[PyQt] SEGV in QTextStream.atEnd on Mac OS

[David Cortesi]

The following code will reliably produce a crash on my Mac OS 10.6.8 (snow
leopard) system. Python 2.6.1.

from __future__ import division
from __future__ import print_function
from __future__ import unicode_literals
from future_builtins import *

from PyQt4.QtCore import (QFile, QTextStream, QString)

ts = QTextStream(QString(u"hello\n sailor\n"),QFile.ReadOnly)
print(ts.atEnd())
qs = ts.readAll()
print(u'a. {0}:{1}'.format(qs.length(),qs))
print(ts.atEnd())
ts = QTextStream(QString(u"hello\n sailor\n"),QFile.ReadOnly)
print(ts.atEnd())

The printed output preceding the crash is usually,
False
a. 0:
True
But sometimes the displayed data is longer and contains garbage characters.

The crash report starts,
Exception Type:  EXC_BAD_ACCESS (SIGSEGV)
Exception Codes: KERN_INVALID_ADDRESS at 0x0000000000000011
Crashed Thread:  0  Dispatch queue: com.apple.main-thread

Thread 0 Crashed:  Dispatch queue: com.apple.main-thread
0   QtCore                            0x000000010149d744
QTextStream::atEnd() const + 20
1   QtCore.so                         0x000000010113d194
meth_QTextStream_atEnd + 100
2   org.python.python                 0x0000000100089187 PyEval_EvalFrameEx
+ 15317
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