https://github.com/python/cpython/commit/f7bb658124aba74be4c13f498bf46cfded710ef9
commit: f7bb658124aba74be4c13f498bf46cfded710ef9
branch: main
author: Sergey B Kirpichev <[email protected]>
committer: gpshead <[email protected]>
date: 2024-11-23T23:37:37-08:00
summary:
gh-113841: fix possible undefined division by 0 in _Py_c_pow() (GH-127211)
`x**y == 1/x**-y ` thus changing `/=` to `*=` by negating the exponent.
files:
A
Misc/NEWS.d/next/Core_and_Builtins/2024-11-24-07-01-28.gh-issue-113841.WFg-Bu.rst
M Lib/test/test_complex.py
M Objects/complexobject.c
diff --git a/Lib/test/test_complex.py b/Lib/test/test_complex.py
index ecc97315e50d31..c51327c7f33a0a 100644
--- a/Lib/test/test_complex.py
+++ b/Lib/test/test_complex.py
@@ -338,6 +338,11 @@ def test_pow(self):
except OverflowError:
pass
+ # gh-113841: possible undefined division by 0 in _Py_c_pow()
+ x, y = 9j, 33j**3
+ with self.assertRaises(OverflowError):
+ x**y
+
def test_pow_with_small_integer_exponents(self):
# Check that small integer exponents are handled identically
# regardless of their type.
diff --git
a/Misc/NEWS.d/next/Core_and_Builtins/2024-11-24-07-01-28.gh-issue-113841.WFg-Bu.rst
b/Misc/NEWS.d/next/Core_and_Builtins/2024-11-24-07-01-28.gh-issue-113841.WFg-Bu.rst
new file mode 100644
index 00000000000000..2b07fdfcc6b527
--- /dev/null
+++
b/Misc/NEWS.d/next/Core_and_Builtins/2024-11-24-07-01-28.gh-issue-113841.WFg-Bu.rst
@@ -0,0 +1,2 @@
+Fix possible undefined behavior division by zero in :class:`complex`'s
+:c:func:`_Py_c_pow`.
diff --git a/Objects/complexobject.c b/Objects/complexobject.c
index 7b4948fc8ebe3d..9faa57519a424b 100644
--- a/Objects/complexobject.c
+++ b/Objects/complexobject.c
@@ -168,7 +168,7 @@ _Py_c_pow(Py_complex a, Py_complex b)
at = atan2(a.imag, a.real);
phase = at*b.real;
if (b.imag != 0.0) {
- len /= exp(at*b.imag);
+ len *= exp(-at*b.imag);
phase += b.imag*log(vabs);
}
r.real = len*cos(phase);
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