Martin v. Löwis writes:
> Due to some
> unfortunate historical reasons, there is code which enters free()
> without holding the GIL - and that is what the allocator specifically
> deals with. Except for this single case, all callers of the allocator
> are required to hold the GIL.
Donovan Baarda writes:
> Just curious; is that "one case" a bug that needs fixing, or is the some
> reason this case can't be changed to use the GIL? Surely making it
> mandatory for all free() calls to hold the GIL is easier than making the
> allocator deal with the one case where this isn't done.
What Martin is trying to say here is that it _IS_ mandatory to hold
the GIL when calling free(). However, there is some very old code in
existance (written by other people) which calls free() without holding
the GIL. We work very hard to provide backward compatibility, so we
are jumping through hoops to ensure that even this old code which is
violating the rules doesn't get broken.
-- Michael Chermside
Last August, James Knight posted to python-dev, "There's a fair number
of classes that claim they are defined in __builtin__, but do not
actually appear there". There was a discussion and James submitted
this patch:
http://sourceforge.net/tracker/index.php?func=detail&aid=1009811&group_id=5…
The final result of the discussion is unclear. Guido declared himself
+0.5 on the concept, but nobody has reviewed the patch in detail yet.
The original email thread starts here:
http://mail.python.org/pipermail/python-dev/2004-August/047477.html
The patch still applies, and test cases still run OK afterwards.
Now that 2.4 has been released it is perhaps a good time to discuss in
on python-dev again. If it isn't discussed, then the patch should be
closed due to lack of interest.
Alan.
--
Alan Green
alan.green(a)cardboard.nu - http://cardboard.nu
In my blog I wrote:
Let's get rid of unbound methods. When class C defines a method f, C.f
should just return the function object, not an unbound method that
behaves almost, but not quite, the same as that function object. The
extra type checking on the first argument that unbound methods are
supposed to provide is not useful in practice (I can't remember that
it ever caught a bug in my code) and sometimes you have to work around
it; it complicates function attribute access; and the overloading of
unbound and bound methods on the same object type is confusing. Also,
the type checking offered is wrong, because it checks for subclassing
rather than for duck typing.
This is a really simple change to begin with:
*** funcobject.c 28 Oct 2004 16:32:00 -0000 2.67
--- funcobject.c 4 Jan 2005 18:23:42 -0000
***************
*** 564,571 ****
static PyObject *
func_descr_get(PyObject *func, PyObject *obj, PyObject *type)
{
! if (obj == Py_None)
! obj = NULL;
return PyMethod_New(func, obj, type);
}
--- 564,573 ----
static PyObject *
func_descr_get(PyObject *func, PyObject *obj, PyObject *type)
{
! if (obj == NULL || obj == Py_None) {
! Py_INCREF(func);
! return func;
! }
return PyMethod_New(func, obj, type);
}
There are some test suite failures but I suspect they all have to do
with checking this behavior.
Of course, more changes would be needed: docs, the test suite, and
some simplifications to the instance method object implementation in
classobject.c.
Does anyone think this is a bad idea? Anyone want to run with it?
--
--Guido van Rossum (home page: http://www.python.org/~guido/)
https://sourceforge.net/tracker/index.php?func=detail&aid=1103689&group_id=…
Here's a patch that gets rid of unbound methods, as
discussed here before. A function's __get__ method
now returns the function unchanged when called without
an instance, instead of returning an unbound method object.
I couldn't remove support for unbound methods
completely, since they were used by the built-in
exceptions. (We can get rid of that use once we convert
to new-style exceptions.)
For backward compatibility, functions now have
read-only im_self and im_func attributes; im_self is
always None, im_func is always the function itself.
(These should issue warnings, but I haven't added that
yet.)
The test suite passes. (I have only tried "make test"
on a Linux box.)
What do people think? (My main motivation for this, as stated before,
is that it adds complexity without much benefit.)
--
--Guido van Rossum (home page: http://www.python.org/~guido/)
Aahz, writing as pycon(a)python.org, wrote:
> It's still January 28 here -- register now! I don't know if we'll be
> able to extend the registration price beyond that.
Just in case anybody else might be wondering when the early bird
registration deadline is, I've asked the registration team to allow the
early bird price as long as it's January 28th somewhere in the world.
There have been rumors that Guido will not be attending PyCon this year.
