New restriction on pow(x, y, z): If z is not None, x and y must be of

integer types, and y must be >= 0.  See discussion at
http://sf.net/tracker/index.php?func=detail&aid=457066&group_id=5470&atid=105470

3 files changed, 20 insertions, 18 deletions

diff --git a/Objects/floatobject.c b/Objects/floatobject.c
index 39eba8e..8cd26b4 100644
--- a/Objects/floatobject.c
+++ b/Objects/floatobject.c
@@ -492,11 +492,13 @@ static PyObject *
 float_pow(PyObject *v, PyObject *w, PyObject *z)
 {
 	double iv, iw, ix;
- /* XXX Doesn't handle overflows if z!=None yet; it may never do so :(
-  * The z parameter is really only going to be useful for integers and
-  * long integers.  Maybe something clever with logarithms could be done.
-  * [AMK]
-  */
+
+	if ((PyObject *)z != Py_None) {
+		PyErr_SetString(PyExc_TypeError,
+			"3rd argument to floating pow() must be None");
+		return NULL;
+	}
+
 	CONVERT_TO_DOUBLE(v, iv);
 	CONVERT_TO_DOUBLE(w, iw);
 
@@ -538,16 +540,6 @@ float_pow(PyObject *v, PyObject *w, PyObject *z)
 		PyErr_SetFromErrno(PyExc_OverflowError);
 		return NULL;
 	}
-	if ((PyObject *)z != Py_None) {
-		double iz;
-		CONVERT_TO_DOUBLE(z, iz);
-		PyFPE_START_PROTECT("pow", return 0)
-	 	ix = fmod(ix, iz);	/* XXX To Be Rewritten */
-	 	if (ix != 0 && ((iv < 0 && iz > 0) || (iv > 0 && iz < 0) )) {
-		     ix += iz;
-		}
-  		PyFPE_END_PROTECT(ix)
-	}
 	return PyFloat_FromDouble(ix);
 }
 
diff --git a/Objects/intobject.c b/Objects/intobject.c
index 108e658..eaf869f 100644
--- a/Objects/intobject.c
+++ b/Objects/intobject.c
@@ -575,6 +575,11 @@ int_pow(PyIntObject *v, PyIntObject *w, PyIntObject *z)
 	CONVERT_TO_LONG(v, iv);
 	CONVERT_TO_LONG(w, iw);
 	if (iw < 0) {
+		if ((PyObject *)z != Py_None) {
+			PyErr_SetString(PyExc_TypeError, "integer pow() arg "
+			     "3 must not be specified when arg 2 is < 0");
+			return NULL;
+		}
 		/* Return a float.  This works because we know that
 		   this calls float_pow() which converts its
 		   arguments to double. */
diff --git a/Objects/longobject.c b/Objects/longobject.c
index 4209419..4d4a959 100644
--- a/Objects/longobject.c
+++ b/Objects/longobject.c
@@ -1598,12 +1598,17 @@ long_pow(PyObject *v, PyObject *w, PyObject *x)
 	
 	size_b = b->ob_size;
 	if (size_b < 0) {
-		/* Return a float.  This works because we know that
-		   this calls float_pow() which converts its
-		   arguments to double. */
 		Py_DECREF(a);
 		Py_DECREF(b);
 		Py_DECREF(c);
+		if (x != Py_None) {
+			PyErr_SetString(PyExc_TypeError, "integer pow() arg "
+			     "3 must not be specified when arg 2 is < 0");
+			return NULL;
+		}
+		/* Return a float.  This works because we know that
+		   this calls float_pow() which converts its
+		   arguments to double. */
 		return PyFloat_Type.tp_as_number->nb_power(v, w, x);
 	}
 	z = (PyLongObject *)PyLong_FromLong(1L);