bpo-29960 _random.Random corrupted on exception in setstate(). #1019
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@bladebryan, thanks for your PR! By analyzing the history of the files in this pull request, we identified @rhettinger, @serhiy-storchaka and @benjaminp to be potential reviewers. |
Lib/test/test_random.py
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| @@ -446,7 +451,7 @@ def test_setstate_middle_arg(self): | |||
| state_values[-1] = float('nan') | |||
| state = (int(x) for x in state_values) | |||
| self.assertRaises(TypeError, self.gen.setstate, (2, state, None)) | |||
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Is there a space added?
| @@ -436,6 +437,10 @@ def test_setstate_middle_arg(self): | |||
| self.gen.setstate((2, (1,)*624+(625,), None)) | |||
| with self.assertRaises((ValueError, OverflowError)): | |||
| self.gen.setstate((2, (1,)*624+(-1,), None)) | |||
| # Failed calls to setstate() should not have changed the state. | |||
| bits100 = self.gen.getrandbits(100) | |||
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I don't think that the test is correct. Why not generating bits before calling setstate()?
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I'm testing that the failed calls to setstate() did not change the state. I save the initial state, then the failed calls happen. Now I want to know if I'm still in the initial state. I don't check for state equality because a generator's state might not support equality test. I test by generating bits, restoring the initial state, and generating what should be the same bits.
I'm not testing the succeeding call to setstate(). There are other test cases for that, so I assume it works.
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I confirm that the test is correct.
Misc/NEWS
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| @@ -10,6 +10,9 @@ What's New in Python 3.7.0 alpha 1? | |||
| Core and Builtins | |||
| ----------------- | |||
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| - bpo-29960: Preserve generator state when _random.Random.setstate() | |||
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This entry should be added in the "Library" section rather than "Core and Builtins".
serhiy-storchaka
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type-bug
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Thank you for your contribution @bladebryan! Do you mind to backport your chages? |
…ythonGH-1019). (cherry picked from commit 9616a82)
…ythonGH-1019). (cherry picked from commit 9616a82)
…ythonGH-1019). (cherry picked from commit 9616a82)
Changes the _random.Random.setstate() function so that if it raises an exception the state of the generator is unchanged.