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Incorrect warning when assign an unsigned integer member #114388
Description
Assigning a negative value to an unsigned integer member can emit a RuntimeWarning.
$ ./python -Wa
>>> import _testcapi
>>> ts = _testcapi._test_structmembersType_NewAPI()
>>> ts.T_UBYTE = -42
<stdin>:1: RuntimeWarning: Truncation of value to unsigned char
>>> ts.T_USHORT = -42
<stdin>:1: RuntimeWarning: Truncation of value to unsigned short
>>> ts.T_UINT = -42
<stdin>:1: RuntimeWarning: Writing negative value into unsigned field
<stdin>:1: RuntimeWarning: Truncation of value to unsigned int
>>> ts.T_ULONG = -42
<stdin>:1: RuntimeWarning: Writing negative value into unsigned field(And for T_ULONGLONG it raises an OverflowError, but this is perhaps another issue).
The first issue is that it emits two warnings for T_UINT. It is also weird that warnings are different.
The second issue is that if the value is not an int subclass, it emits a warning also for positive values for T_UINT and T_ULONG:
>>> class Index:
... def __init__(self, value):
... self.value = value
... def __index__(self):
... return self.value
...
>>> ts.T_UBYTE = Index(42)
>>> ts.T_USHORT = Index(42)
>>> ts.T_UINT = Index(42)
<stdin>:1: RuntimeWarning: Writing negative value into unsigned field
>>> ts.T_ULONG = Index(42)
<stdin>:1: RuntimeWarning: Writing negative value into unsigned field(No warning is emitted for assigning a negative index to T_ULONGLONG, but this is perhaps another issue).
Activity
pythongh-114388: Fix warnings when assign an unsigned integer member
gh-114388: Fix warnings when assign an unsigned integer member (GH-11…
pythongh-114388: Fix an error in pythonGH-114391
[3.12] pythongh-114388: Fix warnings when assign an unsigned integer …
[3.11] pythongh-114388: Fix warnings when assign an unsigned integer …
gh-114388: Fix an error in GH-114391 (GH-115000)
[3.12] gh-114388: Fix warnings when assign an unsigned integer member (…
[3.11] gh-114388: Fix warnings when assign an unsigned integer member (…
pythongh-114388: Fix warnings when assign an unsigned integer member (p…
pythongh-114388: Fix an error in pythonGH-114391 (pythonGH-115000)
pythongh-114388: Fix warnings when assign an unsigned integer member (p…
pythongh-114388: Fix an error in pythonGH-114391 (pythonGH-115000)
encukou commentedon Mar 28, 2024
With this change, there's a new warning emitted for “Writing negative value into unsigned field”.
@zooba, you might be interested in this