Mercurial > cpython-lru_cache-weakref
diff Objects/object.c @ 51465:bbb8350ddbd2 legacy-trunk
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.
| author | Mark Dickinson <dickinsm@gmail.com> |
|---|---|
| date | Sun, 08 Feb 2009 14:42:28 +0000 |
| parents | e9748db47635 |
| children | 5a72eed1eb1a |
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--- a/Objects/object.c Sun Feb 08 14:38:13 2009 +0000 +++ b/Objects/object.c Sun Feb 08 14:42:28 2009 +0000 @@ -1028,7 +1028,7 @@ 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))