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1import builtins
2import codecs
3import _datetime
4import gc
5import locale
6import operator
7import os
8import random
9import struct
10import subprocess
11import sys
12import sysconfig
13import test.support
14from test import support
15from test.support import os_helper
16from test.support.script_helper import assert_python_ok, assert_python_failure
17from test.support import threading_helper
18from test.support import import_helper
19from test.support import force_not_colorized
20try:
21    from test.support import interpreters
22except ImportError:
23    interpreters = None
24import textwrap
25import unittest
26import warnings
27
28
29def requires_subinterpreters(meth):
30    """Decorator to skip a test if subinterpreters are not supported."""
31    return unittest.skipIf(interpreters is None,
32                           'subinterpreters required')(meth)
33
34
35DICT_KEY_STRUCT_FORMAT = 'n2BI2n'
36
37class DisplayHookTest(unittest.TestCase):
38
39    def test_original_displayhook(self):
40        dh = sys.__displayhook__
41
42        with support.captured_stdout() as out:
43            dh(42)
44
45        self.assertEqual(out.getvalue(), "42\n")
46        self.assertEqual(builtins._, 42)
47
48        del builtins._
49
50        with support.captured_stdout() as out:
51            dh(None)
52
53        self.assertEqual(out.getvalue(), "")
54        self.assertTrue(not hasattr(builtins, "_"))
55
56        # sys.displayhook() requires arguments
57        self.assertRaises(TypeError, dh)
58
59        stdout = sys.stdout
60        try:
61            del sys.stdout
62            self.assertRaises(RuntimeError, dh, 42)
63        finally:
64            sys.stdout = stdout
65
66    def test_lost_displayhook(self):
67        displayhook = sys.displayhook
68        try:
69            del sys.displayhook
70            code = compile("42", "<string>", "single")
71            self.assertRaises(RuntimeError, eval, code)
72        finally:
73            sys.displayhook = displayhook
74
75    def test_custom_displayhook(self):
76        def baddisplayhook(obj):
77            raise ValueError
78
79        with support.swap_attr(sys, 'displayhook', baddisplayhook):
80            code = compile("42", "<string>", "single")
81            self.assertRaises(ValueError, eval, code)
82
83class ActiveExceptionTests(unittest.TestCase):
84    def test_exc_info_no_exception(self):
85        self.assertEqual(sys.exc_info(), (None, None, None))
86
87    def test_sys_exception_no_exception(self):
88        self.assertEqual(sys.exception(), None)
89
90    def test_exc_info_with_exception_instance(self):
91        def f():
92            raise ValueError(42)
93
94        try:
95            f()
96        except Exception as e_:
97            e = e_
98            exc_info = sys.exc_info()
99
100        self.assertIsInstance(e, ValueError)
101        self.assertIs(exc_info[0], ValueError)
102        self.assertIs(exc_info[1], e)
103        self.assertIs(exc_info[2], e.__traceback__)
104
105    def test_exc_info_with_exception_type(self):
106        def f():
107            raise ValueError
108
109        try:
110            f()
111        except Exception as e_:
112            e = e_
113            exc_info = sys.exc_info()
114
115        self.assertIsInstance(e, ValueError)
116        self.assertIs(exc_info[0], ValueError)
117        self.assertIs(exc_info[1], e)
118        self.assertIs(exc_info[2], e.__traceback__)
119
120    def test_sys_exception_with_exception_instance(self):
121        def f():
122            raise ValueError(42)
123
124        try:
125            f()
126        except Exception as e_:
127            e = e_
128            exc = sys.exception()
129
130        self.assertIsInstance(e, ValueError)
131        self.assertIs(exc, e)
132
133    def test_sys_exception_with_exception_type(self):
134        def f():
135            raise ValueError
136
137        try:
138            f()
139        except Exception as e_:
140            e = e_
141            exc = sys.exception()
142
143        self.assertIsInstance(e, ValueError)
144        self.assertIs(exc, e)
145
146
147class ExceptHookTest(unittest.TestCase):
148
149    @force_not_colorized
150    def test_original_excepthook(self):
151        try:
152            raise ValueError(42)
153        except ValueError as exc:
154            with support.captured_stderr() as err:
155                sys.__excepthook__(*sys.exc_info())
156
157        self.assertTrue(err.getvalue().endswith("ValueError: 42\n"))
158
159        self.assertRaises(TypeError, sys.__excepthook__)
160
161    @force_not_colorized
162    def test_excepthook_bytes_filename(self):
163        # bpo-37467: sys.excepthook() must not crash if a filename
164        # is a bytes string
165        with warnings.catch_warnings():
166            warnings.simplefilter('ignore', BytesWarning)
167
168            try:
169                raise SyntaxError("msg", (b"bytes_filename", 123, 0, "text"))
170            except SyntaxError as exc:
171                with support.captured_stderr() as err:
172                    sys.__excepthook__(*sys.exc_info())
173
174        err = err.getvalue()
175        self.assertIn("""  File "b'bytes_filename'", line 123\n""", err)
176        self.assertIn("""    text\n""", err)
177        self.assertTrue(err.endswith("SyntaxError: msg\n"))
178
179    def test_excepthook(self):
180        with test.support.captured_output("stderr") as stderr:
181            with test.support.catch_unraisable_exception():
182                sys.excepthook(1, '1', 1)
183        self.assertTrue("TypeError: print_exception(): Exception expected for " \
184                         "value, str found" in stderr.getvalue())
185
186    # FIXME: testing the code for a lost or replaced excepthook in
187    # Python/pythonrun.c::PyErr_PrintEx() is tricky.
