[New-bugs-announce] [issue14999] ctypes ArgumentError lists arguments from 1, not 0
report at bugs.python.org
Mon Jun 4 07:50:05 CEST 2012
New submission from Timothy Pederick <pederick at gmail.com>:
The ctypes ArgumentError exception indicates the location of the problem by argument number. It counts arguments starting from 1, not 0 as is typical in Python.
An example (anonymised) traceback:
Traceback (most recent call last):
foreign_function(a, b, c, d)
ctypes.ArgumentError: argument 2: <class 'TypeError'>: wrong type
The error here was with the argument "b".
Standard, zero-indexed Python counting would suggest that argument 2 should mean "c", and "b" would be argument 1.
This may be as intended, but for me it violates the principle of least surprise.
I *think* this is the vicinity of the bug:
_ctypes_extend_error(PyExc_ArgError, "argument %d: ", i+1);
If I'm right and the "i+1" (here and/or in subsequent lines) is the cause, that definitely makes it look intentional.
title: ctypes ArgumentError lists arguments from 1, not 0
versions: Python 3.2
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