[issue29834] Raise ValueError rather of OverflowError in PyLong_AsUnsignedLong()

[Serhiy Storchaka]

Serhiy Storchaka added the comment:

_Py_Uid_Converter() in Modules/posixmodule.c is not an example because it calls 
PyLong_AsUnsignedLong() only for positive integers > LONG_MAX.

PyLong_AsUnsignedLong() is used not much. The motivation of this issue was that 
if use PyLong_AsUnsignedLong() for converting non-negative by its nature values 
ValueError can be more appropriate since this limitation is not platform or 
implementation dependent. Strictly speaking raising OverflowError for negative 
values doesn't fits the definition of an OverflowError, since the result is not 
large at all.

I was going to investigate all usages of PyLong_AsUnsignedLong() and if in 
majority of them ValueError is appropriate and desirable, changing the 
exception type at that level can make the implementation simpler.

--

___
Python tracker 

___
___
Python-bugs-list mailing list
Unsubscribe: 
https://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com

[issue29834] Raise ValueError rather of OverflowError in PyLong_AsUnsignedLong()

[Raymond Hettinger]

Raymond Hettinger added the comment:

Looking back in time, this API isn't as old as I thought.  The other concerns 
about breaking a published API still stand.

--
nosy:  -gvanrossum

___
Python tracker 

___
___
Python-bugs-list mailing list
Unsubscribe: 
https://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com

[issue29834] Raise ValueError rather of OverflowError in PyLong_AsUnsignedLong()

[Raymond Hettinger]

Raymond Hettinger added the comment:

Strong -1 on this.  For zero benefit, this breaks everything (within Python and 
third-party code) that ever relied on the documented behavior , 
https://docs.python.org/3/c-api/long.html#c.PyLong_AsUnsignedLong .

The cause perfectly fits the definition of an OverflowError:

class OverflowError(ArithmeticError)
 |  Result too large to be represented.

The time to challenge API design decisions is when they are created, not after 
they've been published and relied upon for over decade.

Also, we really don't everyone who writes cross-platform code and tests to have 
to catch both exceptions because they don't know which version is being run.  
This creates yet another barrier to upgrading Python and as far as I can tell 
isn't solving any reported user problem.  Instead, it is second-guessing design 
decisions made long ago.

--
nosy: +gvanrossum, rhettinger

___
Python tracker 

___
___
Python-bugs-list mailing list
Unsubscribe: 
https://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com

[issue29834] Raise ValueError rather of OverflowError in PyLong_AsUnsignedLong()

[Oren Milman]

Oren Milman added the comment:

note that there are functions that rely on the fact that
PyLong_AsUnsignedLong currently raises OverflowError for both cases.

such functions would probably use
PyErr_ExceptionMatches(PyExc_OverflowError)
or something like
PyErr_GivenExceptionMatches(err, PyExc_OverflowError)

_Py_Uid_Converter() (in Modules/posixmodule.c) is an example, but
ISTM there aren't many such functions.

however, this is only in cpython's C code. I don't know how many
functions in cpython's python code rely on this.

also, maybe there is a lot of user code that rely on this?

--

___
Python tracker 

___
___
Python-bugs-list mailing list
Unsubscribe: 
https://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com

[issue29834] Raise ValueError rather of OverflowError in PyLong_AsUnsignedLong()

[Serhiy Storchaka]

New submission from Serhiy Storchaka:

OverflowError is raised when Python integer doesn't fit in C integer type due 
to platform limitations. Different platforms have different limits. But in 
PyLong_AsUnsignedLong() only the upper limit is platform-depended. Negative 
integers always are not accepted. PyLong_AsUnsignedLong() is used for values 
that can be only non-negative. I think that ValueError is more appropriate in 
this case than OverflowError.

--
components: Interpreter Core
messages: 289748
nosy: Oren Milman, serhiy.storchaka
priority: normal
severity: normal
status: open
title: Raise ValueError rather of OverflowError in PyLong_AsUnsignedLong()
type: enhancement
versions: Python 3.7

___
Python tracker 

___
___
Python-bugs-list mailing list
Unsubscribe: 
https://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com