188
189
190class SysModuleTest(unittest.TestCase):
191
192    def tearDown(self):
193        test.support.reap_children()
194
195    def test_exit(self):
196        # call with two arguments
197        self.assertRaises(TypeError, sys.exit, 42, 42)
198
199        # call without argument
200        with self.assertRaises(SystemExit) as cm:
201            sys.exit()
202        self.assertIsNone(cm.exception.code)
203
204        rc, out, err = assert_python_ok('-c', 'import sys; sys.exit()')
205        self.assertEqual(rc, 0)
206        self.assertEqual(out, b'')
207        self.assertEqual(err, b'')
208
209        # gh-125842: Windows uses 32-bit unsigned integers for exit codes
210        # so a -1 exit code is sometimes interpreted as 0xffff_ffff.
211        rc, out, err = assert_python_failure('-c', 'import sys; sys.exit(0xffff_ffff)')
212        self.assertIn(rc, (-1, 0xff, 0xffff_ffff))
213        self.assertEqual(out, b'')
214        self.assertEqual(err, b'')
215
216        # Overflow results in a -1 exit code, which may be converted to 0xff
217        # or 0xffff_ffff.
218        rc, out, err = assert_python_failure('-c', 'import sys; sys.exit(2**128)')
219        self.assertIn(rc, (-1, 0xff, 0xffff_ffff))
220        self.assertEqual(out, b'')
221        self.assertEqual(err, b'')
222
223        # call with integer argument
224        with self.assertRaises(SystemExit) as cm:
225            sys.exit(42)
226        self.assertEqual(cm.exception.code, 42)
227
228        # call with tuple argument with one entry
229        # entry will be unpacked
230        with self.assertRaises(SystemExit) as cm:
231            sys.exit((42,))
232        self.assertEqual(cm.exception.code, 42)
233
234        # call with string argument
235        with self.assertRaises(SystemExit) as cm:
236            sys.exit("exit")
237        self.assertEqual(cm.exception.code, "exit")
238
239        # call with tuple argument with two entries
240        with self.assertRaises(SystemExit) as cm:
241            sys.exit((17, 23))
242        self.assertEqual(cm.exception.code, (17, 23))
243
244        # test that the exit machinery handles SystemExits properly
245        rc, out, err = assert_python_failure('-c', 'raise SystemExit(47)')
246        self.assertEqual(rc, 47)
247        self.assertEqual(out, b'')
248        self.assertEqual(err, b'')
249
250        def check_exit_message(code, expected, **env_vars):
251            rc, out, err = assert_python_failure('-c', code, **env_vars)
252            self.assertEqual(rc, 1)
253            self.assertEqual(out, b'')
254            self.assertTrue(err.startswith(expected),
255                "%s doesn't start with %s" % (ascii(err), ascii(expected)))
256
257        # test that stderr buffer is flushed before the exit message is written
258        # into stderr
259        check_exit_message(
260            r'import sys; sys.stderr.write("unflushed,"); sys.exit("message")',
261            b"unflushed,message")
262
263        # test that the exit message is written with backslashreplace error
264        # handler to stderr
265        check_exit_message(
266            r'import sys; sys.exit("surrogates:\uDCFF")',
267            b"surrogates:\\udcff")
268
269        # test that the unicode message is encoded to the stderr encoding
270        # instead of the default encoding (utf8)
271        check_exit_message(
272            r'import sys; sys.exit("h\xe9")',
273            b"h\xe9", PYTHONIOENCODING='latin-1')
274
275    def test_getdefaultencoding(self):
276        self.assertRaises(TypeError, sys.getdefaultencoding, 42)
277        # can't check more than the type, as the user might have changed it
278        self.assertIsInstance(sys.getdefaultencoding(), str)
279
280    # testing sys.settrace() is done in test_sys_settrace.py
281    # testing sys.setprofile() is done in test_sys_setprofile.py
282
283    def test_switchinterval(self):
284        self.assertRaises(TypeError, sys.setswitchinterval)
285        self.assertRaises(TypeError, sys.setswitchinterval, "a")
286        self.assertRaises(ValueError, sys.setswitchinterval, -1.0)
287        self.assertRaises(ValueError, sys.setswitchinterval, 0.0)
288        orig = sys.getswitchinterval()
289        # sanity check
290        self.assertTrue(orig < 0.5, orig)
291        try:
292            for n in 0.00001, 0.05, 3.0, orig:
293                sys.setswitchinterval(n)
294                self.assertAlmostEqual(sys.getswitchinterval(), n)
295        finally:
296            sys.setswitchinterval(orig)
297
298    def test_getrecursionlimit(self):
299        limit = sys.getrecursionlimit()
300        self.assertIsInstance(limit, int)
301        self.assertGreater(limit, 1)
302
303        self.assertRaises(TypeError, sys.getrecursionlimit, 42)
304
305    def test_setrecursionlimit(self):
306        old_limit = sys.getrecursionlimit()
