Fix matplotlib#2300: deal with the case where there are no writable directories.

Author: mdboom

lib/matplotlib/__init__.py

@@ -532,7 +532,11 @@ def _get_xdg_config_dir():
     base directory spec
     <http://standards.freedesktop.org/basedir-spec/basedir-spec-latest.html>`_.
     """
-    return os.environ.get('XDG_CONFIG_HOME', os.path.join(get_home(), '.config'))
+    home = get_home()
+    if home is None:
+        return None
+    else:
+        return os.environ.get('XDG_CONFIG_HOME', os.path.join(home, '.config'))
 
 
 def _get_xdg_cache_dir():
@@ -541,7 +545,11 @@ def _get_xdg_cache_dir():
     base directory spec
     <http://standards.freedesktop.org/basedir-spec/basedir-spec-latest.html>`_.
     """
-    return os.environ.get('XDG_CACHE_HOME', os.path.join(get_home(), '.cache'))
+    home = get_home()
+    if home is None:
+        return None
+    else:
+        return os.environ.get('XDG_CACHE_HOME', os.path.join(home, '.cache'))
 
 
 def _get_config_or_cache_dir(xdg_base):
@@ -557,22 +565,28 @@ def _get_config_or_cache_dir(xdg_base):
             return _create_tmp_config_dir()
         return configdir
 
+    p = None
     h = get_home()
-    p = os.path.join(h, '.matplotlib')
-    if (sys.platform.startswith('linux') and
-        not os.path.exists(p)):
-        p = os.path.join(xdg_base, 'matplotlib')
-
-    if os.path.exists(p):
-        if not _is_writable_dir(p):
-            return _create_tmp_config_dir()
-    else:
-        try:
-            mkdirs(p)
-        except OSError:
-            return _create_tmp_config_dir()
+    if h is not None:
+        p = os.path.join(h, '.matplotlib')
+        if (sys.platform.startswith('linux') and
+            not os.path.exists(p) and
+            xdg_base is not None):
+            p = os.path.join(xdg_base, 'matplotlib')
+
+    if p is not None:
+        if os.path.exists(p):
+            if _is_writable_dir(p):
+                return p
+        else:
+            try:
+                mkdirs(p)
+            except OSError:
+                pass
+            else:
+                return p
 
-    return p
+    return _create_tmp_config_dir()
 
 
 def _get_configdir():
@@ -728,9 +742,11 @@ def matplotlib_fname():
     if configdir is not None:
         fname = os.path.join(configdir, 'matplotlibrc')
         if os.path.exists(fname):
+            home = get_home()
             if (sys.platform.startswith('linux') and
+                home is not None and
                 fname == os.path.join(
-                    get_home(), '.matplotlib', 'matplotlibrc')):
+                    home, '.matplotlib', 'matplotlibrc')):
                 warnings.warn(
                     "Found matplotlib configuration in ~/.matplotlib/. "
                     "To conform with the XDG base directory standard, "

lib/matplotlib/font_manager.py

@@ -1324,15 +1324,15 @@ def findfont(prop, fontext='ttf'):
         return result
 
 else:
+    _fmcache = None
+
     if not 'TRAVIS' in os.environ:
         cachedir = get_cachedir()
         if cachedir is not None:
             if sys.version_info[0] >= 3:
                 _fmcache = os.path.join(cachedir, 'fontList.py3k.cache')
             else:
                 _fmcache = os.path.join(cachedir, 'fontList.cache')
-    else:
-        _fmcache = None
 
     fontManager = None