[issue12513] codec.StreamReaderWriter: issues with interlaced read-write
STINNER Victor
report at bugs.python.org
Thu Jul 7 15:12:47 CEST 2011
New submission from STINNER Victor <victor.stinner at haypocalc.com>:
The following test fails with an AssertionError('a' != 'b') on the first read.
import codecs
FILENAME = 'test'
with open(FILENAME, 'wb') as f:
f.write('abcd'.encode('utf-8'))
with codecs.open(FILENAME, 'r+', encoding='utf-8') as f:
f.write("1")
pos = f.writer.tell()
assert pos == 1, "writer pos: %s != 1" % pos
pos = f.reader.tell()
assert pos == 1, "reader pos: %s != 1" % pos
pos = f.stream.tell()
assert pos == 1, "stream pos: %s != 1" % pos
# read() must call writer.flush()
char = f.read(1)
assert char == 'b', "%r != 'b'" % (char,)
# write() must rewind the raw stream
f.write('3')
tail = f.read()
assert tail == 'd', "%r != 'd'" % (tail,)
f.flush()
with open(FILENAME, 'rb') as f:
assert f.read() == b'1b3d'
I suppose that readline(), readlines() and __next__() have also issues.
See also issue #12215: similar issue with io.TextIOWrapper.
----------
components: Library (Lib), Unicode
messages: 139975
nosy: haypo
priority: normal
severity: normal
status: open
title: codec.StreamReaderWriter: issues with interlaced read-write
versions: Python 2.7, Python 3.2, Python 3.3
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Python tracker <report at bugs.python.org>
<http://bugs.python.org/issue12513>
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