diff --git a/contrib/python3-whitelist b/contrib/python3-whitelist
--- a/contrib/python3-whitelist
+++ b/contrib/python3-whitelist
@@ -9,7 +9,6 @@
 test-check-shbang.t
 test-contrib-check-code.t
 test-contrib-check-commit.t
-test-ctxmanager.py
 test-diff-issue2761.t
 test-diff-newlines.t
 test-diff-reverse.t
diff --git a/mercurial/util.py b/mercurial/util.py
--- a/mercurial/util.py
+++ b/mercurial/util.py
@@ -3052,66 +3052,6 @@
         yield path[:pos]
         pos = path.rfind('/', 0, pos)
 
-class ctxmanager(object):
-    '''A context manager for use in 'with' blocks to allow multiple
-    contexts to be entered at once.  This is both safer and more
-    flexible than contextlib.nested.
-
-    Once Mercurial supports Python 2.7+, this will become mostly
-    unnecessary.
-    '''
-
-    def __init__(self, *args):
-        '''Accepts a list of no-argument functions that return context
-        managers.  These will be invoked at __call__ time.'''
-        self._pending = args
-        self._atexit = []
-
-    def __enter__(self):
-        return self
-
-    def enter(self):
-        '''Create and enter context managers in the order in which they were
-        passed to the constructor.'''
-        values = []
-        for func in self._pending:
-            obj = func()
-            values.append(obj.__enter__())
-            self._atexit.append(obj.__exit__)
-        del self._pending
-        return values
-
-    def atexit(self, func, *args, **kwargs):
-        '''Add a function to call when this context manager exits.  The
-        ordering of multiple atexit calls is unspecified, save that
-        they will happen before any __exit__ functions.'''
-        def wrapper(exc_type, exc_val, exc_tb):
-            func(*args, **kwargs)
-        self._atexit.append(wrapper)
-        return func
-
-    def __exit__(self, exc_type, exc_val, exc_tb):
-        '''Context managers are exited in the reverse order from which
-        they were created.'''
-        received = exc_type is not None
-        suppressed = False
-        pending = None
-        self._atexit.reverse()
-        for exitfunc in self._atexit:
-            try:
-                if exitfunc(exc_type, exc_val, exc_tb):
-                    suppressed = True
-                    exc_type = None
-                    exc_val = None
-                    exc_tb = None
-            except BaseException:
-                pending = sys.exc_info()
-                exc_type, exc_val, exc_tb = pending = sys.exc_info()
-        del self._atexit
-        if pending:
-            raise exc_val
-        return received and suppressed
-
 # compression code
 
 SERVERROLE = 'server'
diff --git a/tests/test-check-module-imports.t b/tests/test-check-module-imports.t
--- a/tests/test-check-module-imports.t
+++ b/tests/test-check-module-imports.t
@@ -24,7 +24,6 @@
   > -X i18n/posplit \
   > -X tests/test-hgweb-auth.py \
   > -X tests/hypothesishelpers.py \
-  > -X tests/test-ctxmanager.py \
   > -X tests/test-lock.py \
   > -X tests/test-verify-repo-operations.py \
   > -X tests/test-hook.t \
diff --git a/tests/test-ctxmanager.py b/tests/test-ctxmanager.py
deleted file mode 100644
--- a/tests/test-ctxmanager.py
+++ /dev/null
@@ -1,77 +0,0 @@
-from __future__ import absolute_import
-
-import silenttestrunner
-import unittest
-
-from mercurial import util
-
-class contextmanager(object):
-    def __init__(self, name, trace):
-        self.name = name
-        self.entered = False
-        self.exited = False
-        self.trace = trace
-
-    def __enter__(self):
-        self.entered = True
-        self.trace(('enter', self.name))
-        return self
-
-    def __exit__(self, exc_type, exc_val, exc_tb):
-        self.exited = exc_type, exc_val, exc_tb
-        self.trace(('exit', self.name))
-
-    def __repr__(self):
-        return '<ctx %r>' % self.name
-
-class ctxerror(Exception):
-    pass
-
-class raise_on_enter(contextmanager):
-    def __enter__(self):
-        self.trace(('raise', self.name))
-        raise ctxerror(self.name)
-
-class raise_on_exit(contextmanager):
-    def __exit__(self, exc_type, exc_val, exc_tb):
-        self.trace(('raise', self.name))
-        raise ctxerror(self.name)
-
-def ctxmgr(name, trace):
-    return lambda: contextmanager(name, trace)
-
-class test_ctxmanager(unittest.TestCase):
-    def test_basics(self):
-        trace = []
-        addtrace = trace.append
-        with util.ctxmanager(ctxmgr('a', addtrace), ctxmgr('b', addtrace)) as c:
-            a, b = c.enter()
-            c.atexit(addtrace, ('atexit', 'x'))
-            c.atexit(addtrace, ('atexit', 'y'))
-        self.assertEqual(trace, [('enter', 'a'), ('enter', 'b'),
-                                 ('atexit', 'y'), ('atexit', 'x'),
-                                 ('exit', 'b'), ('exit', 'a')])
-
-    def test_raise_on_enter(self):
-        trace = []
-        addtrace = trace.append
-        with self.assertRaises(ctxerror):
-            with util.ctxmanager(ctxmgr('a', addtrace),
-                                 lambda: raise_on_enter('b', addtrace)) as c:
-                c.enter()
-                addtrace('unreachable')
-        self.assertEqual(trace, [('enter', 'a'), ('raise', 'b'), ('exit', 'a')])
-
-    def test_raise_on_exit(self):
-        trace = []
-        addtrace = trace.append
-        with self.assertRaises(ctxerror):
-            with util.ctxmanager(ctxmgr('a', addtrace),
-                                 lambda: raise_on_exit('b', addtrace)) as c:
-                c.enter()
-                addtrace('running')
-        self.assertEqual(trace, [('enter', 'a'), ('enter', 'b'), 'running',
-                                 ('raise', 'b'), ('exit', 'a')])
-
-if __name__ == '__main__':
-    silenttestrunner.main(__name__)