I am happy to scotch them by pointing out that Guido van Rossum's
keynote address will be on its traditional Thursday morning. I look
forward to joining you all to hear Guido speak on "The State of Python".
regards
Steve
--
Steve Holden http://www.holdenweb.com/
Python Web Programming http://pydish.holdenweb.com/
Holden Web LLC +1 703 861 4237 +1 800 494 3119
I see a need for this patch - I've had to write
"datetime(*(time.strptime(date_string, format)[0:6]))" far too many
times.
I don't understand the C API well enough to check if
reference counts are handled properly, but otherwise the
implementation looks straight forward.
Documentation looks good and the test passes on my machine.
Two suggestions:
1. In the time module, the strptime() function's format
parameter is optional. For consistency's sake, I'd expect
datetime.strptime()'s format parameter also to be optional.
(On the other hand, the default value for the format is not
very useful.)
2. Since strftime is supported by datetime.time,
datetime.date and datetime.datetime, I'd also expect
strptime to be supported by all three classes. Could you add
that now, or would it be better to do it as a separate patch?
Alan.
--
Alan Green
alan.green(a)cardboard.nu - http://cardboard.nu
G'day,
I've Cc'ed this to zope-coders as it might affect other Zope developers
and it had me stumped for ages. I couldn't find anything on it anywhere,
so I figured it would be good to get something into google :-).
We are developing a Zope2.7 application on Debian GNU/Linux that is
using fop to generate pdf's from xml-fo data. fop is a java thing, and
we are using popen2.Popen3(), non-blocking mode, and select loop to
write/read stdin/stdout/stderr. This was all working fine.
Then over the Christmas chaos, various things on my development system
were apt-get updated, and I noticed that java/fop had started
segfaulting. I tried running fop with the exact same input data from the
command line; it worked. I wrote a python script that invoked fop in
exactly the same way as we were invoking it inside zope; it worked. It
only segfaulted when invoked inside Zope.
I googled and tried everything... switched from j2re1.4 to kaffe, rolled
back to a previous version of python, re-built Zope, upgraded Zope from
2.7.2 to 2.7.4, nothing helped. Then I went back from a linux 2.6.8
kernel to a 2.4.27 kernel; it worked!
After googling around, I found references to recent attempts to resolve
some signal handling problems in Python threads. There was one post that
mentioned subtle differences between how Linux 2.4 and Linux 2.6 did
signals to threads.
So it seems this is a problem with Python threads and Linux kernel 2.6.
The attached program demonstrates that it has nothing to do with Zope.
Using it to run "fop-test /usr/bin/fop </dev/null" on a Debian box with
fop installed will show the segfault. Running the same thing on a
machine with 2.4 kernel will instead get the fop "usage" message. It is
not a generic fop/java problem with 2.6 because the commented
un-threaded line works fine. It doesn't seem to segfault for any
command... "cat -" works OK, so it must be something about java
contributing.
After searching the Python bugs, the closest I could find was #971213
<http://sourceforge.net/tracker/?group_id=5470&atid=105470&func=detail&aid=9…>. Is this the same bug? Should I submit a new bug report? Is there any other way I can help resolve this?
BTW, built in file objects really could use better non-blocking
support... I've got a half-drafted PEP for it... anyone interested in
it?
--
Donovan Baarda <abo(a)minkirri.apana.org.au>
http://minkirri.apana.org.au/~abo/
I just submitted a bug report for setup.py:
http://python.org/sf/1109602
It begins:
Python's setup.py has grown way out of control. I'm trying to build and
install Python 2.4.0 on a Solaris system with Tcl/Tk installed in a
non-standard place and I can't figure out the incantation to tell
setup.py to look where they are installed.
...
and ends:
This might be an excellent sprint topic for PyCon.
Skip
I just wrote a new C API function (PyItem_GetItem) that supports slicing for
arbitrary iterators. A patch for current CVS is at http://www.python.org/sf/1108272
For simple indices it does the iteration manually, and for extended slices it
returns an itertools.islice object.
As a trivial example, here's how to skip the head of a zero-numbered list:
for i, item in enumerate("ABCDEF")[1:]:
print i, item
Is this idea a non-starter, or should I spend my holiday on Wednesday finishing
it off and writing the documentation and tests for it?
Regards,
Nick.
--
Nick Coghlan | ncoghlan(a)email.com | Brisbane, Australia
---------------------------------------------------------------
http://boredomandlaziness.skystorm.net
