diff --git a/hgdemandimport/__init__.py b/hgdemandimport/__init__.py
--- a/hgdemandimport/__init__.py
+++ b/hgdemandimport/__init__.py
@@ -15,10 +15,7 @@
 import os
 import sys
 
-if sys.version_info[0] >= 3:
-    from . import demandimportpy3 as demandimport
-else:
-    from . import demandimportpy2 as demandimport
+from . import demandimportpy3 as demandimport
 
 # Full module names which can't be lazy imported.
 # Extensions can add to this set.
diff --git a/hgdemandimport/demandimportpy2.py b/hgdemandimport/demandimportpy2.py
deleted file mode 100644
--- a/hgdemandimport/demandimportpy2.py
+++ /dev/null
@@ -1,325 +0,0 @@
-# demandimport.py - global demand-loading of modules for Mercurial
-#
-# Copyright 2006, 2007 Olivia Mackall <olivia@selenic.com>
-#
-# This software may be used and distributed according to the terms of the
-# GNU General Public License version 2 or any later version.
-
-'''
-demandimport - automatic demandloading of modules
-
-To enable this module, do:
-
-  import demandimport; demandimport.enable()
-
-Imports of the following forms will be demand-loaded:
-
-  import a, b.c
-  import a.b as c
-  from a import b,c # a will be loaded immediately
-
-These imports will not be delayed:
-
-  from a import *
-  b = __import__(a)
-'''
-
-
-import __builtin__ as builtins
-import contextlib
-import sys
-
-from . import tracing
-
-contextmanager = contextlib.contextmanager
-
-_origimport = __import__
-
-nothing = object()
-
-
-def _hgextimport(importfunc, name, globals, *args, **kwargs):
-    try:
-        return importfunc(name, globals, *args, **kwargs)
-    except ImportError:
-        if not globals:
-            raise
-        # extensions are loaded with "hgext_" prefix
-        hgextname = 'hgext_%s' % name
-        nameroot = hgextname.split('.', 1)[0]
-        contextroot = globals.get('__name__', '').split('.', 1)[0]
-        if nameroot != contextroot:
-            raise
-        # retry to import with "hgext_" prefix
-        return importfunc(hgextname, globals, *args, **kwargs)
-
-
-class _demandmod:
-    """module demand-loader and proxy
-
-    Specify 1 as 'level' argument at construction, to import module
-    relatively.
-    """
-
-    def __init__(self, name, globals, locals, level):
-        if '.' in name:
-            head, rest = name.split('.', 1)
-            after = [rest]
-        else:
-            head = name
-            after = []
-        object.__setattr__(
-            self, "_data", (head, globals, locals, after, level, set())
-        )
-        object.__setattr__(self, "_module", None)
-
-    def _extend(self, name):
-        """add to the list of submodules to load"""
-        self._data[3].append(name)
-
-    def _addref(self, name):
-        """Record that the named module ``name`` imports this module.
-
-        References to this proxy class having the name of this module will be
-        replaced at module load time. We assume the symbol inside the importing
-        module is identical to the "head" name of this module. We don't
-        actually know if "as X" syntax is being used to change the symbol name
-        because this information isn't exposed to __import__.
-        """
-        self._data[5].add(name)
-
-    def _load(self):
-        if not self._module:
-            with tracing.log('demandimport %s', self._data[0]):
-                head, globals, locals, after, level, modrefs = self._data
-                mod = _hgextimport(
-                    _origimport, head, globals, locals, None, level
-                )
-                if mod is self:
-                    # In this case, _hgextimport() above should imply
-                    # _demandimport(). Otherwise, _hgextimport() never
-                    # returns _demandmod. This isn't intentional behavior,
-                    # in fact. (see also issue5304 for detail)
-                    #
-                    # If self._module is already bound at this point, self
-                    # should be already _load()-ed while _hgextimport().
-                    # Otherwise, there is no way to import actual module
-                    # as expected, because (re-)invoking _hgextimport()
-                    # should cause same result.
-                    # This is reason why _load() returns without any more
-                    # setup but assumes self to be already bound.
-                    mod = self._module
-                    assert mod and mod is not self, "%s, %s" % (self, mod)
-                    return
-
-                # load submodules
-                def subload(mod, p):
-                    h, t = p, None
-                    if '.' in p:
-                        h, t = p.split('.', 1)
-                    if getattr(mod, h, nothing) is nothing:
-                        setattr(
-                            mod,
-                            h,
-                            _demandmod(p, mod.__dict__, mod.__dict__, level=1),
-                        )
-                    elif t:
-                        subload(getattr(mod, h), t)
-
-                for x in after:
-                    subload(mod, x)
-
-                # Replace references to this proxy instance with the
-                # actual module.
-                if locals:
-                    if locals.get(head) is self:
-                        locals[head] = mod
-                    elif locals.get(head + 'mod') is self:
-                        locals[head + 'mod'] = mod
-
-                for modname in modrefs:
-                    modref = sys.modules.get(modname, None)
-                    if modref and getattr(modref, head, None) is self:
-                        setattr(modref, head, mod)
-
-                object.__setattr__(self, "_module", mod)
-
-    def __repr__(self):
-        if self._module:
-            return "<proxied module '%s'>" % self._data[0]
-        return "<unloaded module '%s'>" % self._data[0]
-
-    def __call__(self, *args, **kwargs):
-        raise TypeError("%s object is not callable" % repr(self))
-
-    def __getattr__(self, attr):
-        self._load()
-        return getattr(self._module, attr)
-
-    def __setattr__(self, attr, val):
-        self._load()
-        setattr(self._module, attr, val)
-
