[Python-Dev] Re: Inadequate error reporting during function call setup stage
On 21/02/2021 23:06, Terry Reedy wrote: On 2/21/2021 12:04 PM, Paul Sokolovsky wrote: Traceback (most recent call last): File "pseudoc_tool.py", line 91, in first_class_function_value(func, **pass_params) TypeError: print() got an unexpected keyword argument 'noann' This is not typical behavior in current Python (3.8+). The way I understand it's not about print(), it's about disambiguating multiple functions with the same name. Example: PS > type .\ambiguous_names.py import random def do_stuff(): pass f = do_stuff def do_stuff(a, b): pass g = do_stuff random.choice([f, g])(42) PS > py .\ambiguous_names.py Traceback (most recent call last): File "...\ambiguous_names.py", line 13, in random.choice([f, g])(42) TypeError: do_stuff() missing 1 required positional argument: 'b' The traceback gives no clue which of the two do_stuff() functions caused the error, you have to check both implementations. If that is a comman problem one might consider including module name and co_firstlineno in the message, or at least adding the relevant do_stuff() function to the exception's args. ___ Python-Dev mailing list -- python-dev@python.org To unsubscribe send an email to python-dev-le...@python.org https://mail.python.org/mailman3/lists/python-dev.python.org/ Message archived at https://mail.python.org/archives/list/python-dev@python.org/message/E7OUHLWXP3NHEM3UZOBWP5AQRSFL5RDO/ Code of Conduct: http://python.org/psf/codeofconduct/
Re: [Python-Dev] python2.7 infinite recursion when loading pickled object
Terry Reedy wrote: On 8/11/2014 5:10 AM, Schmitt Uwe (ID SIS) wrote: Python usage questions should be directed to python-list, for instance. I discovered a problem using cPickle.loads from CPython 2.7.6. The problem is your code having infinite recursion. You only discovered it with pickle. The last line in the following code raises an infinite recursion class T(object): def __init__(self): self.item = list() def __getattr__(self, name): return getattr(self.item, name) This is a (common) bug in your program. __getattr__ should call self.__dict__(name) to avoid the recursion. Read again. The OP tries to delegate attribute lookup to an (existing) attribute. IMO the root cause of the problem is that pickle looks up __dunder__ methods in the instance rather than the class. ___ Python-Dev mailing list Python-Dev@python.org https://mail.python.org/mailman/listinfo/python-dev Unsubscribe: https://mail.python.org/mailman/options/python-dev/archive%40mail-archive.com
Re: [Python-Dev] python2.7 infinite recursion when loading pickled object
Chris Angelico wrote: On Mon, Aug 11, 2014 at 9:40 PM, Peter Otten __pete...@web.de wrote: Read again. The OP tries to delegate attribute lookup to an (existing) attribute. IMO the root cause of the problem is that pickle looks up __dunder__ methods in the instance rather than the class. The recursion comes from the attempted lookup of self.item, when __init__ hasn't been called. You are right. Sorry for the confusion. ___ Python-Dev mailing list Python-Dev@python.org https://mail.python.org/mailman/listinfo/python-dev Unsubscribe: https://mail.python.org/mailman/options/python-dev/archive%40mail-archive.com
[Python-Dev] Function to handle None in sort operation, was Re: python 3 niggle: None 1 raises TypeError
M.-A. Lemburg wrote: IMO, it was a mistake to have None return a TypeError in comparisons, since it makes many typical data operations fail, e.g. Python2: l = [1,2,None,4,5,None,6] l.sort() l [None, None, 1, 2, 4, 5, 6] Python3: l = [1,2,None,4,5,None,6] l.sort() Traceback (most recent call last): File stdin, line 1, in module TypeError: unorderable types: NoneType() int() While it is trivial to fix sorted([1,2,None,4,5,None,6], ... key=lambda x: (x is None, x)) [1, 2, 4, 5, 6, None, None] maybe the key should be given a name like functools.none_first/none_last in order to offer a standard approach? On the other hand I'm not sure I like none_last(x) none_last(y) ___ Python-Dev mailing list Python-Dev@python.org https://mail.python.org/mailman/listinfo/python-dev Unsubscribe: https://mail.python.org/mailman/options/python-dev/archive%40mail-archive.com
Re: [Python-Dev] type.__subclasses__() doesn't work
