RF: keep_file_open == 'auto' now causes file handles to be kept open if

indexed_gzip is used, or dropped if gzip is used. Default value for
keep_file_open is now False. Warn that 'auto' will be deprecated soon.

Author: pauldmccarthy

nibabel/arrayproxy.py

@@ -51,8 +51,12 @@
 If this is set to any other value, attempts to create an ``ArrayProxy`` without
 specifying the ``keep_file_open`` flag will result in a ``ValueError`` being
 raised.
+
+.. warning:: Setting this flag to a value of ``'auto'`` will become deprecated
+             behaviour in version 2.4.0. Support for ``'auto'`` will be removed
+             in version 3.0.0.
 """
-KEEP_FILE_OPEN_DEFAULT = 'auto'
+KEEP_FILE_OPEN_DEFAULT = False
 
 
 class ArrayProxy(object):

nibabel/openers.py

@@ -90,8 +90,7 @@ def _gzip_open(filename, mode='rb', compresslevel=9, keep_open=False):
     # True, we tell IndexedGzipFile to keep the file handle open. Otherwise
     # the IndexedGzipFile will close/open the file on each read.
     if HAVE_INDEXED_GZIP and mode == 'rb':
-        gzip_file = IndexedGzipFile(
-            filename, drop_handles=keep_open is not True)
+        gzip_file = IndexedGzipFile(filename, drop_handles=not keep_open)
 
     # Fall-back to built-in GzipFile (wrapped with the BufferedGzipFile class
     # defined above)