Fast path for int inputs to math.dist() and math.hypot() (GH-11692)

Author: rhettinger

Lib/test/test_math.py

@@ -766,6 +766,9 @@ def testHypot(self):
             hypot(x=1)
         with self.assertRaises(TypeError):         # Reject values without __float__
             hypot(1.1, 'string', 2.2)
+        int_too_big_for_float = 10 ** (sys.float_info.max_10_exp + 5)
+        with self.assertRaises((ValueError, OverflowError)):
+            hypot(1, int_too_big_for_float)
 
         # Any infinity gives positive infinity.
         self.assertEqual(hypot(INF), INF)
@@ -805,7 +808,8 @@ def testDist(self):
         dist = math.dist
         sqrt = math.sqrt
 
-        # Simple exact case
+        # Simple exact cases
+        self.assertEqual(dist((1.0, 2.0, 3.0), (4.0, 2.0, -1.0)), 5.0)
         self.assertEqual(dist((1, 2, 3), (4, 2, -1)), 5.0)
 
         # Test different numbers of arguments (from zero to nine)
@@ -869,6 +873,11 @@ class T(tuple):
             dist((1, 2, 3), (4, 5, 6, 7))
         with self.assertRaises(TypeError):         # Rejects invalid types
             dist("abc", "xyz")
+        int_too_big_for_float = 10 ** (sys.float_info.max_10_exp + 5)
+        with self.assertRaises((ValueError, OverflowError)):
+            dist((1, int_too_big_for_float), (2, 3))
+        with self.assertRaises((ValueError, OverflowError)):
+            dist((2, 3), (1, int_too_big_for_float))
 
         # Verify that the one dimensional case is equivalent to abs()
         for i in range(20):

Modules/mathmodule.c

@@ -2144,7 +2144,14 @@ math_dist_impl(PyObject *module, PyObject *p, PyObject *q)
         item = PyTuple_GET_ITEM(p, i);
         if (PyFloat_CheckExact(item)) {
             px = PyFloat_AS_DOUBLE(item);
-        } else {
+        }
+        else if (PyLong_CheckExact(item)) {
+            px = PyLong_AsDouble(item);
+            if (px == -1.0 && PyErr_Occurred()) {
+                goto error_exit;
+            }
+        }
+        else {
             px = PyFloat_AsDouble(item);
             if (px == -1.0 && PyErr_Occurred()) {
                 goto error_exit;
@@ -2153,7 +2160,14 @@ math_dist_impl(PyObject *module, PyObject *p, PyObject *q)
         item = PyTuple_GET_ITEM(q, i);
         if (PyFloat_CheckExact(item)) {
             qx = PyFloat_AS_DOUBLE(item);
-        } else {
+        }
+        else if (PyLong_CheckExact(item)) {
+            qx = PyLong_AsDouble(item);
+            if (qx == -1.0 && PyErr_Occurred()) {
+                goto error_exit;
+            }
+        }
+        else {
             qx = PyFloat_AsDouble(item);
             if (qx == -1.0 && PyErr_Occurred()) {
                 goto error_exit;
@@ -2201,7 +2215,14 @@ math_hypot(PyObject *self, PyObject *const *args, Py_ssize_t nargs)
         item = args[i];
         if (PyFloat_CheckExact(item)) {
             x = PyFloat_AS_DOUBLE(item);
-        } else {
+        }
+        else if (PyLong_CheckExact(item)) {
+            x = PyLong_AsDouble(item);
+            if (x == -1.0 && PyErr_Occurred()) {
+                goto error_exit;
+            }
+        }
+        else {
             x = PyFloat_AsDouble(item);
             if (x == -1.0 && PyErr_Occurred()) {
                 goto error_exit;