address review: correct zero division case and add inf**1j test

Author: skirpichev

Include/internal/pycore_complexobject.h

@@ -45,6 +45,12 @@ _Py_c_isfinite(Py_complex a)
     return isfinite(a.real) && isfinite(a.imag);
 }
 
+static inline bool
+_Py_c_iszero(Py_complex a)
+{
+    return a.real == 0.0 && a.imag == 0.0;
+}
+
 #ifdef __cplusplus
 }
 #endif

Lib/test/test_complex.py

@@ -370,6 +370,9 @@ def test_pow(self):
         r = pow(complex(INF), 2.25)  # generic algorithm
         self.assertEqual(r.real, INF)
         self.assertTrue(isnan(r.imag))
+        r = pow(complex(INF), 1j)
+        self.assertTrue(isnan(r.real))
+        self.assertTrue(isnan(r.imag))
 
         a = 3.33+4.43j
         self.assertEqual(a ** 0j, 1)

Objects/complexobject.c

@@ -301,7 +301,7 @@ _Py_c_quot(Py_complex a, Py_complex b)
 {
     Py_complex r = c_quot(a, b);
 
-    if (_Py_c_isnan(r) && b.real == 0 && b.imag == 0) {
+    if (_Py_c_isnan(r) && _Py_c_iszero(b)) {
         errno = EDOM;
         r.real = r.imag = 0.0; /* and set r as documented */
     }
@@ -314,11 +314,11 @@ c_pow(Py_complex a, Py_complex b)
     Py_complex r;
     double vabs,len,at,phase;
 
-    if (b.real == 0. && b.imag == 0.) {
+    if (_Py_c_iszero(b)) {
         r.real = 1.;
         r.imag = 0.;
     }
-    else if (a.real == 0. && a.imag == 0.) {
+    else if (_Py_c_iszero(a)) {
         if (b.imag != 0. || b.real < 0.) {
             r.real = NAN;
             r.imag = NAN;
@@ -780,7 +780,7 @@ complex_pow(PyObject *v, PyObject *w, PyObject *z)
     else {
         p = c_pow(a, b);
     }
-    if (_Py_c_isnan(p) && a.real == 0 && a.imag == 0) {
+    if (_Py_c_isnan(p) && _Py_c_iszero(a) && (b.imag || b.real < 0)) {
         PyErr_SetString(PyExc_ZeroDivisionError,
                         "zero to a negative or complex power");
         return NULL;