[Python-checkins] bpo-31482: Missing bytes support for random.seed() version 1 (#3614)

[Raymond Hettinger]

https://github.com/python/cpython/commit/132a7d7cdbc7cb89fa1c1f4e8192241c3d68f549
commit: 132a7d7cdbc7cb89fa1c1f4e8192241c3d68f549
branch: master
author: Raymond Hettinger <rhettinger at users.noreply.github.com>
committer: GitHub <noreply at github.com>
date: 2017-09-17T09:04:30-07:00
summary:

bpo-31482:  Missing bytes support for random.seed() version 1 (#3614)

bpo-31482: Missing bytes support for random.seed() version 1 #3614

files:
A Misc/NEWS.d/next/Library/2017-09-16-01-53-11.bpo-31482.39s5dS.rst
M Lib/random.py
M Lib/test/test_random.py

diff --git a/Lib/random.py b/Lib/random.py
index 01c0c3d25fb..91065b7e303 100644
--- a/Lib/random.py
+++ b/Lib/random.py
@@ -110,9 +110,10 @@ 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
 
diff --git a/Lib/test/test_random.py b/Lib/test/test_random.py
index fbb1cf6696e..5d12aee1695 100644
--- a/Lib/test/test_random.py
+++ b/Lib/test/test_random.py
@@ -430,6 +430,33 @@ 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))
 
diff --git a/Misc/NEWS.d/next/Library/2017-09-16-01-53-11.bpo-31482.39s5dS.rst b/Misc/NEWS.d/next/Library/2017-09-16-01-53-11.bpo-31482.39s5dS.rst
new file mode 100644
index 00000000000..ed7a4175cd7
--- /dev/null
+++ b/Misc/NEWS.d/next/Library/2017-09-16-01-53-11.bpo-31482.39s5dS.rst
@@ -0,0 +1 @@
+``random.seed()`` now works with bytes in version=1