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[3.6] bpo-31482: Missing bytes support for random.seed() version 1 (GH-3614) #3629

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[3.6] bpo-31482: Missing bytes support for random.seed() version 1 (GH-3614) #3629

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5 changes: 3 additions & 2 deletions Lib/random.py
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Original file line number Diff line number Diff line change
Expand Up @@ -109,9 +109,10 @@ def seed(self, a=None, version=2):
"""

if version == 1 and isinstance(a, (str, bytes)):
a = a.decode('latin-1') if isinstance(a, bytes) else a
x = ord(a[0]) << 7 if a else 0
for c in a:
x = ((1000003 * x) ^ ord(c)) & 0xFFFFFFFFFFFFFFFF
for c in map(ord, a):
x = ((1000003 * x) ^ c) & 0xFFFFFFFFFFFFFFFF
x ^= len(a)
a = -2 if x == -1 else x

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27 changes: 27 additions & 0 deletions Lib/test/test_random.py
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Expand Up @@ -423,6 +423,33 @@ def test_bug_27706(self):
['0x1.b0580f98a7dbep-1', '0x1.84129978f9c1ap-1',
'0x1.aeaa51052e978p-2', '0x1.092178fb945a6p-2'])

def test_bug_31482(self):
# Verify that version 1 seeds are unaffected by hash randomization
# when the seeds are expressed as bytes rather than strings.
# The hash(b) values listed are the Python2.7 hash() values
# which were used for seeding.

self.gen.seed(b'nofar', version=1) # hash('nofar') == 5990528763808513177
self.assertEqual([self.gen.random().hex() for i in range(4)],
['0x1.8645314505ad7p-1', '0x1.afb1f82e40a40p-5',
'0x1.2a59d2285e971p-1', '0x1.56977142a7880p-6'])

self.gen.seed(b'rachel', version=1) # hash('rachel') == -9091735575445484789
self.assertEqual([self.gen.random().hex() for i in range(4)],
['0x1.0b294cc856fcdp-1', '0x1.2ad22d79e77b8p-3',
'0x1.3052b9c072678p-2', '0x1.578f332106574p-3'])

self.gen.seed(b'', version=1) # hash('') == 0
self.assertEqual([self.gen.random().hex() for i in range(4)],
['0x1.b0580f98a7dbep-1', '0x1.84129978f9c1ap-1',
'0x1.aeaa51052e978p-2', '0x1.092178fb945a6p-2'])

b = b'\x00\x20\x40\x60\x80\xA0\xC0\xE0\xF0'
self.gen.seed(b, version=1) # hash(b) == 5015594239749365497
self.assertEqual([self.gen.random().hex() for i in range(4)],
['0x1.52c2fde444d23p-1', '0x1.875174f0daea4p-2',
'0x1.9e9b2c50e5cd2p-1', '0x1.fa57768bd321cp-2'])

def test_setstate_first_arg(self):
self.assertRaises(ValueError, self.gen.setstate, (1, None, None))

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1 change: 1 addition & 0 deletions Misc/NEWS.d/next/Library/2017-09-16-01-53-11.bpo-31482.39s5dS.rst
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@@ -0,0 +1 @@
``random.seed()`` now works with bytes in version=1