Issue #789290: make sure that hash(2**63) == hash(2.**63) on 64-bit

mark.dickinson · mark.dickinson · commit 120a18dbf0f1 · 2009-02-08T14:42:28.000Z
platforms. The previous code was fragile, depending on the twin accidents that: (1) in C, casting the double value 2.**63 to long returns the integer value -2**63, and (2) in Python, hash(-2**63) == hash(2**63). There's already a test for this in test_hash. git-svn-id: http://svn.python.org/projects/python/trunk@69436 6015fed2-1504-0410-9fe1-9d1591cc4771
diff --git a/Objects/object.c b/Objects/object.c
@@ -1028,7 +1028,7 @@ _Py_HashDouble(double v)
 	fractpart = modf(v, &intpart);
 	if (fractpart == 0.0) {
 		/* This must return the same hash as an equal int or long. */
-		if (intpart > LONG_MAX || -intpart > LONG_MAX) {
+		if (intpart > LONG_MAX/2 || -intpart > LONG_MAX/2) {
 			/* Convert to long and use its hash. */
 			PyObject *plong;	/* converted to Python long */
 			if (Py_IS_INFINITY(intpart))
