Mailman 3 September 2008 - Python-Dev

Python performance through times
by Antoine Pitrou Sept. 5, 2008

Sept. 5, 2008

Here's an interesting blog post comparing Python performance of various versions from 2.2.3 upto the latest 3.0 beta. http://www.ogre.com/node/147 The fact that only Mandelbrot calculation (a hardly representative benchmark for a high-level dynamic language such as Python) has become significantly slower is rather a good sign IMO. cheers Antoine.

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Bug in SimpleHTTPRequestHandler.send_head?
by Kim Gräsman Sept. 5, 2008

Sept. 5, 2008

Hi all, I'm new to this group and the Python language as such. I stumbled on it when I joined a project to build a rich network library for C++, which in turn uses Python and its CGI HTTP server implementation as part of its unit test suite. We're having a little trouble when serving a text file containing Windows line endings (CRLF) -- the resulting content contains Unix line endings only (LF). This breaks our tests, because we can't verify that the body, as parsed by our HTTP client, is the … [View More]same as the source file we're serving through the Python HTTP server. I've isolated it to the SimpleHTTPRequestHandler.send_head method in SimpleHTTPServer.py: -- ctype = self.guess_type(path) if ctype.startswith('text/'): mode = 'r' else: mode = 'rb' try: f = open(path, mode) except IOError: self.send_error(404, "File not found") return None -- The f object is returned from this method, and used with shutil.copyfileobj to copy the contents to the output stream. This is easily fixed by omitting the content-type check entirely, and blindly using mode 'rb', and I think that makes sense, because the server should not be concerned with the contents of the body, so treating it as a binary stream seems right. This also fixes another issue, where the actual body size differs from what's specified in the Content-Length header, because CR characters are stripped when the body is served, but Content-Length contains the source file's binary size. I'm not sure which source control system you're using, so I won't try to provide a patch, but I believe the code should read: -- if os.path.isdir(path): if not self.path.endswith('/'): # redirect browser - doing basically what apache does self.send_response(301) self.send_header("Location", self.path + "/") self.end_headers() return None for index in "index.html", "index.htm": index = os.path.join(path, index) if os.path.exists(index): path = index break else: return self.list_directory(path) #patch: removed content-type check try: f = open(path, 'rb') #patch: always open in binary mode except IOError: self.send_error(404, "File not found") return None self.send_response(200) self.send_header("Content-type", self.guess_type(path)) #patch: content-type check here instead fs = os.fstat(f.fileno()) -- My changes marked with "#patch[...]". Grateful for any comments! Best wishes, - Kim [View Less]

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Can/should built-in functions get __get__?
by Terry Reedy Sept. 5, 2008

Sept. 5, 2008

One of the nice features of 3.0 is that differences between classes defined in C and Python (other than speed) are mostly erased or hidden from the view of a Python programmer. However, there are still sometimes surprising and quite visible differences between 'functions' written in C and Python. Can these be better unified also? In particular, built-in functions, in spite of of being labeled 'builtin_function_or_method', are not usable as methods because they lack the __get__ method … [View More]

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Re: [Python-Dev] 'warnings' module changes still breaking Twisted, still looking for a fix
by glyph＠divmod.com Sept. 4, 2008

Sept. 4, 2008

On 10:18 pm, musiccomposition(a)gmail.com wrote: >That's why catch_warning keeps track of the warnings filter too, so >you can call warnings.simplefilter("always") within the context >manager and the filter state will be restored. Thanks for the pointer - this is interesting. I misunderstood the way the warnings filter worked. It looks like this combination of features may in fact be all we need. It would be nice if application code could otherwise "officially" keep track of the … [View More]

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'warnings' module changes still breaking Twisted, still looking for a fix
by glyph＠divmod.com Sept. 4, 2008

Sept. 4, 2008

With the 2.6 final release impending, the Twisted community buildbot is still red, <http://bit.ly/zFymN>, but there only seems to be one real issue: the warn_explicit change. This seems like it could be a pretty minor bit of maintenance to clear up on our end, if Python provided the appropriate hook. The current solution we have in mind for this problem is to build our own warnings module <http://bit.ly/4F3Qr2>, but that is obviously inelegant. While we do want to … [View More]

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patch for Cookie.py to add support for HttpOnly
by Matt Chisholm Sept. 4, 2008

Sept. 4, 2008

Eighteen months ago, Arvin Schnell contributed a really straightforward three-line patch to Cookie.py adding support for the HttpOnly flag on cookies: http://bugs.python.org/issue1638033 In the last eighteen months, HttpOnly has become a de-facto extension to the cookie standard. It is now supported by IE 7, Firefox 3, and Opera 9.5 (and there's a bug open against WebKit to support it): http://www.owasp.org/index.php/HTTPOnly Ruby, Perl, and PHP all support creating HttpOnly cookies now … [View More]

