diff --git a/Misc/NEWS.d/next/Core and Builtins/2018-01-14-20-32-47.bpo-26163.xv9Iuv.rst b/Misc/NEWS.d/next/Core and Builtins/2018-01-14-20-32-47.bpo-26163.xv9Iuv.rst new file mode 100644 index 00000000000..163b9e02c5a --- /dev/null +++ b/Misc/NEWS.d/next/Core and Builtins/2018-01-14-20-32-47.bpo-26163.xv9Iuv.rst @@ -0,0 +1,2 @@ +Improved frozenset() hash to create more distinct hash values when faced +with datasets containing many similar values. diff --git a/Objects/setobject.c b/Objects/setobject.c index 24272b4d14a..093a15f367f 100644 --- a/Objects/setobject.c +++ b/Objects/setobject.c @@ -790,6 +790,7 @@ frozenset_hash(PyObject *self) hash ^= ((Py_uhash_t)PySet_GET_SIZE(self) + 1) * 1927868237UL; /* Disperse patterns arising in nested frozensets */ + hash ^= (hash >> 11) ^ (~hash >> 25); hash = hash * 69069U + 907133923UL; /* -1 is reserved as an error code */