-    @property
-    def __dict__(self):
-        self._load()
-        return self._module.__dict__
-
-    @property
-    def __doc__(self):
-        self._load()
-        return self._module.__doc__
-
-
-_pypy = '__pypy__' in sys.builtin_module_names
-
-
-def _demandimport(name, globals=None, locals=None, fromlist=None, level=-1):
-    if locals is None or name in ignores or fromlist == ('*',):
-        # these cases we can't really delay
-        return _hgextimport(_origimport, name, globals, locals, fromlist, level)
-    elif not fromlist:
-        # import a [as b]
-        if '.' in name:  # a.b
-            base, rest = name.split('.', 1)
-            # email.__init__ loading email.mime
-            if globals and globals.get('__name__', None) == base:
-                return _origimport(name, globals, locals, fromlist, level)
-            # if a is already demand-loaded, add b to its submodule list
-            if base in locals:
-                if isinstance(locals[base], _demandmod):
-                    locals[base]._extend(rest)
-                return locals[base]
-        return _demandmod(name, globals, locals, level)
-    else:
-        # There is a fromlist.
-        # from a import b,c,d
-        # from . import b,c,d
-        # from .a import b,c,d
-
-        # level == -1: relative and absolute attempted (Python 2 only).
-        # level >= 0: absolute only (Python 2 w/ absolute_import and Python 3).
-        # The modern Mercurial convention is to use absolute_import everywhere,
-        # so modern Mercurial code will have level >= 0.
-
-        # The name of the module the import statement is located in.
-        globalname = globals.get('__name__')
-
-        def processfromitem(mod, attr):
-            """Process an imported symbol in the import statement.
-
-            If the symbol doesn't exist in the parent module, and if the
-            parent module is a package, it must be a module. We set missing
-            modules up as _demandmod instances.
-            """
-            symbol = getattr(mod, attr, nothing)
-            nonpkg = getattr(mod, '__path__', nothing) is nothing
-            if symbol is nothing:
-                if nonpkg:
-                    # do not try relative import, which would raise ValueError,
-                    # and leave unknown attribute as the default __import__()
-                    # would do. the missing attribute will be detected later
-                    # while processing the import statement.
-                    return
-                mn = '%s.%s' % (mod.__name__, attr)
-                if mn in ignores:
-                    importfunc = _origimport
-                else:
-                    importfunc = _demandmod
-                symbol = importfunc(attr, mod.__dict__, locals, level=1)
-                setattr(mod, attr, symbol)
-
-            # Record the importing module references this symbol so we can
-            # replace the symbol with the actual module instance at load
-            # time.
-            if globalname and isinstance(symbol, _demandmod):
-                symbol._addref(globalname)
-
-        def chainmodules(rootmod, modname):
-            # recurse down the module chain, and return the leaf module
-            mod = rootmod
-            for comp in modname.split('.')[1:]:
-                obj = getattr(mod, comp, nothing)
-                if obj is nothing:
-                    obj = _demandmod(comp, mod.__dict__, mod.__dict__, level=1)
-                    setattr(mod, comp, obj)
-                elif mod.__name__ + '.' + comp in sys.modules:
-                    # prefer loaded module over attribute (issue5617)
-                    obj = sys.modules[mod.__name__ + '.' + comp]
-                mod = obj
-            return mod
-
-        if level >= 0:
-            if name:
-                # "from a import b" or "from .a import b" style
-                rootmod = _hgextimport(
-                    _origimport, name, globals, locals, level=level
-                )
-                mod = chainmodules(rootmod, name)
-            elif _pypy:
-                # PyPy's __import__ throws an exception if invoked
-                # with an empty name and no fromlist.  Recreate the
-                # desired behaviour by hand.
-                mn = globalname
-                mod = sys.modules[mn]
-                if getattr(mod, '__path__', nothing) is nothing:
-                    mn = mn.rsplit('.', 1)[0]
-                    mod = sys.modules[mn]
-                if level > 1:
-                    mn = mn.rsplit('.', level - 1)[0]
-                    mod = sys.modules[mn]
-            else:
-                mod = _hgextimport(
-                    _origimport, name, globals, locals, level=level
-                )
-
-            for x in fromlist:
-                processfromitem(mod, x)
-
-            return mod
-
-        # But, we still need to support lazy loading of standard library and 3rd
-        # party modules. So handle level == -1.
-        mod = _hgextimport(_origimport, name, globals, locals)
-        mod = chainmodules(mod, name)
-
-        for x in fromlist:
-            processfromitem(mod, x)
-
-        return mod
-
-
-ignores = set()
-
-
-def init(ignoreset):
-    global ignores
-    ignores = ignoreset
-
-
-def isenabled():
-    return builtins.__import__ == _demandimport
-
-
-def enable():
-    """enable global demand-loading of modules"""
-    builtins.__import__ = _demandimport
-
-
-def disable():
-    """disable global demand-loading of modules"""
-    builtins.__import__ = _origimport
-
-
-@contextmanager
-def deactivated():
-    """context manager for disabling demandimport in 'with' blocks"""
-    demandenabled = isenabled()
-    if demandenabled:
-        disable()
-
-    try:
-        yield
-    finally:
-        if demandenabled:
-            enable()
diff --git a/tests/test-check-py3-compat.t b/tests/test-check-py3-compat.t
--- a/tests/test-check-py3-compat.t
+++ b/tests/test-check-py3-compat.t
@@ -4,7 +4,6 @@
   $ cd "$TESTDIR"/..
 
   $ testrepohg files 'set:(**.py) - grep(pygments)' \
-  > -X hgdemandimport/demandimportpy2.py \
   > -X hgext/fsmonitor/pywatchman \
   > -X mercurial/cffi \
   > -X mercurial/thirdparty \