307        try:
308            sys.setrecursionlimit(10_005)
309            self.assertEqual(sys.getrecursionlimit(), 10_005)
310
311            self.assertRaises(TypeError, sys.setrecursionlimit)
312            self.assertRaises(ValueError, sys.setrecursionlimit, -42)
313        finally:
314            sys.setrecursionlimit(old_limit)
315
316    def test_recursionlimit_recovery(self):
317        if hasattr(sys, 'gettrace') and sys.gettrace():
318            self.skipTest('fatal error if run with a trace function')
319
320        old_limit = sys.getrecursionlimit()
321        def f():
322            f()
323        try:
324            for depth in (50, 75, 100, 250, 1000):
325                try:
326                    sys.setrecursionlimit(depth)
327                except RecursionError:
328                    # Issue #25274: The recursion limit is too low at the
329                    # current recursion depth
330                    continue
331
332                # Issue #5392: test stack overflow after hitting recursion
333                # limit twice
334                with self.assertRaises(RecursionError):
335                    f()
336                with self.assertRaises(RecursionError):
337                    f()
338        finally:
339            sys.setrecursionlimit(old_limit)
340
341    @test.support.cpython_only
342    def test_setrecursionlimit_to_depth(self):
343        # Issue #25274: Setting a low recursion limit must be blocked if the
344        # current recursion depth is already higher than limit.
345
346        old_limit = sys.getrecursionlimit()
347        try:
348            depth = support.get_recursion_depth()
349            with self.subTest(limit=sys.getrecursionlimit(), depth=depth):
350                # depth + 1 is OK
351                sys.setrecursionlimit(depth + 1)
352
353                # reset the limit to be able to call self.assertRaises()
354                # context manager
355                sys.setrecursionlimit(old_limit)
356                with self.assertRaises(RecursionError) as cm:
357                    sys.setrecursionlimit(depth)
358            self.assertRegex(str(cm.exception),
359                             "cannot set the recursion limit to [0-9]+ "
360                             "at the recursion depth [0-9]+: "
361                             "the limit is too low")
362        finally:
363            sys.setrecursionlimit(old_limit)
364
365    def test_getwindowsversion(self):
366        # Raise SkipTest if sys doesn't have getwindowsversion attribute
367        test.support.get_attribute(sys, "getwindowsversion")
368        v = sys.getwindowsversion()
369        self.assertEqual(len(v), 5)
370        self.assertIsInstance(v[0], int)
371        self.assertIsInstance(v[1], int)
372        self.assertIsInstance(v[2], int)
373        self.assertIsInstance(v[3], int)
374        self.assertIsInstance(v[4], str)
375        self.assertRaises(IndexError, operator.getitem, v, 5)
376        self.assertIsInstance(v.major, int)
377        self.assertIsInstance(v.minor, int)
378        self.assertIsInstance(v.build, int)
379        self.assertIsInstance(v.platform, int)
380        self.assertIsInstance(v.service_pack, str)
381        self.assertIsInstance(v.service_pack_minor, int)
382        self.assertIsInstance(v.service_pack_major, int)
383        self.assertIsInstance(v.suite_mask, int)
384        self.assertIsInstance(v.product_type, int)
385        self.assertEqual(v[0], v.major)
386        self.assertEqual(v[1], v.minor)
387        self.assertEqual(v[2], v.build)
388        self.assertEqual(v[3], v.platform)
389        self.assertEqual(v[4], v.service_pack)
390
391        # This is how platform.py calls it. Make sure tuple
392        #  still has 5 elements
393        maj, min, buildno, plat, csd = sys.getwindowsversion()
394
395    def test_call_tracing(self):
396        self.assertRaises(TypeError, sys.call_tracing, type, 2)
397
398    @unittest.skipUnless(hasattr(sys, "setdlopenflags"),
399                         'test needs sys.setdlopenflags()')
400    def test_dlopenflags(self):
401        self.assertTrue(hasattr(sys, "getdlopenflags"))
402        self.assertRaises(TypeError, sys.getdlopenflags, 42)
403        oldflags = sys.getdlopenflags()
404        self.assertRaises(TypeError, sys.setdlopenflags)
405        sys.setdlopenflags(oldflags+1)
406        self.assertEqual(sys.getdlopenflags(), oldflags+1)
407        sys.setdlopenflags(oldflags)
408
409    @test.support.refcount_test
410    def test_refcount(self):
411        # n here originally had to be a global in order for this test to pass
412        # while tracing with a python function. Tracing used to call
413        # PyFrame_FastToLocals, which would add a copy of any locals to the
414        # frame object, causing the ref count to increase by 2 instead of 1.
