[Python-checkins] bpo-44704: Make Set._hash consistent with frozenset.__hash__ (GH-27281) (GH-27282)
rhettinger
webhook-mailer at python.org
Wed Jul 21 20:23:48 EDT 2021
https://github.com/python/cpython/commit/4194f1465fa85371dcbead57a54bb06d1f0b97d9
commit: 4194f1465fa85371dcbead57a54bb06d1f0b97d9
branch: 3.10
author: Miss Islington (bot) <31488909+miss-islington at users.noreply.github.com>
committer: rhettinger <rhettinger at users.noreply.github.com>
date: 2021-07-21T19:23:21-05:00
summary:
bpo-44704: Make Set._hash consistent with frozenset.__hash__ (GH-27281) (GH-27282)
files:
A Misc/NEWS.d/next/Library/2021-07-21-23-16-30.bpo-44704.iqHLxQ.rst
M Lib/_collections_abc.py
M Lib/test/test_collections.py
diff --git a/Lib/_collections_abc.py b/Lib/_collections_abc.py
index d92b848e9436f..bff58ad4a7f6a 100644
--- a/Lib/_collections_abc.py
+++ b/Lib/_collections_abc.py
@@ -696,6 +696,7 @@ def _hash(self):
hx = hash(x)
h ^= (hx ^ (hx << 16) ^ 89869747) * 3644798167
h &= MASK
+ h ^= (h >> 11) ^ (h >> 25)
h = h * 69069 + 907133923
h &= MASK
if h > MAX:
diff --git a/Lib/test/test_collections.py b/Lib/test/test_collections.py
index f98048b34a7a1..1f659d7d604e3 100644
--- a/Lib/test/test_collections.py
+++ b/Lib/test/test_collections.py
@@ -1801,6 +1801,18 @@ def __repr__(self):
self.assertTrue(f1 != l1)
self.assertTrue(f1 != l2)
+ def test_Set_hash_matches_frozenset(self):
+ sets = [
+ {}, {1}, {None}, {-1}, {0.0}, {"abc"}, {1, 2, 3},
+ {10**100, 10**101}, {"a", "b", "ab", ""}, {False, True},
+ {object(), object(), object()}, {float("nan")}, {frozenset()},
+ {*range(1000)}, {*range(1000)} - {100, 200, 300},
+ {*range(sys.maxsize - 10, sys.maxsize + 10)},
+ ]
+ for s in sets:
+ fs = frozenset(s)
+ self.assertEqual(hash(fs), Set._hash(fs), msg=s)
+
def test_Mapping(self):
for sample in [dict]:
self.assertIsInstance(sample(), Mapping)
diff --git a/Misc/NEWS.d/next/Library/2021-07-21-23-16-30.bpo-44704.iqHLxQ.rst b/Misc/NEWS.d/next/Library/2021-07-21-23-16-30.bpo-44704.iqHLxQ.rst
new file mode 100644
index 0000000000000..586661876dedb
--- /dev/null
+++ b/Misc/NEWS.d/next/Library/2021-07-21-23-16-30.bpo-44704.iqHLxQ.rst
@@ -0,0 +1 @@
+The implementation of ``collections.abc.Set._hash()`` now matches that of ``frozenset.__hash__()``.
\ No newline at end of file
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