This patch addresses two main issues: (1) There exist some non-fatal

errors in some of the hash algorithms. For exmaple, in float_hash and
complex_hash a certain part of the value is not included in the hash
calculation. See Tim's, Guido's, and my discussion of this on
python-dev in May under the title "fix float_hash and complex_hash for
64-bit *nix"

(2) The hash algorithms that use pointers (e.g. func_hash, code_hash)
are universally not correct on Win64 (they assume that sizeof(long) ==
sizeof(void*))

As well, this patch significantly cleans up the hash code. It adds the
two function _Py_HashDouble and _PyHash_VoidPtr that the various
hashing routine are changed to use.

These help maintain the hash function invariant: (a==b) =>
(hash(a)==hash(b))) I have added Lib/test/test_hash.py and
Lib/test/output/test_hash to test this for some cases.

1 files changed, 8 insertions, 2 deletions

diff --git a/Objects/methodobject.c b/Objects/methodobject.c
index 8b67a87e79..580bb2f25b 100644
--- a/Objects/methodobject.c
+++ b/Objects/methodobject.c
@@ -172,7 +172,7 @@ static long
 meth_hash(a)
 	PyCFunctionObject *a;
 {
-	long x;
+	long x,y;
 	if (a->m_self == NULL)
 		x = 0;
 	else {
@@ -180,7 +180,13 @@ meth_hash(a)
 		if (x == -1)
 			return -1;
 	}
-	return x ^ (long) a->m_ml->ml_meth;
+	y = _Py_HashPointer(a->m_ml->ml_meth);
+	if (y == -1)
+		return -1;
+	x ^= y;
+	if (x == -1)
+		x = -2;
+	return x;
 }
 
 PyTypeObject PyCFunction_Type = {