415        # While that no longer happens (due to PEP 667), this test case retains
416        # its original global-based implementation
417        # PEP 683's immortal objects also made this point moot, since the
418        # refcount for None doesn't change anyway. Maybe this test should be
419        # using a different constant value? (e.g. an integer)
420        global n
421        self.assertRaises(TypeError, sys.getrefcount)
422        c = sys.getrefcount(None)
423        n = None
424        # Singleton refcnts don't change
425        self.assertEqual(sys.getrefcount(None), c)
426        del n
427        self.assertEqual(sys.getrefcount(None), c)
428        if hasattr(sys, "gettotalrefcount"):
429            self.assertIsInstance(sys.gettotalrefcount(), int)
430
431    def test_getframe(self):
432        self.assertRaises(TypeError, sys._getframe, 42, 42)
433        self.assertRaises(ValueError, sys._getframe, 2000000000)
434        self.assertTrue(
435            SysModuleTest.test_getframe.__code__ \
436            is sys._getframe().f_code
437        )
438
439    def test_getframemodulename(self):
440        # Default depth gets ourselves
441        self.assertEqual(__name__, sys._getframemodulename())
442        self.assertEqual("unittest.case", sys._getframemodulename(1))
443        i = 0
444        f = sys._getframe(i)
445        while f:
446            self.assertEqual(
447                f.f_globals['__name__'],
448                sys._getframemodulename(i) or '__main__'
449            )
450            i += 1
451            f2 = f.f_back
452            try:
453                f = sys._getframe(i)
454            except ValueError:
455                break
456            self.assertIs(f, f2)
457        self.assertIsNone(sys._getframemodulename(i))
458
459    # sys._current_frames() is a CPython-only gimmick.
460    @threading_helper.reap_threads
461    @threading_helper.requires_working_threading()
462    def test_current_frames(self):
463        import threading
464        import traceback
465
466        # Spawn a thread that blocks at a known place.  Then the main
467        # thread does sys._current_frames(), and verifies that the frames
468        # returned make sense.
469        entered_g = threading.Event()
470        leave_g = threading.Event()
471        thread_info = []  # the thread's id
472
473        def f123():
474            g456()
475
476        def g456():
477            thread_info.append(threading.get_ident())
478            entered_g.set()
479            leave_g.wait()
480
481        t = threading.Thread(target=f123)
482        t.start()
483        entered_g.wait()
484
485        try:
486            # At this point, t has finished its entered_g.set(), although it's
487            # impossible to guess whether it's still on that line or has moved on
488            # to its leave_g.wait().
489            self.assertEqual(len(thread_info), 1)
490            thread_id = thread_info[0]
491
492            d = sys._current_frames()
493            for tid in d:
494                self.assertIsInstance(tid, int)
495                self.assertGreater(tid, 0)
496
497            main_id = threading.get_ident()
498            self.assertIn(main_id, d)
499            self.assertIn(thread_id, d)
500
501            # Verify that the captured main-thread frame is _this_ frame.
502            frame = d.pop(main_id)
503            self.assertTrue(frame is sys._getframe())
504
505            # Verify that the captured thread frame is blocked in g456, called
506            # from f123.  This is a little tricky, since various bits of
507            # threading.py are also in the thread's call stack.
