Antoine Pitrou | 9e3d27b | 2013-08-05 23:35:43 +0200 | [diff] [blame] | 1 | import gc |
| 2 | import sys |
Antoine Pitrou | acc8cf2 | 2014-07-04 20:24:13 -0400 | [diff] [blame] | 3 | import types |
Antoine Pitrou | 9e3d27b | 2013-08-05 23:35:43 +0200 | [diff] [blame] | 4 | import unittest |
| 5 | import weakref |
| 6 | |
| 7 | from test import support |
| 8 | |
| 9 | |
| 10 | class ClearTest(unittest.TestCase): |
| 11 | """ |
| 12 | Tests for frame.clear(). |
| 13 | """ |
| 14 | |
| 15 | def inner(self, x=5, **kwargs): |
| 16 | 1/0 |
| 17 | |
| 18 | def outer(self, **kwargs): |
| 19 | try: |
| 20 | self.inner(**kwargs) |
| 21 | except ZeroDivisionError as e: |
| 22 | exc = e |
| 23 | return exc |
| 24 | |
| 25 | def clear_traceback_frames(self, tb): |
| 26 | """ |
| 27 | Clear all frames in a traceback. |
| 28 | """ |
| 29 | while tb is not None: |
| 30 | tb.tb_frame.clear() |
| 31 | tb = tb.tb_next |
| 32 | |
| 33 | def test_clear_locals(self): |
| 34 | class C: |
| 35 | pass |
| 36 | c = C() |
| 37 | wr = weakref.ref(c) |
| 38 | exc = self.outer(c=c) |
| 39 | del c |
| 40 | support.gc_collect() |
| 41 | # A reference to c is held through the frames |
| 42 | self.assertIsNot(None, wr()) |
| 43 | self.clear_traceback_frames(exc.__traceback__) |
| 44 | support.gc_collect() |
| 45 | # The reference was released by .clear() |
| 46 | self.assertIs(None, wr()) |
| 47 | |
| 48 | def test_clear_generator(self): |
| 49 | endly = False |
| 50 | def g(): |
| 51 | nonlocal endly |
| 52 | try: |
| 53 | yield |
| 54 | inner() |
| 55 | finally: |
| 56 | endly = True |
| 57 | gen = g() |
| 58 | next(gen) |
| 59 | self.assertFalse(endly) |
| 60 | # Clearing the frame closes the generator |
| 61 | gen.gi_frame.clear() |
| 62 | self.assertTrue(endly) |
| 63 | |
| 64 | def test_clear_executing(self): |
| 65 | # Attempting to clear an executing frame is forbidden. |
| 66 | try: |
| 67 | 1/0 |
| 68 | except ZeroDivisionError as e: |
| 69 | f = e.__traceback__.tb_frame |
| 70 | with self.assertRaises(RuntimeError): |
| 71 | f.clear() |
| 72 | with self.assertRaises(RuntimeError): |
| 73 | f.f_back.clear() |
| 74 | |
| 75 | def test_clear_executing_generator(self): |
| 76 | # Attempting to clear an executing generator frame is forbidden. |
| 77 | endly = False |
| 78 | def g(): |
| 79 | nonlocal endly |
| 80 | try: |
| 81 | 1/0 |
| 82 | except ZeroDivisionError as e: |
| 83 | f = e.__traceback__.tb_frame |
| 84 | with self.assertRaises(RuntimeError): |
| 85 | f.clear() |
| 86 | with self.assertRaises(RuntimeError): |
| 87 | f.f_back.clear() |
| 88 | yield f |
| 89 | finally: |
| 90 | endly = True |
| 91 | gen = g() |
| 92 | f = next(gen) |
| 93 | self.assertFalse(endly) |
Antoine Pitrou | dbfc129 | 2013-08-06 23:05:23 +0200 | [diff] [blame] | 94 | # Clearing the frame closes the generator |
| 95 | f.clear() |
| 96 | self.assertTrue(endly) |
Antoine Pitrou | 9e3d27b | 2013-08-05 23:35:43 +0200 | [diff] [blame] | 97 | |
| 98 | @support.cpython_only |
| 99 | def test_clear_refcycles(self): |
Antoine Pitrou | 236a547 | 2013-08-06 23:06:59 +0200 | [diff] [blame] | 100 | # .clear() doesn't leave any refcycle behind |
Antoine Pitrou | 9e3d27b | 2013-08-05 23:35:43 +0200 | [diff] [blame] | 101 | with support.disable_gc(): |
| 102 | class C: |
| 103 | pass |
| 104 | c = C() |
| 105 | wr = weakref.ref(c) |
| 106 | exc = self.outer(c=c) |
| 107 | del c |
| 108 | self.assertIsNot(None, wr()) |
| 109 | self.clear_traceback_frames(exc.__traceback__) |
| 110 | self.assertIs(None, wr()) |
| 111 | |
| 112 | |
Antoine Pitrou | acc8cf2 | 2014-07-04 20:24:13 -0400 | [diff] [blame] | 113 | class FrameLocalsTest(unittest.TestCase): |
| 114 | """ |
| 115 | Tests for the .f_locals attribute. |
| 116 | """ |
| 117 | |
| 118 | def make_frames(self): |
| 119 | def outer(): |
| 120 | x = 5 |
| 121 | y = 6 |
| 122 | def inner(): |
| 123 | z = x + 2 |
| 124 | 1/0 |
| 125 | t = 9 |
| 126 | return inner() |
| 127 | try: |
| 128 | outer() |
| 129 | except ZeroDivisionError as e: |
| 130 | tb = e.__traceback__ |
| 131 | frames = [] |
| 132 | while tb: |
| 133 | frames.append(tb.tb_frame) |
| 134 | tb = tb.tb_next |
| 135 | return frames |
| 136 | |
| 137 | def test_locals(self): |
| 138 | f, outer, inner = self.make_frames() |
| 139 | outer_locals = outer.f_locals |
| 140 | self.assertIsInstance(outer_locals.pop('inner'), types.FunctionType) |
| 141 | self.assertEqual(outer_locals, {'x': 5, 'y': 6}) |
| 142 | inner_locals = inner.f_locals |
| 143 | self.assertEqual(inner_locals, {'x': 5, 'z': 7}) |
| 144 | |
| 145 | def test_clear_locals(self): |
| 146 | # Test f_locals after clear() (issue #21897) |
| 147 | f, outer, inner = self.make_frames() |
| 148 | outer.clear() |
| 149 | inner.clear() |
| 150 | self.assertEqual(outer.f_locals, {}) |
| 151 | self.assertEqual(inner.f_locals, {}) |
| 152 | |
| 153 | def test_locals_clear_locals(self): |
| 154 | # Test f_locals before and after clear() (to exercise caching) |
| 155 | f, outer, inner = self.make_frames() |
| 156 | outer.f_locals |
| 157 | inner.f_locals |
| 158 | outer.clear() |
| 159 | inner.clear() |
| 160 | self.assertEqual(outer.f_locals, {}) |
| 161 | self.assertEqual(inner.f_locals, {}) |
| 162 | |
| 163 | |
Antoine Pitrou | 9e3d27b | 2013-08-05 23:35:43 +0200 | [diff] [blame] | 164 | def test_main(): |
| 165 | support.run_unittest(__name__) |
| 166 | |
| 167 | if __name__ == "__main__": |
| 168 | test_main() |