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[3.8] bpo-35431: Simplify negativity checks in math.comb and math.perm. (GH-13870) #14125

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Merged
mdickinson merged 1 commit into from
Jun 16, 2019
Merged

[3.8] bpo-35431: Simplify negativity checks in math.comb and math.perm. (GH-13870) #14125

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26 changes: 16 additions & 10 deletions Modules/mathmodule.c
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Original file line number Diff line number Diff line change
Expand Up @@ -3056,6 +3056,12 @@ math_perm_impl(PyObject *module, PyObject *n, PyObject *k)
"n must be a non-negative integer");
goto error;
}
if (Py_SIZE(k) < 0) {
PyErr_SetString(PyExc_ValueError,
"k must be a non-negative integer");
goto error;
}

cmp = PyObject_RichCompareBool(n, k, Py_LT);
if (cmp != 0) {
if (cmp > 0) {
Expand All @@ -3072,11 +3078,8 @@ math_perm_impl(PyObject *module, PyObject *n, PyObject *k)
LLONG_MAX);
goto error;
}
else if (overflow < 0 || factors < 0) {
if (!PyErr_Occurred()) {
PyErr_SetString(PyExc_ValueError,
"k must be a non-negative integer");
}
else if (factors == -1) {
/* k is nonnegative, so a return value of -1 can only indicate error */
goto error;
}

Expand Down Expand Up @@ -3176,6 +3179,12 @@ math_comb_impl(PyObject *module, PyObject *n, PyObject *k)
"n must be a non-negative integer");
goto error;
}
if (Py_SIZE(k) < 0) {
PyErr_SetString(PyExc_ValueError,
"k must be a non-negative integer");
goto error;
}

/* k = min(k, n - k) */
temp = PyNumber_Subtract(n, k);
if (temp == NULL) {
Expand Down Expand Up @@ -3204,11 +3213,8 @@ math_comb_impl(PyObject *module, PyObject *n, PyObject *k)
LLONG_MAX);
goto error;
}
else if (overflow < 0 || factors < 0) {
if (!PyErr_Occurred()) {
PyErr_SetString(PyExc_ValueError,
"k must be a non-negative integer");
}
if (factors == -1) {
/* k is nonnegative, so a return value of -1 can only indicate error */
goto error;
}

Expand Down