508            frame = d.pop(thread_id)
509            stack = traceback.extract_stack(frame)
510            for i, (filename, lineno, funcname, sourceline) in enumerate(stack):
511                if funcname == "f123":
512                    break
513            else:
514                self.fail("didn't find f123() on thread's call stack")
515
516            self.assertEqual(sourceline, "g456()")
517
518            # And the next record must be for g456().
519            filename, lineno, funcname, sourceline = stack[i+1]
520            self.assertEqual(funcname, "g456")
521            self.assertIn(sourceline, ["leave_g.wait()", "entered_g.set()"])
522        finally:
523            # Reap the spawned thread.
524            leave_g.set()
525            t.join()
526
527    @threading_helper.reap_threads
528    @threading_helper.requires_working_threading()
529    def test_current_exceptions(self):
530        import threading
531        import traceback
532
533        # Spawn a thread that blocks at a known place.  Then the main
534        # thread does sys._current_frames(), and verifies that the frames
535        # returned make sense.
536        g_raised = threading.Event()
537        leave_g = threading.Event()
538        thread_info = []  # the thread's id
539
540        def f123():
541            g456()
542
543        def g456():
544            thread_info.append(threading.get_ident())
545            while True:
546                try:
547                    raise ValueError("oops")
548                except ValueError:
549                    g_raised.set()
550                    if leave_g.wait(timeout=support.LONG_TIMEOUT):
551                        break
552
553        t = threading.Thread(target=f123)
554        t.start()
555        g_raised.wait(timeout=support.LONG_TIMEOUT)
556
557        try:
558            self.assertEqual(len(thread_info), 1)
559            thread_id = thread_info[0]
560
561            d = sys._current_exceptions()
562            for tid in d:
563                self.assertIsInstance(tid, int)
564                self.assertGreater(tid, 0)
565
566            main_id = threading.get_ident()
567            self.assertIn(main_id, d)
568            self.assertIn(thread_id, d)
569            self.assertEqual(None, d.pop(main_id))
570
571            # Verify that the captured thread frame is blocked in g456, called
572            # from f123.  This is a little tricky, since various bits of
573            # threading.py are also in the thread's call stack.
574            exc_value = d.pop(thread_id)
575            stack = traceback.extract_stack(exc_value.__traceback__.tb_frame)
576            for i, (filename, lineno, funcname, sourceline) in enumerate(stack):
577                if funcname == "f123":
578                    break
579            else:
580                self.fail("didn't find f123() on thread's call stack")
581
582            self.assertEqual(sourceline, "g456()")
583
584            # And the next record must be for g456().
585            filename, lineno, funcname, sourceline = stack[i+1]
586            self.assertEqual(funcname, "g456")
587            self.assertTrue((sourceline.startswith("if leave_g.wait(") or
588                             sourceline.startswith("g_raised.set()")))
589        finally:
590            # Reap the spawned thread.
591            leave_g.set()
592            t.join()
593
594    def test_attributes(self):
595        self.assertIsInstance(sys.api_version, int)
596        self.assertIsInstance(sys.argv, list)
597        for arg in sys.argv:
598            self.assertIsInstance(arg, str)
599        self.assertIsInstance(sys.orig_argv, list)
600        for arg in sys.orig_argv:
601            self.assertIsInstance(arg, str)
602        self.assertIn(sys.byteorder, ("little", "big"))
603        self.assertIsInstance(sys.builtin_module_names, tuple)
604        self.assertIsInstance(sys.copyright, str)
605        self.assertIsInstance(sys.exec_prefix, str)
606        self.assertIsInstance(sys.base_exec_prefix, str)
607        self.assertIsInstance(sys.executable, str)
608        self.assertEqual(len(sys.float_info), 11)
609        self.assertEqual(sys.float_info.radix, 2)
610        self.assertEqual(len(sys.int_info), 4)
611        self.assertTrue(sys.int_info.bits_per_digit % 5 == 0)
612        self.assertTrue(sys.int_info.sizeof_digit >= 1)
613        self.assertGreaterEqual(sys.int_info.default_max_str_digits, 500)
614        self.assertGreaterEqual(sys.int_info.str_digits_check_threshold, 100)
615        self.assertGreater(sys.int_info.default_max_str_digits,
616                           sys.int_info.str_digits_check_threshold)
617        self.assertEqual(type(sys.int_info.bits_per_digit), int)
618        self.assertEqual(type(sys.int_info.sizeof_digit), int)
