diff --git a/mercurial/util.py b/mercurial/util.py
--- a/mercurial/util.py
+++ b/mercurial/util.py
@@ -1001,6 +1001,12 @@ if os.name == 'nt':
             _quotere = re.compile(r'(\\*)("|\\$)')
         return '"%s"' % _quotere.sub(r'\1\1\\\2', s)
 
+    def quotecommand(cmd):
+        """Build a command string suitable for os.popen* calls."""
+        # The extra quotes are needed because popen* runs the command
+        # through the current COMSPEC. cmd.exe suppress enclosing quotes.
+        return '"' + cmd + '"'
+
     def explain_exit(code):
         return _("exited with status %d") % code, code
 
@@ -1154,6 +1160,9 @@ else:
         else:
             return "'%s'" % s.replace("'", "'\\''")
 
+    def quotecommand(cmd):
+        return cmd
+
     def testpid(pid):
         '''return False if pid dead, True if running or not sure'''
         if os.sys.platform == 'OpenVMS':
@@ -1681,3 +1690,7 @@ def drop_scheme(scheme, path):
         if path.startswith('//'):
             path = path[2:]
     return path
+
+def uirepr(s):
+    # Avoid double backslash in Windows path repr()
+    return repr(s).replace('\\\\', '\\')