Respect the process umask when creating the cache directory

diskcache/core.py

@@ -444,7 +444,11 @@ def __init__(self, directory=None, timeout=60, disk=Disk, **settings):
 
         if not op.isdir(directory):
             try:
-                os.makedirs(directory, 0o755)
+                # Let the OS apply the umask to the default mode rather than
+                # hard-coding 0o755, so the cache directory's permissions
+                # honor the caller's umask like any other newly created
+                # directory would.
+                os.makedirs(directory)
             except OSError as error:
                 if error.errno != errno.EEXIST:
                     raise EnvironmentError(

tests/test_core.py

@@ -144,6 +144,23 @@ def test_init_makedirs():
             raise
 
 
+def test_init_makedirs_respects_umask():
+    cache_dir = tempfile.mkdtemp()
+    shutil.rmtree(cache_dir)
+    makedirs = mock.Mock(wraps=os.makedirs)
+
+    try:
+        with mock.patch('os.makedirs', makedirs):
+            cache = dc.Cache(cache_dir)
+        cache.close()
+    finally:
+        shutil.rmtree(cache_dir, ignore_errors=True)
+
+    # No explicit mode should be passed, so the OS applies the umask to the
+    # default mode like it does for any other new directory.
+    makedirs.assert_called_once_with(cache_dir)
+
+
 def test_pragma_error(cache):
     local = mock.Mock()
     con = mock.Mock()