619        self.assertIsInstance(sys.int_info.default_max_str_digits, int)
620        self.assertIsInstance(sys.int_info.str_digits_check_threshold, int)
621        self.assertIsInstance(sys.hexversion, int)
622
623        self.assertEqual(len(sys.hash_info), 9)
624        self.assertLess(sys.hash_info.modulus, 2**sys.hash_info.width)
625        # sys.hash_info.modulus should be a prime; we do a quick
626        # probable primality test (doesn't exclude the possibility of
627        # a Carmichael number)
628        for x in range(1, 100):
629            self.assertEqual(
630                pow(x, sys.hash_info.modulus-1, sys.hash_info.modulus),
631                1,
632                "sys.hash_info.modulus {} is a non-prime".format(
633                    sys.hash_info.modulus)
634                )
635        self.assertIsInstance(sys.hash_info.inf, int)
636        self.assertIsInstance(sys.hash_info.nan, int)
637        self.assertIsInstance(sys.hash_info.imag, int)
638        algo = sysconfig.get_config_var("Py_HASH_ALGORITHM")
639        if sys.hash_info.algorithm in {"fnv", "siphash13", "siphash24"}:
640            self.assertIn(sys.hash_info.hash_bits, {32, 64})
641            self.assertIn(sys.hash_info.seed_bits, {32, 64, 128})
642
643            if algo == 1:
644                self.assertEqual(sys.hash_info.algorithm, "siphash24")
645            elif algo == 2:
646                self.assertEqual(sys.hash_info.algorithm, "fnv")
647            elif algo == 3:
648                self.assertEqual(sys.hash_info.algorithm, "siphash13")
649            else:
650                self.assertIn(sys.hash_info.algorithm, {"fnv", "siphash13", "siphash24"})
651        else:
652            # PY_HASH_EXTERNAL
653            self.assertEqual(algo, 0)
654        self.assertGreaterEqual(sys.hash_info.cutoff, 0)
655        self.assertLess(sys.hash_info.cutoff, 8)
656
657        self.assertIsInstance(sys.maxsize, int)
658        self.assertIsInstance(sys.maxunicode, int)
659        self.assertEqual(sys.maxunicode, 0x10FFFF)
660        self.assertIsInstance(sys.platform, str)
661        self.assertIsInstance(sys.prefix, str)
662        self.assertIsInstance(sys.base_prefix, str)
663        self.assertIsInstance(sys.platlibdir, str)
664        self.assertIsInstance(sys.version, str)
665        vi = sys.version_info
666        self.assertIsInstance(vi[:], tuple)
667        self.assertEqual(len(vi), 5)
668        self.assertIsInstance(vi[0], int)
669        self.assertIsInstance(vi[1], int)
670        self.assertIsInstance(vi[2], int)
671        self.assertIn(vi[3], ("alpha", "beta", "candidate", "final"))
672        self.assertIsInstance(vi[4], int)
673        self.assertIsInstance(vi.major, int)
674        self.assertIsInstance(vi.minor, int)
675        self.assertIsInstance(vi.micro, int)
676        self.assertIn(vi.releaselevel, ("alpha", "beta", "candidate", "final"))
677        self.assertIsInstance(vi.serial, int)
678        self.assertEqual(vi[0], vi.major)
679        self.assertEqual(vi[1], vi.minor)
680        self.assertEqual(vi[2], vi.micro)
681        self.assertEqual(vi[3], vi.releaselevel)
682        self.assertEqual(vi[4], vi.serial)
683        self.assertTrue(vi > (1,0,0))
684        self.assertIsInstance(sys.float_repr_style, str)
685        self.assertIn(sys.float_repr_style, ('short', 'legacy'))
686        if not sys.platform.startswith('win'):
687            self.assertIsInstance(sys.abiflags, str)
688
689    def test_thread_info(self):
690        info = sys.thread_info
691        self.assertEqual(len(info), 3)
692        self.assertIn(info.name, ('nt', 'pthread', 'pthread-stubs', 'solaris', None))
693        self.assertIn(info.lock, ('semaphore', 'mutex+cond', None))
694        if sys.platform.startswith(("linux", "android", "freebsd")):
695            self.assertEqual(info.name, "pthread")
696        elif sys.platform == "win32":
697            self.assertEqual(info.name, "nt")
698        elif sys.platform == "emscripten":
699            self.assertIn(info.name, {"pthread", "pthread-stubs"})
700        elif sys.platform == "wasi":
701            self.assertEqual(info.name, "pthread-stubs")
702
703    @unittest.skipUnless(support.is_emscripten, "only available on Emscripten")
704    def test_emscripten_info(self):
705        self.assertEqual(len(sys._emscripten_info), 4)
706        self.assertIsInstance(sys._emscripten_info.emscripten_version, tuple)
707        self.assertIsInstance(sys._emscripten_info.runtime, (str, type(None)))
708        self.assertIsInstance(sys._emscripten_info.pthreads, bool)
709        self.assertIsInstance(sys._emscripten_info.shared_memory, bool)
710
711    def test_43581(self):
712        # Can't use sys.stdout, as this is a StringIO object when
713        # the test runs under regrtest.
