config: don't read the same config file twice

In some cases some config files would be read twice and shown twice in
showconfig --debug.

mercurial/scmposix.py

@@ -1,32 +1,33
 import sys, os
 import osutil
 
 def _rcfiles(path):
     rcs = [os.path.join(path, 'hgrc')]
     rcdir = os.path.join(path, 'hgrc.d')
     try:
         rcs.extend([os.path.join(rcdir, f)
                     for f, kind in osutil.listdir(rcdir)
                     if f.endswith(".rc")])
     except OSError:
         pass
     return rcs
 
 def systemrcpath():
     path = []
     if sys.platform == 'plan9':
         root = 'lib/mercurial'
     else:
         root = 'etc/mercurial'
     # old mod_python does not set sys.argv
     if len(getattr(sys, 'argv', [])) > 0:
         p = os.path.dirname(os.path.dirname(sys.argv[0]))
-        path.extend(_rcfiles(os.path.join(p, root)))
+        if p != '/':
+            path.extend(_rcfiles(os.path.join(p, root)))
     path.extend(_rcfiles('/' + root))
     return path
 
 def userrcpath():
     if sys.platform == 'plan9':
         return [os.environ['home'] + '/lib/hgrc']
     else:
         return [os.path.expanduser('~/.hgrc')]

mercurial/scmwindows.py

@@ -1,46 +1,46
 import os
 import osutil
 import util
 import _winreg
 
 def systemrcpath():
     '''return default os-specific hgrc search path'''
     rcpath = []
     filename = util.executablepath()
     # Use mercurial.ini found in directory with hg.exe
     progrc = os.path.join(os.path.dirname(filename), 'mercurial.ini')
     if os.path.isfile(progrc):
         rcpath.append(progrc)
         return rcpath
     # Use hgrc.d found in directory with hg.exe
     progrcd = os.path.join(os.path.dirname(filename), 'hgrc.d')
     if os.path.isdir(progrcd):
         for f, kind in osutil.listdir(progrcd):
             if f.endswith('.rc'):
                 rcpath.append(os.path.join(progrcd, f))
         return rcpath
     # else look for a system rcpath in the registry
     value = util.lookupreg('SOFTWARE\\Mercurial', None,
                            _winreg.HKEY_LOCAL_MACHINE)
     if not isinstance(value, str) or not value:
         return rcpath
     value = util.localpath(value)
     for p in value.split(os.pathsep):
         if p.lower().endswith('mercurial.ini'):
             rcpath.append(p)
         elif os.path.isdir(p):
             for f, kind in osutil.listdir(p):
                 if f.endswith('.rc'):
                     rcpath.append(os.path.join(p, f))
     return rcpath
 
 def userrcpath():
     '''return os-specific hgrc search path to the user dir'''
     home = os.path.expanduser('~')
     path = [os.path.join(home, 'mercurial.ini'),
             os.path.join(home, '.hgrc')]
     userprofile = os.environ.get('USERPROFILE')
-    if userprofile:
+    if userprofile and userprofile != home:
         path.append(os.path.join(userprofile, 'mercurial.ini'))
         path.append(os.path.join(userprofile, '.hgrc'))
     return path