Mailman 3 March 2002 - Python-Dev

mmap patch
by Greg Green March 29, 2002

March 29, 2002

I posted a patch to fix the mmap bus error bug SF #462783. After I posted it I realized I forgot to list my e-mail address. I don't see how to modify sourceforge so that it will use a good e-mail address. Is there a way? -- Greg Green

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March 29, 2002

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Python 2.2 chr representation errors with embedded C
by Mark Szigety March 29, 2002

March 29, 2002

Hello, I have recently made the upgrade to Python 2.2 from 1.5.2. In the Python application which I develop, we have several embedded C functions, one of which is a simple function to convert a hex string to octal--it simply chars each byte and returns the new buffer. However, I have noticed a 0.01% error rate in Python 2.2 which I did not see in Python 1.5.2 (it was 100% accurate). That is, 1 out of 10,000 hex strings will be converted incorrectly in the C function, usually one byte is returned as \x00 instead of what is should be. I also have noticed that in Python 2.2, chr(0xff) returns \xff instead of \377 in Python 1.5.2. Could this be the source of the communication breakdown? I should mention that writing a similar conversion function totally in Python is 100% accurate in Python 2.2 as well as Python 1.5.2, although it is an order of magnitude slower. Any information about the apparent source of this issue would be appreciated! Thanks, Mark

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AIX build problem, 2.2.1c2
by Paul F Dubois March 29, 2002

March 29, 2002

(from LOG.python): ... building 'bsddb' extension ld: 0711-317 ERROR: Undefined symbol: .dbopen ld: 0711-345 Use the -bloadmap or -bnoquiet option to obtain more information. skipping /g/g20/jnjohnso/cdat-3.2/pysrc/build/Python-2.2.1c2/Modules/bsddbmodule. c (build/temp.aix-4.3-2.2/bsddbmodule.o up-to-date) ./Modules/ld_so_aix cc -bI:Modules/python.exp build/temp.aix-4.3-2.2/bsddbmodule.o -L/usr/local/lib -L/g/g20/jnjohnso/arf/lib -ldb -o build/lib.aix-4.3-2.2/bsddb.so WARNING: removing "bsddb" since importing it failed error: build/lib.aix-4.3-2.2/bsddb.so: No such file or directory make: *** [sharedmods] Error 1

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Status of Python Date/Time proposal?
by Kevin Jacobs March 28, 2002

March 28, 2002

Hi all, I've been reading the Python Date/Time design Wiki, and was wondering how all of those issues were shaking out. Specifically, how final is the current prototype, and what are the outstanding issues yet to be resolved? Thanks, -Kevin -- Kevin Jacobs The OPAL Group - Enterprise Systems Architect Voice: (216) 986-0710 x 19 E-mail: jacobs(a)theopalgroup.com Fax: (216) 986-0714 WWW: http://www.theopalgroup.com

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Hi!
by Terry Orgill March 28, 2002

March 28, 2002

I am seriously considering Python, Tkinter and MySQL for an application project. I have it running on linux and Win98. My questions are, does this sound viable for an accounting application? Can I give it a similar look and feel to existing Windows GUI apps?

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Re: Evil Trashcan and GC interaction
by Neil Schemenauer March 28, 2002

March 28, 2002

Guido: > Well, it *also* abuses the ob_refcnt field. My patch fixes that too (by abusing the gc_prev pointer to chain trash together). > How about this wild idea (which Tim & I had simultaneously > yesterday): change the trashcan code to simply leave the > object in the GC generational list, and let the GC code > special-case objects with zero refcnt so that they are > eventually properly disposed? That could probably work. What happens when the GC is disabled? There is insidious bug here. Andrew helped me walk through it and I think we figured it out. First here's the code to trigger it: import gc class Ouch: def __del__(self): for x in range(20): list([]) def f(): gc.set_threshold(5) while 1: t = () # <-- here for i in range(300): t = [t, Ouch()] f() The line marked with "here" is where things go wrong. t used to refer to a long chain of [t, Ouch()]. The SETLOCAL macro in ceval calls Py_XDECREF(GETLOCAL(i)). That starts the deallocation of the list structure. Ouch.__del__ gets called can creates some more objects, triggering a collection. The f frame's traverse gets called and tries to follow the pointer for the t local. It points to memory that was freed by _PyTrash_destroy_chain. Hmm, now that I think about it the GC is not needed to trigger the bug: import gc gc.disable() import sys class Ouch: def __del__(self): print f_frame.f_locals['t'] def f(): global f_frame f_frame = sys._getframe() while 1: t = () for i in range(300): t = [t, Ouch()] f() I haven't figured out the correct solution yet. I'm just giving a status update. :-) Neil

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changing password at SF?
by Skip Montanaro March 28, 2002

March 28, 2002

Didn't see this in the Python-SF-FAQ and SF's docs are pretty mum on the subject... How do I change the password I use when ssh-ing into SF machines? I used the [change password] form from my SF web page, but when I ssh in to the compile farm it still wants my old password. Running the passwd command after logging into a compile farm machine results in "authentication failure" using both my old and new passwords. Is there perhaps some other machine I should login to? (For those of you not involved with the python.org website, this has immediate practical implications, because it appears one of the python.org machines was broken into.) Thx, Skip

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Discussion on the Python RPMs...
by Sean Reifschneider March 28, 2002

March 28, 2002

Guido and I have, for a while, been having some discussions about the Python RPMs. He suggested that I bring the topic up here for further discussion. One of the biggest things that we've discussed is that of the naming of the resultant Python. With the 2.1 releases, I started installing the latest stable Python as /usr/bin/python2, so as not to conflict with the Red Hat 1.5.2 version installed in /usr/bin/python (which many of the system tools require). For test releases, I've been using the full release name as the extension, /usr/bin/python2.2c1 (or was it just python2.2?). This is so that multiple versions can be installed 1.5.2, 2.1, 2.2c1... I know there are some other things brought up, but I can't remember them off hand. If it weren't for hackingsociety.org, I probably wouldn't have *ANY* time to work on community projects this month... So, first of all, comments on the current naming scheme? Note that the binary extension can be easily changed by modifying one line in the .spec file and building again. Handy for users who just want to forget about 1.5.2 and don't mind that some of the RedHat tools may break. Also, any other comments on the RPMs? Thanks, Sean -- Canadian phone sex: What kind of hockey jersey are you wearing? Sean Reifschneider, Inimitably Superfluous <jafo(a)tummy.com> tummy.com - Linux Consulting since 1995. Qmail, KRUD, Firewalls, Python

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repr(x) != x.__repr__()
by Oren Tirosh March 28, 2002

March 28, 2002

This phenomenon is not really specific to repr(). It occurs with new-style classes when methods are assigned. Example: class A(object): def __repr__(self): return 'abc' >>>a = A() >>>a.__repr__ = lambda: 'abc' >>>repr(a) 'abc' >>>a.__repr__() '123' Whenever the method is accessed by Python code it sees the assigned method in the object's __dict__. Builtins like repr(), iter() etc, see the original class method. With classic objects both Python and C code see the assigned function. This is bug #515336 on sourceforge. Is anyone aware of any other cases where C code and Python code don't see objects the same way? Oren

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