714        self.assertEqual(sys.__stdout__.encoding, sys.__stderr__.encoding)
715
716    def test_intern(self):
717        has_is_interned = (test.support.check_impl_detail(cpython=True)
718                           or hasattr(sys, '_is_interned'))
719        self.assertRaises(TypeError, sys.intern)
720        self.assertRaises(TypeError, sys.intern, b'abc')
721        if has_is_interned:
722            self.assertRaises(TypeError, sys._is_interned)
723            self.assertRaises(TypeError, sys._is_interned, b'abc')
724        s = "never interned before" + str(random.randrange(0, 10**9))
725        self.assertTrue(sys.intern(s) is s)
726        if has_is_interned:
727            self.assertIs(sys._is_interned(s), True)
728        s2 = s.swapcase().swapcase()
729        if has_is_interned:
730            self.assertIs(sys._is_interned(s2), False)
731        self.assertTrue(sys.intern(s2) is s)
732        if has_is_interned:
733            self.assertIs(sys._is_interned(s2), False)
734
735        # Subclasses of string can't be interned, because they
736        # provide too much opportunity for insane things to happen.
737        # We don't want them in the interned dict and if they aren't
738        # actually interned, we don't want to create the appearance
739        # that they are by allowing intern() to succeed.
740        class S(str):
741            def __hash__(self):
742                return 123
743
744        self.assertRaises(TypeError, sys.intern, S("abc"))
745        if has_is_interned:
746            self.assertIs(sys._is_interned(S("abc")), False)
747
748    @support.cpython_only
749    @requires_subinterpreters
750    def test_subinterp_intern_dynamically_allocated(self):
751        # Implementation detail: Dynamically allocated strings
752        # are distinct between interpreters
753        s = "never interned before" + str(random.randrange(0, 10**9))
754        t = sys.intern(s)
755        self.assertIs(t, s)
756
757        interp = interpreters.create()
758        interp.exec(textwrap.dedent(f'''
759            import sys
760
761            # set `s`, avoid parser interning & constant folding
762            s = str({s.encode()!r}, 'utf-8')
763
764            t = sys.intern(s)
765
766            assert id(t) != {id(s)}, (id(t), {id(s)})
767            assert id(t) != {id(t)}, (id(t), {id(t)})
768            '''))
769
770    @support.cpython_only
771    @requires_subinterpreters
772    def test_subinterp_intern_statically_allocated(self):
773        # Implementation detail: Statically allocated strings are shared
774        # between interpreters.
775        # See Tools/build/generate_global_objects.py for the list
776        # of strings that are always statically allocated.
777        for s in ('__init__', 'CANCELLED', '<module>', 'utf-8',
778                  '{{', '', '\n', '_', 'x', '\0', '\N{CEDILLA}', '\xff',
779                  ):
780            with self.subTest(s=s):
781                t = sys.intern(s)
782
783                interp = interpreters.create()
784                interp.exec(textwrap.dedent(f'''
785                    import sys
786
787                    # set `s`, avoid parser interning & constant folding
788                    s = str({s.encode()!r}, 'utf-8')
789
790                    t = sys.intern(s)
791                    assert id(t) == {id(t)}, (id(t), {id(t)})
792                    '''))
793
794    @support.cpython_only
795    @requires_subinterpreters
796    def test_subinterp_intern_singleton(self):
797        # Implementation detail: singletons are used for 0- and 1-character
798        # latin1 strings.
799        for s in '', '\n', '_', 'x', '\0', '\N{CEDILLA}', '\xff':
800            with self.subTest(s=s):
801                interp = interpreters.create()
802                interp.exec(textwrap.dedent(f'''
803                    import sys
804
805                    # set `s`, avoid parser interning & constant folding
806                    s = str({s.encode()!r}, 'utf-8')
807
808                    assert id(s) == {id(s)}
809                    t = sys.intern(s)
810                    '''))
811                self.assertTrue(sys._is_interned(s))
812
813    def test_sys_flags(self):
814        self.assertTrue(sys.flags)
815        attrs = ("debug",
816                 "inspect", "interactive", "optimize",
817                 "dont_write_bytecode", "no_user_site", "no_site",
818                 "ignore_environment", "verbose", "bytes_warning", "quiet",
819                 "hash_randomization", "isolated", "dev_mode", "utf8_mode",
820                 "warn_default_encoding", "safe_path", "int_max_str_digits")
821        for attr in attrs:
822            self.assertTrue(hasattr(sys.flags, attr), attr)
823            attr_type = bool if attr in ("dev_mode", "safe_path") else int
824            self.assertEqual(type(getattr(sys.flags, attr)), attr_type, attr)
825        self.assertTrue(repr(sys.flags))
826        self.assertEqual(len(sys.flags), len(attrs))
827
828        self.assertIn(sys.flags.utf8_mode, {0, 1, 2})
829
830    def assert_raise_on_new_sys_type(self, sys_attr):
831        # Users are intentionally prevented from creating new instances of
832        # sys.flags, sys.version_info, and sys.getwindowsversion.
