tree 96ec1e59265e883d472ff23437bb5200825ee244
parent 64263dfd182da4984c51ea33ebd597369d4196f3
author Neil Schemenauer <nas-github@arctrix.com> 1504581518 -0700
committer GitHub <noreply@github.com> 1504581518 -0700

bpo-17852: Maintain a list of BufferedWriter objects.  Flush them on exit. (#1908)

* Maintain a list of BufferedWriter objects.  Flush them on exit.

In Python 3, the buffer and the underlying file object are separate
and so the order in which objects are finalized matters.  This is
unlike Python 2 where the file and buffer were a single object and
finalization was done for both at the same time.  In Python 3, if
the file is finalized and closed before the buffer then the data in
the buffer is lost.

This change adds a doubly linked list of open file buffers.  An atexit
hook ensures they are flushed before proceeding with interpreter
shutdown.  This is addition does not remove the need to properly close
files as there are other reasons why buffered data could get lost during
finalization.

Initial patch by Armin Rigo.

* Use weakref.WeakSet instead of WeakKeyDictionary.

* Simplify buffered double-linked list types.

* In _flush_all_writers(), suppress errors from flush().

* Remove NEWS entry, use blurb.