Reverse order for parsing files in XDG_CONFIG_DIRS

https://specifications.freedesktop.org/basedir-spec/latest/
says precedence should be

XDG_CONFIG_HOME > 1st entry of XDG_CONFIG_DIRS > 2nd entry ...

EasyBuild had this reversed for XDG_CONFIG_DIRS

Fixes easybuilders#4582

easybuild/tools/options.py

@@ -123,7 +123,7 @@ def terminal_supports_colors(stream):
 CONFIG_ENV_VAR_PREFIX = 'EASYBUILD'
 
 XDG_CONFIG_HOME = os.environ.get('XDG_CONFIG_HOME', os.path.join(os.path.expanduser('~'), ".config"))
-XDG_CONFIG_DIRS = os.environ.get('XDG_CONFIG_DIRS', '/etc/xdg').split(os.pathsep)
+XDG_CONFIG_DIRS = os.environ.get('XDG_CONFIG_DIRS', '/etc/xdg').split(os.pathsep)[::-1]
 DEFAULT_SYS_CFGFILES = [f for d in XDG_CONFIG_DIRS for f in sorted(glob.glob(os.path.join(d, 'easybuild.d', '*.cfg')))]
 DEFAULT_USER_CFGFILE = os.path.join(XDG_CONFIG_HOME, 'easybuild', 'config.cfg')
 

test/framework/config.py

@@ -448,7 +448,7 @@ def test_XDG_CONFIG_env_vars(self):
 
         # $XDG_CONFIG_HOME not set, multiple directories listed in $XDG_CONFIG_DIRS
         del os.environ['XDG_CONFIG_HOME']  # unset, so should become default
-        os.environ['XDG_CONFIG_DIRS'] = os.pathsep.join([dir1, dir2, dir3])
+        os.environ['XDG_CONFIG_DIRS'] = os.pathsep.join([dir3, dir2, dir1])
         cfg_files = [
             os.path.join(dir1, 'easybuild.d', 'bar.cfg'),
             os.path.join(dir1, 'easybuild.d', 'foo.cfg'),

test/framework/options.py

@@ -3542,7 +3542,7 @@ def test_show_default_configfiles(self):
 
         xdg_config_home = os.path.join(self.test_prefix, 'home')
         os.environ['XDG_CONFIG_HOME'] = xdg_config_home
-        xdg_config_dirs = [os.path.join(self.test_prefix, 'etc', 'xdg'), os.path.join(self.test_prefix, 'moaretc')]
+        xdg_config_dirs = [os.path.join(self.test_prefix, 'moaretc'), os.path.join(self.test_prefix, 'etc', 'xdg')]
         os.environ['XDG_CONFIG_DIRS'] = os.pathsep.join(xdg_config_dirs)
 
         # put various dummy cfgfiles in place
@@ -3563,7 +3563,7 @@ def test_show_default_configfiles(self):
         logtxt = read_file(self.logfile)
         expected = expected_tmpl % (xdg_config_home, os.pathsep.join(xdg_config_dirs),
                                     "%s => found" % os.path.join(xdg_config_home, 'easybuild', 'config.cfg'),
-                                    '{' + ', '.join(xdg_config_dirs) + '}',
+                                    '{' + ', '.join(xdg_config_dirs[::-1]) + '}',
                                     ', '.join(cfgfiles[:-1]), 4, ', '.join(cfgfiles))
         self.assertIn(expected, logtxt)