[Python-checkins] cpython (2.7): Issue #12062: In the `io` module, fix a flushing bug when doing a certain
antoine.pitrou
python-checkins at python.org
Fri May 13 00:32:29 CEST 2011
http://hg.python.org/cpython/rev/0d24d4c537a6
changeset: 70060:0d24d4c537a6
branch: 2.7
parent: 70051:534a9e274d88
user: Antoine Pitrou <solipsis at pitrou.net>
date: Fri May 13 00:31:52 2011 +0200
summary:
Issue #12062: In the `io` module, fix a flushing bug when doing a certain
type of I/O sequence on a file opened in read+write mode (namely: reading,
seeking a bit forward, writing, then seeking before the previous write but
still within buffered data, and writing again).
files:
Lib/test/test_io.py | 26 ++++++++++++++++++++++++++
Misc/NEWS | 5 +++++
Modules/_io/bufferedio.c | 2 +-
3 files changed, 32 insertions(+), 1 deletions(-)
diff --git a/Lib/test/test_io.py b/Lib/test/test_io.py
--- a/Lib/test/test_io.py
+++ b/Lib/test/test_io.py
@@ -1462,6 +1462,32 @@
self.assertEqual(s,
b"A" + b"B" * overwrite_size + b"A" * (9 - overwrite_size))
+ def test_write_rewind_write(self):
+ # Various combinations of reading / writing / seeking backwards / writing again
+ def mutate(bufio, pos1, pos2):
+ assert pos2 >= pos1
+ # Fill the buffer
+ bufio.seek(pos1)
+ bufio.read(pos2 - pos1)
+ bufio.write(b'\x02')
+ # This writes earlier than the previous write, but still inside
+ # the buffer.
+ bufio.seek(pos1)
+ bufio.write(b'\x01')
+
+ b = b"\x80\x81\x82\x83\x84"
+ for i in range(0, len(b)):
+ for j in range(i, len(b)):
+ raw = self.BytesIO(b)
+ bufio = self.tp(raw, 100)
+ mutate(bufio, i, j)
+ bufio.flush()
+ expected = bytearray(b)
+ expected[j] = 2
+ expected[i] = 1
+ self.assertEqual(raw.getvalue(), expected,
+ "failed result for i=%d, j=%d" % (i, j))
+
def test_truncate_after_read_or_write(self):
raw = self.BytesIO(b"A" * 10)
bufio = self.tp(raw, 100)
diff --git a/Misc/NEWS b/Misc/NEWS
--- a/Misc/NEWS
+++ b/Misc/NEWS
@@ -80,6 +80,11 @@
Library
-------
+- Issue #12062: In the `io` module, fix a flushing bug when doing a certain
+ type of I/O sequence on a file opened in read+write mode (namely: reading,
+ seeking a bit forward, writing, then seeking before the previous write but
+ still within buffered data, and writing again).
+
- Issue #8498: In socket.accept(), allow to specify 0 as a backlog value in
order to accept exactly one connection. Patch by Daniel Evers.
diff --git a/Modules/_io/bufferedio.c b/Modules/_io/bufferedio.c
--- a/Modules/_io/bufferedio.c
+++ b/Modules/_io/bufferedio.c
@@ -1810,7 +1810,7 @@
avail = Py_SAFE_DOWNCAST(self->buffer_size - self->pos, Py_off_t, Py_ssize_t);
if (buf.len <= avail) {
memcpy(self->buffer + self->pos, buf.buf, buf.len);
- if (!VALID_WRITE_BUFFER(self)) {
+ if (!VALID_WRITE_BUFFER(self) || self->write_pos > self->pos) {
self->write_pos = self->pos;
}
ADJUST_POSITION(self, self->pos + buf.len);
--
Repository URL: http://hg.python.org/cpython
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