 100644
--- a/tests/test-parentrevspec.t
+++ /dev/null
@@ -1,105 +0,0 @@
-
-  $ commit()
-  > {
-  >     msg=$1
-  >     p1=$2
-  >     p2=$3
-  > 
-  >     if [ "$p1" ]; then
-  >         hg up -qC $p1
-  >     fi
-  > 
-  >     if [ "$p2" ]; then
-  >         HGMERGE=true hg merge -q $p2
-  >     fi
-  > 
-  >     echo >> foo
-  > 
-  >     hg commit -qAm "$msg"
-  > }
-  $ hg init repo
-  $ cd repo
-  $ echo '[extensions]' > .hg/hgrc
-  $ echo 'parentrevspec =' >> .hg/hgrc
-  $ commit '0: add foo'
-  $ commit '1: change foo 1'
-  $ commit '2: change foo 2a'
-  $ commit '3: change foo 3a'
-  $ commit '4: change foo 2b' 1
-  $ commit '5: merge' 3 4
-  $ commit '6: change foo again'
-  $ hg log --template '{rev}:{node|short} {parents}\n'
-  6:755d1e0d79e9 
-  5:9ce2ce29723a 3:a3e00c7dbf11 4:bb4475edb621 
-  4:bb4475edb621 1:5d953a1917d1 
-  3:a3e00c7dbf11 
-  2:befc7d89d081 
-  1:5d953a1917d1 
-  0:837088b6e1d9 
-  $ echo
-  
-  $ lookup()
-  > {
-  >     for rev in "$@"; do
-  >         printf "$rev: "
-  >         hg id -nr $rev
-  >     done
-  >     true
-  > }
-  $ tipnode=`hg id -ir tip`
-
-should work with tag/branch/node/rev
-
-  $ for r in tip default $tipnode 6; do
-  >     lookup "$r^"
-  > done
-  tip^: 5
-  default^: 5
-  755d1e0d79e9^: 5
-  6^: 5
-  $ echo
-  
-
-some random lookups
-
-  $ lookup "6^^" "6^^^" "6^^^^" "6^^^^^" "6^^^^^^" "6^1" "6^2" "6^^2" "6^1^2" "6^^3"
-  6^^: 3
-  6^^^: 2
-  6^^^^: 1
-  6^^^^^: 0
-  6^^^^^^: -1
-  6^1: 5
-  6^2: hg: parse error at 1: syntax error
-  6^^2: 4
-  6^1^2: 4
-  6^^3: hg: parse error at 1: syntax error
-  $ lookup "6~" "6~1" "6~2" "6~3" "6~4" "6~5" "6~42" "6~1^2" "6~1^2~2"
-  6~: hg: parse error at 1: syntax error
-  6~1: 5
-  6~2: 3
-  6~3: 2
-  6~4: 1
-  6~5: 0
-  6~42: -1
-  6~1^2: 4
-  6~1^2~2: 0
-  $ echo
-  
-
-with a tag "6^" pointing to rev 1
-
-  $ hg tag -l -r 1 "6^"
-  $ lookup "6^" "6^1" "6~1" "6^^"
-  6^: 1
-  6^1: 5
-  6~1: 5
-  6^^: 3
-  $ echo
-  
-
-with a tag "foo^bar" pointing to rev 2
-
-  $ hg tag -l -r 2 "foo^bar"
-  $ lookup "foo^bar" "foo^bar^"
-  foo^bar: 2
-  foo^bar^: hg: parse error at 3: syntax error