[Python-checkins] bpo-17852: Revert incorrect fix based on misunderstanding of _Py_PyAtExit() semantics (#4826)
Victor Stinner
webhook-mailer at python.org
Tue Dec 12 19:39:30 EST 2017
https://github.com/python/cpython/commit/317def9fdb29893df1ab380d396fcdd2eafe0588
commit: 317def9fdb29893df1ab380d396fcdd2eafe0588
branch: master
author: Antoine Pitrou <pitrou at free.fr>
committer: Victor Stinner <victor.stinner at gmail.com>
date: 2017-12-13T01:39:26+01:00
summary:
bpo-17852: Revert incorrect fix based on misunderstanding of _Py_PyAtExit() semantics (#4826)
files:
A Misc/NEWS.d/next/Library/2017-12-13-00-00-37.bpo-17852.Q8BP8N.rst
M Lib/_pyio.py
M Modules/_io/_iomodule.c
M Modules/_io/_iomodule.h
M Modules/_io/bufferedio.c
diff --git a/Lib/_pyio.py b/Lib/_pyio.py
index adf5d0ecbf6..b59a6509787 100644
--- a/Lib/_pyio.py
+++ b/Lib/_pyio.py
@@ -1182,7 +1182,6 @@ def __init__(self, raw, buffer_size=DEFAULT_BUFFER_SIZE):
self.buffer_size = buffer_size
self._write_buf = bytearray()
self._write_lock = Lock()
- _register_writer(self)
def writable(self):
return self.raw.writable()
@@ -2587,26 +2586,3 @@ def encoding(self):
def detach(self):
# This doesn't make sense on StringIO.
self._unsupported("detach")
-
-
-# ____________________________________________________________
-
-import atexit, weakref
-
-_all_writers = weakref.WeakSet()
-
-def _register_writer(w):
- # keep weak-ref to buffered writer
- _all_writers.add(w)
-
-def _flush_all_writers():
- # Ensure all buffered writers are flushed before proceeding with
- # normal shutdown. Otherwise, if the underlying file objects get
- # finalized before the buffered writer wrapping it then any buffered
- # data will be lost.
- for w in _all_writers:
- try:
- w.flush()
- except:
- pass
-atexit.register(_flush_all_writers)
diff --git a/Misc/NEWS.d/next/Library/2017-12-13-00-00-37.bpo-17852.Q8BP8N.rst b/Misc/NEWS.d/next/Library/2017-12-13-00-00-37.bpo-17852.Q8BP8N.rst
new file mode 100644
index 00000000000..768108d5a54
--- /dev/null
+++ b/Misc/NEWS.d/next/Library/2017-12-13-00-00-37.bpo-17852.Q8BP8N.rst
@@ -0,0 +1 @@
+Revert incorrect fix based on misunderstanding of _Py_PyAtExit() semantics.
diff --git a/Modules/_io/_iomodule.c b/Modules/_io/_iomodule.c
index 5db44f970d2..f0621f4d4ab 100644
--- a/Modules/_io/_iomodule.c
+++ b/Modules/_io/_iomodule.c
@@ -766,8 +766,6 @@ PyInit__io(void)
!(_PyIO_empty_bytes = PyBytes_FromStringAndSize(NULL, 0)))
goto fail;
- _Py_PyAtExit(_PyIO_atexit_flush);
-
state->initialized = 1;
return m;
diff --git a/Modules/_io/_iomodule.h b/Modules/_io/_iomodule.h
index 1dce5dada4e..db8403774ea 100644
--- a/Modules/_io/_iomodule.h
+++ b/Modules/_io/_iomodule.h
@@ -183,5 +183,3 @@ extern PyObject *_PyIO_empty_str;
extern PyObject *_PyIO_empty_bytes;
extern PyTypeObject _PyBytesIOBuffer_Type;
-
-extern void _PyIO_atexit_flush(void);
diff --git a/Modules/_io/bufferedio.c b/Modules/_io/bufferedio.c
index 1ae7a70bbda..d7e82b9dba1 100644
--- a/Modules/_io/bufferedio.c
+++ b/Modules/_io/bufferedio.c
@@ -197,7 +197,7 @@ bufferediobase_write(PyObject *self, PyObject *args)
}
-typedef struct _buffered {
+typedef struct {
PyObject_HEAD
PyObject *raw;
@@ -239,18 +239,8 @@ typedef struct _buffered {
PyObject *dict;
PyObject *weakreflist;
-
- /* a doubly-linked chained list of "buffered" objects that need to
- be flushed when the process exits */
- struct _buffered *next, *prev;
} buffered;
-/* the actual list of buffered objects */
-static buffered buffer_list_end = {
- .next = &buffer_list_end,
- .prev = &buffer_list_end
-};
-
/*
Implementation notes:
@@ -389,21 +379,10 @@ _enter_buffered_busy(buffered *self)
(self->buffer_size * (size / self->buffer_size)))
-static void
-remove_from_linked_list(buffered *self)
-{
- self->next->prev = self->prev;
- self->prev->next = self->next;
- self->prev = NULL;
- self->next = NULL;
-}
-
static void
buffered_dealloc(buffered *self)
{
self->finalizing = 1;
- if (self->next != NULL)
- remove_from_linked_list(self);
if (_PyIOBase_finalize((PyObject *) self) < 0)
return;
_PyObject_GC_UNTRACK(self);
@@ -1827,38 +1806,10 @@ _io_BufferedWriter___init___impl(buffered *self, PyObject *raw,
self->fast_closed_checks = (Py_TYPE(self) == &PyBufferedWriter_Type &&
Py_TYPE(raw) == &PyFileIO_Type);
- if (self->next == NULL) {
- self->prev = &buffer_list_end;
- self->next = buffer_list_end.next;
- buffer_list_end.next->prev = self;
- buffer_list_end.next = self;
- }
-
self->ok = 1;
return 0;
}
-/*
-* Ensure all buffered writers are flushed before proceeding with
-* normal shutdown. Otherwise, if the underlying file objects get
-* finalized before the buffered writer wrapping it then any buffered
-* data will be lost.
-*/
-void _PyIO_atexit_flush(void)
-{
- while (buffer_list_end.next != &buffer_list_end) {
- buffered *buf = buffer_list_end.next;
- remove_from_linked_list(buf);
- if (buf->ok && !buf->finalizing) {
- /* good state and not finalizing */
- Py_INCREF(buf);
- buffered_flush(buf, NULL);
- Py_DECREF(buf);
- PyErr_Clear();
- }
- }
-}
-
static Py_ssize_t
_bufferedwriter_raw_write(buffered *self, char *start, Py_ssize_t len)
{
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