New submission from Raymond Hettinger <raymond.hettin...@gmail.com>:
A dialog on python-dev suggests that dict.setdefault() was intended to be atomic and that a number of experienced developers have deployed code relying on its atomicity: http://mail.python.org/pipermail/python-3000/2007-July/008693.html The actual implementation shows a second call to PyDict_Setitem() which can call PyObject_Hash() which can call arbitrary Python code. http://hg.python.org/cpython/file/2.7/Objects/dictobject.c#l1937 This fix is straight-forward, use the results of the initial lookup to insert the default object. This will make the operation atomic and it will make it faster. ---------- components: Interpreter Core messages: 148782 nosy: rhettinger priority: normal severity: normal status: open title: Make dict.setdefault() atomic type: behavior versions: Python 2.7, Python 3.1, Python 3.2, Python 3.3 _______________________________________ Python tracker <rep...@bugs.python.org> <http://bugs.python.org/issue13521> _______________________________________ _______________________________________________ Python-bugs-list mailing list Unsubscribe: http://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com
