[issue44954] Bug in float.fromhex
Pedro Gimeno added the comment: > @Pedro Thanks again for the report! Just out of curiosity, how did you manage > to find this? I'm writing a C strtod implementation and I was adding corner cases to the unit testing (now published here: https://codeberg.org/pgimeno/ACSL/src/branch/master/tests/test-strtod.c). Sometimes I get confused by whether to add one or subtract one to the exponent as digits are moved, and since I have an interactive Python shell always open as a calculator, I used it to make sure that the test I was writing had the correct exponent. But the result I got was not the one I expected, and upon verification, I soon became convinced that it was a bug, so I dug a bit more (at first I didn't notice it only happened if the leading zero was left out) and finally submitted the bug. Thanks for the quick fix, by the way. -- resolution: fixed -> status: closed -> open type: behavior -> versions: -Python 3.10, Python 3.11 ___ Python tracker <https://bugs.python.org/issue44954> ___ ___ Python-bugs-list mailing list Unsubscribe: https://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com
[issue44954] Bug in float.fromhex
New submission from Pedro Gimeno :
>>> float.fromhex('0x0.8p-1074')
0.0
>>> float.fromhex('0x.8p-1074')
5e-324
One of them is obviously wrong. It's the second one, because:
- The smallest denormal is 0x1p-1074
- Therefore, 0x0.8p-1074 is a tie for rounding purposes.
- The digit in the last place is even because the number is zero, and there is
a tie, which implies rounding down.
--
components: Library (Lib)
messages: 399909
nosy: pgimeno
priority: normal
severity: normal
status: open
title: Bug in float.fromhex
versions: Python 3.9
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[issue38800] Resume position for UTF-8 codec error handler not working
Pedro Gimeno added the comment: Python 3.5 from Debian stretch (oldstable). You're right, I can't reproduce it in 3.7 from Buster. Sorry for the bogus report. -- ___ Python tracker <https://bugs.python.org/issue38800> ___ ___ Python-bugs-list mailing list Unsubscribe: https://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com
[issue38800] Resume position for UTF-8 codec error handler not working
Pedro Gimeno added the comment: I forgot the quotes in the assertion, it should have been "b'xz'". -- ___ Python tracker <https://bugs.python.org/issue38800> ___ ___ Python-bugs-list mailing list Unsubscribe: https://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com
[issue38800] Resume position for UTF-8 codec error handler not working
New submission from Pedro Gimeno :
When implementing an error handler, it must return a tuple consisting of a
substitution string and a position where to resume decoding. In the case of the
UTF-8 codec, the resume position is ignored, and it always resumes immediately
after the character that caused the error.
To reproduce, use this code:
import codecs
codecs.register_error('err', lambda err: (b'x', err.end + 1))
assert repr(u'\uDD00yz'.encode('utf8', errors='err')) == b'xz'
The above code fails the assertion because the result is b'xyz'.
It works OK for some other codecs. I have not tried to make an exhaustive list
of which ones work and which ones don't, therefore this problem might apply to
others.
--
messages: 356610
nosy: pgimeno
priority: normal
severity: normal
status: open
title: Resume position for UTF-8 codec error handler not working
type: behavior
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[issue2506] Add mechanism to disable optimizations
Pedro Gimeno added the comment: I consider peephole optimization when no optimization was requested a bug. Documentation for -O says it Turns on basic optimizations. Peephole optimization is a basic optimization, yet it is performed even when no basic optimizations were requested. No need to add a switch. Just don't optimize if not requested. -- nosy: +pgimeno ___ Python tracker rep...@bugs.python.org http://bugs.python.org/issue2506 ___ ___ Python-bugs-list mailing list Unsubscribe: https://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com