Steven D'Aprano wrote: On Wed, Oct 09, 2013 at 12:20:18PM +0200, Antoine Pitrou wrote: Hello, Just noticed the following quirk: type.__subclasses__() Traceback (most recent call last): File stdin, line 1, in module TypeError: descriptor '__subclasses__' of 'type' object needs an argument Yet it would be nice to know about the subclasses of type. py type.__subclasses__(type) [class 'abc.ABCMeta', class 'string._TemplateMetaclass'] The underlying problem seems to be that there is no helper function to bypass the instance attribute. Compare: class T(type): ... def __len__(self): return 0 ... class A(metaclass=T): ... def __len__(self): return 1 ... A.__len__() Traceback (most recent call last): File stdin, line 1, in module TypeError: __len__() missing 1 required positional argument: 'self' len(A) 0 So should there be a subclasses() function, in the operator module perhaps? ___ Python-Dev mailing list Python-Dev@python.org https://mail.python.org/mailman/listinfo/python-dev Unsubscribe: https://mail.python.org/mailman/options/python-dev/archive%40mail-archive.com
Re: [Python-Dev] experimental: Misc/NEWS included in docs
Georg Brandl wrote: at http://docs.python.org/3.3/whatsnew/news.html, there is now a rendering of Misc/NEWS with tracker links and a crude filtering capability. I thought that this will complement the whatsnew documents nicely for people looking for more detail. Please let me know if it's useful, or what could be done to make it *more* useful. Maybe you could supress those sections that become empty when a filter is applied. ___ Python-Dev mailing list Python-Dev@python.org http://mail.python.org/mailman/listinfo/python-dev Unsubscribe: http://mail.python.org/mailman/options/python-dev/archive%40mail-archive.com
Re: [Python-Dev] Should urlencode() sort the query parameters (if they come from a dict)?
Guido van Rossum wrote:
I wonder if it wouldn't make sense to change urlencode() to generate
URLs that don't depend on the hash order, for all versions of Python
that support PYTHONHASHSEED? It seems a one-line fix:
query = query.items()
with this:
query = sorted(query.items())
This would not prevent breakage of unit tests, but it would make a
much simpler fix possible: simply sort the parameters in the URL.
Thoughts?
There may be people who mix bytes and str or pass other non-str keys:
query = {ba:bb, c:d, 5:6}
urlencode(query)
'a=bc=d5=6'
sorted(query.items())
Traceback (most recent call last):
File stdin, line 1, in module
TypeError: unorderable types: str() bytes()
Not pretty, but a bugfix should not break such constructs.
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Re: [Python-Dev] Checking if unsigned int less then zero.
Dmitriy Tochansky wrote:
Playing with cpython source, I found some strange strings in
socketmodule.c:
---
if (flowinfo 0 || flowinfo 0xf) {
PyErr_SetString(
PyExc_OverflowError,
getsockaddrarg: flowinfo must be 0-1048575.);
return 0;
}
---
---
if (flowinfo 0 || flowinfo 0xf) {
PyErr_SetString(PyExc_OverflowError,
getsockaddrarg: flowinfo must be 0-1048575.);
return NULL;
}
---
The flowinfo variable declared few strings above as unsgined int. Is
there any practical sense in this check? Seems like gcc just removes
this check. I think any compiler will generate code that checks as
unsigned, for example in x86 its JAE/JGE. May be this code is for bad
compilers or exotic arch?
I think you are right, the 0 check is redundant. The developers probably
forgot to remove it when
http://bugs.python.org/issue9975
was fixed.
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Re: [Python-Dev] Playing with a new theme for the docs, iteration 2
Georg Brandl wrote: Here's another try, mainly with default browser font size, more contrast and collapsible sidebar again: http://www.python.org/~gbrandl/build/html2/ Nice! Lightweight and readable. From the bikeshedding department: * Inlined code doesn't need the gray background. The bold font makes it stand out enough. * Instead of the box consider italics or another color for [New in ...] text. * Nobody is going to switch off the prompts for interactive sessions. * Maybe the Next/Previous Page headers on the left could link to the respective page. * Short descriptions in the module index don't need italics. * The disambiguation in the index table could use a different style instead of the parentheses. ___ Python-Dev mailing list Python-Dev@python.org http://mail.python.org/mailman/listinfo/python-dev Unsubscribe: http://mail.python.org/mailman/options/python-dev/archive%40mail-archive.com
Re: [Python-Dev] Playing with a new theme for the docs, iteration 2
Serhiy Storchaka wrote: * Maybe the Next/Previous Page headers on the left could link to the respective page. Do you mean next/previous links in header/footer? No, I mean the two sections in the sidebar on the left, below Table of Contents. ___ Python-Dev mailing list Python-Dev@python.org http://mail.python.org/mailman/listinfo/python-dev Unsubscribe: http://mail.python.org/mailman/options/python-dev/archive%40mail-archive.com
Re: [Python-Dev] Python3 regret about deleting list.sort(cmp=...)