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3rd-party dbms
by Oleg Broytmann Sept. 4, 2008

Sept. 4, 2008

Brett Cannon <brett(a)python.org> wrote: > for 3.1 there is nothing saying we can't change shelve and the > dbm package to allow 3rd-party code to register with the dbm package > such that bsddb can be used as needed behind the scenes. Many years ago I wrote toy hashes based on ZODB and MetaKit. Registering them with anydbm was easy: import anydbm anydbm._names.insert(len(anydbm._names)-1, ['ZODBhash', 'MKhash']) # Insert before dumbdbm More complex part was … [View More]

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Re: [Python-Dev] Durus memory
by Binger David Sept. 4, 2008

Sept. 4, 2008

I'm sorry this post is a bit off-topic, but I think I should correct this. On Sep 4, 2008, at 11:54 AM, Oleg wrote: > Durus (and ZODB) has an index of all objects, the index is stored in > memory AFAIK - a real problem if one has millions of objects. Durus now has an option to store the index in the data file in a form that is usable directly from disk. With this option, the in-memory index is only for objects changed since the last pack. Durus works fine with millions of objects, … [View More]

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Re: [Python-Dev] C API for gc.enable() and gc.disable()
by Andrey Zhmoginov Sept. 4, 2008

Sept. 4, 2008

> > Would anyone mind if I did add a public C API for gc.disable() and > gc.enable()? I would like to use it as an optimization for the pickle > module (I found out that I get a good 2x speedup just by disabling the > GC while loading large pickles). Of course, I could simply import the > gc module and call the functions there, but that seems overkill to me. > I included the patch below for review. > I don't know if the following question is relevant, but it seems … [View More]that many people here are familiar with Python cyclic garbage collector. I see Python [v2.5.2 (r252:60911, Jul 31 2008, 17:28:52)] crashing with Segment fault when I extend Python with a very simple module. This behavior is observed when I create a thousand of lists (it does not crash with 10-100) in the module with the garbage collector turned on. When I turn it off - everything is perfect. I suspect that it is my module, but if it is a Python bug ( _GC_Malloc? memory leak somewhere?), it may be worth reporting. The gdb "where" reply is the following: #0 0x080d8de9 in PyErr_Occurred () #1 0x080f508f in _PyObject_GC_Malloc () #2 0x080f5155 in _PyObject_GC_New () #3 0x08079c98 in PyList_New () #4 0xb7f53519 in draw_d_simple () from ./rt/rt_core.so #5 0xb7cf7833 in ffi_call_SYSV () from /usr/lib/python2.5/lib-dynload/_ctypes.so #6 0xb7cf766a in ffi_call () from /usr/lib/python2.5/lib-dynload/_ctypes.so #7 0xb7cf2534 in _CallProc () from /usr/lib/python2.5/lib-dynload/_ctypes.so #8 0xb7cec02a in ?? () from /usr/lib/python2.5/lib-dynload/_ctypes.so #9 0x0805cb97 in PyObject_Call () #10 0x080c7aa7 in PyEval_EvalFrameEx () #11 0x080c96e5 in PyEval_EvalFrameEx () #12 0x080cb1f7 in PyEval_EvalCodeEx () #13 0x080cb347 in PyEval_EvalCode () #14 0x080ea818 in PyRun_FileExFlags () #15 0x080eaab9 in PyRun_SimpleFileExFlags () #16 0x08059335 in Py_Main () #17 0x080587f2 in main () The crashing python code is: from ctypes import * import gc core = CDLL( "./tst.so" ) core.a.argtypes = [] core.a.restype = py_object #gc.disable() core.a() #gc.enable() And tst.cpp is: #include <Python.h> extern "C" { PyObject *a(); } PyObject *a() { int n = 1000; PyObject *item; for ( int i = 0; i < n; i++ ) item = PyList_New( 0 ); // Crashes here (somewhere in between). return item; } tst.cpp is compiled with: g++ -shared -Wl,-soname,tst.tmp.so -o tst.so tst.o g++ -I /usr/include/python2.5 -Wall -fPIC -o tst.o -c tst.cpp Thanks for your help! - Andrew. [View Less]

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Python 3.0b3 documentation typo
by Reed O'Brien Sept. 4, 2008

Sept. 4, 2008

I was reading through the Dictionary views section: http://docs.python.org/dev/3.0/library/stdtypes.html#dictionary-view-objects Unless I am mistaken; the intersection at the end of the example usage should be: >>> keys & {'eggs', 'bacon', 'salad'} {'bacon'} Cheers, ~ro

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