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

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.

diff --git a/Objects/object.c b/Objects/object.c
index ba736a9d93d552f6f868137f6109fc3b13f15777..9108fd431ac3da682a5389d1ef17cd367e3c5c66 100644 (file)
--- 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))