Guido van Rossum wrote: I was just reminded that in Python 3, list.sort() and sorted() no longer support the cmp (comparator) function argument. The reason is that the key function argument is always better. But now I have a nagging doubt about this: I recently advised a Googler who was sorting a large dataset and running out of memory. My analysis of the situation was that he was sorting a huge list of short lines of the form shortstring,integer with a key function that returned a tuple of the form (shortstring, integer). Using the key function argument, in addition to N short string objects, this creates N tuples of length 2, N more slightly shorter string objects, and N integer objects. (Not to count a parallel array of N more pointers.) Given the object overhead, this dramatically increased the memory usage. It so happens that in this particular Googler's situation, memory is constrained but CPU time is not, and it would be better to parse the strings over and over again in a comparator function. But in Python 3 this solution is no longer available. How bad is that? I'm not sure. But I'd like to at least get the issue out in the open. While there are other arguments to reintroduce cmp (or less_than instead?) the memory problem could also be addressed with a dont_cache_keys flag or max_cache_keys limit. Peter ___ Python-Dev mailing list Python-Dev@python.org http://mail.python.org/mailman/listinfo/python-dev Unsubscribe: http://mail.python.org/mailman/options/python-dev/archive%40mail-archive.com
Re: [Python-Dev] Rethinking intern() and its data structure
John Arbash Meinel wrote: Not as big of a difference as I thought it would be... But I bet if there was a way to put the random shuffle in the inner loop, so you weren't accessing the same identical 25k keys internally, you might get more interesting results. You can prepare a few random samples during startup: $ python -m timeit -sfrom random import sample; d = dict.fromkeys(xrange(10**7)); nextrange = iter([sample(xrange(10**7),25000) for i in range(200)]).next for x in nextrange(): d.get(x) 10 loops, best of 3: 20.2 msec per loop To put it into perspective: $ python -m timeit -sd = dict.fromkeys(xrange(10**7)); nextrange = iter([range(25000)]*200).next for x in nextrange(): d.get(x) 100 loops, best of 3: 10.9 msec per loop Peter ___ Python-Dev mailing list Python-Dev@python.org http://mail.python.org/mailman/listinfo/python-dev Unsubscribe: http://mail.python.org/mailman/options/python-dev/archive%40mail-archive.com
Re: [Python-Dev] [Python-checkins] python/dist/src/Lib urllib.py, 1.169, 1.170
Am Samstag, 10. September 2005 04:27 schrieb [EMAIL PROTECTED]:
Update of /cvsroot/python/python/dist/src/Lib
In directory sc8-pr-cvs1.sourceforge.net:/tmp/cvs-serv3622
Modified Files:
urllib.py
Log Message:
Simplify and speed-up quote_plus().
Index: urllib.py
===
RCS file: /cvsroot/python/python/dist/src/Lib/urllib.py,v
retrieving revision 1.169
retrieving revision 1.170
diff -u -d -r1.169 -r1.170
--- urllib.py 9 Sep 2005 22:27:13 - 1.169
+++ urllib.py 10 Sep 2005 02:27:41 - 1.170
@@ -1115,12 +1115,9 @@
def quote_plus(s, safe = ''):
Quote the query fragment of a URL; replacing ' ' with '+'
if ' ' in s:
-l = s.split(' ')
-for i in range(len(l)):
-l[i] = quote(l[i], safe)
-return '+'.join(l)
-else:
-return quote(s, safe)
+s = s.replace(' ', '+')
+safe += '+'
+return quote(s, safe)
def urlencode(query,doseq=0):
Encode a sequence of two-element tuples or dictionary into a URL
query string.
You also change the behaviour. Before:
urllib.quote_plus(alpha+beta gamma)
'alpha%2Bbeta+gamma'
After:
urllib.quote_plus(alpha+beta gamma)
'alpha+beta+gamma'
Is that intentional? If so, you also have to update the documentation, which
currently reads:
quote_plus(string[, safe])
... Plus signs in the original string are escaped unless they are included in
safe. ...
Peter
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