bpo-44018: random.seed() no longer mutates its inputs (GH-25856) (GH-25872)
diff --git a/Lib/random.py b/Lib/random.py
index 3a835ae..1310a2d 100644
--- a/Lib/random.py
+++ b/Lib/random.py
@@ -154,8 +154,7 @@ def seed(self, a=None, version=2):
elif version == 2 and isinstance(a, (str, bytes, bytearray)):
if isinstance(a, str):
a = a.encode()
- a += _sha512(a).digest()
- a = int.from_bytes(a, 'big')
+ a = int.from_bytes(a + _sha512(a).digest(), 'big')
elif not isinstance(a, (type(None), int, float, str, bytes, bytearray)):
_warn('Seeding based on hashing is deprecated\n'
diff --git a/Lib/test/test_random.py b/Lib/test/test_random.py
index 6690886..5354edd 100644
--- a/Lib/test/test_random.py
+++ b/Lib/test/test_random.py
@@ -57,6 +57,11 @@ def __hash__(self):
self.assertRaises(TypeError, self.gen.seed, 1, 2, 3, 4)
self.assertRaises(TypeError, type(self.gen), [])
+ def test_seed_no_mutate_bug_44018(self):
+ a = bytearray(b'1234')
+ self.gen.seed(a)
+ self.assertEqual(a, bytearray(b'1234'))
+
@unittest.mock.patch('random._urandom') # os.urandom
def test_seed_when_randomness_source_not_found(self, urandom_mock):
# Random.seed() uses time.time() when an operating system specific
diff --git a/Misc/NEWS.d/next/Library/2021-05-03-10-07-43.bpo-44018.VDyW8f.rst b/Misc/NEWS.d/next/Library/2021-05-03-10-07-43.bpo-44018.VDyW8f.rst
new file mode 100644
index 0000000..87c7d83
--- /dev/null
+++ b/Misc/NEWS.d/next/Library/2021-05-03-10-07-43.bpo-44018.VDyW8f.rst
@@ -0,0 +1 @@
+random.seed() no longer mutates bytearray inputs.