833        arg = sys_attr
834        attr_type = type(sys_attr)
835        with self.assertRaises(TypeError):
836            attr_type(arg)
837        with self.assertRaises(TypeError):
838            attr_type.__new__(attr_type, arg)
839
840    def test_sys_flags_no_instantiation(self):
841        self.assert_raise_on_new_sys_type(sys.flags)
842
843    def test_sys_version_info_no_instantiation(self):
844        self.assert_raise_on_new_sys_type(sys.version_info)
845
846    def test_sys_getwindowsversion_no_instantiation(self):
847        # Skip if not being run on Windows.
848        test.support.get_attribute(sys, "getwindowsversion")
849        self.assert_raise_on_new_sys_type(sys.getwindowsversion())
850
851    @test.support.cpython_only
852    def test_clear_type_cache(self):
853        sys._clear_type_cache()
854
855    @force_not_colorized
856    @support.requires_subprocess()
857    def test_ioencoding(self):
858        env = dict(os.environ)
859
860        # Test character: cent sign, encoded as 0x4A (ASCII J) in CP424,
861        # not representable in ASCII.
862
863        env["PYTHONIOENCODING"] = "cp424"
864        p = subprocess.Popen([sys.executable, "-c", 'print(chr(0xa2))'],
865                             stdout = subprocess.PIPE, env=env)
866        out = p.communicate()[0].strip()
867        expected = ("\xa2" + os.linesep).encode("cp424")
868        self.assertEqual(out, expected)
869
870        env["PYTHONIOENCODING"] = "ascii:replace"
871        p = subprocess.Popen([sys.executable, "-c", 'print(chr(0xa2))'],
872                             stdout = subprocess.PIPE, env=env)
873        out = p.communicate()[0].strip()
874        self.assertEqual(out, b'?')
875
876        env["PYTHONIOENCODING"] = "ascii"
877        p = subprocess.Popen([sys.executable, "-c", 'print(chr(0xa2))'],
878                             stdout=subprocess.PIPE, stderr=subprocess.PIPE,
879                             env=env)
880        out, err = p.communicate()
881        self.assertEqual(out, b'')
882        self.assertIn(b'UnicodeEncodeError:', err)
883        self.assertIn(rb"'\xa2'", err)
884
885        env["PYTHONIOENCODING"] = "ascii:"
886        p = subprocess.Popen([sys.executable, "-c", 'print(chr(0xa2))'],
887                             stdout=subprocess.PIPE, stderr=subprocess.PIPE,
888                             env=env)
889        out, err = p.communicate()
890        self.assertEqual(out, b'')
891        self.assertIn(b'UnicodeEncodeError:', err)
892        self.assertIn(rb"'\xa2'", err)
893
894        env["PYTHONIOENCODING"] = ":surrogateescape"
895        p = subprocess.Popen([sys.executable, "-c", 'print(chr(0xdcbd))'],
896                             stdout=subprocess.PIPE, env=env)
897        out = p.communicate()[0].strip()
898        self.assertEqual(out, b'\xbd')
899
900    @unittest.skipUnless(os_helper.FS_NONASCII,
901                         'requires OS support of non-ASCII encodings')
902    @unittest.skipUnless(sys.getfilesystemencoding() == locale.getpreferredencoding(False),
903                         'requires FS encoding to match locale')
904    @support.requires_subprocess()
905    def test_ioencoding_nonascii(self):
906        env = dict(os.environ)
907
908        env["PYTHONIOENCODING"] = ""
909        p = subprocess.Popen([sys.executable, "-c",
910                                'print(%a)' % os_helper.FS_NONASCII],
911                                stdout=subprocess.PIPE, env=env)
912        out = p.communicate()[0].strip()
913        self.assertEqual(out, os.fsencode(os_helper.FS_NONASCII))
914
915    @unittest.skipIf(sys.base_prefix != sys.prefix,
916                     'Test is not venv-compatible')
917    @support.requires_subprocess()
918    def test_executable(self):
919        # sys.executable should be absolute
920        self.assertEqual(os.path.abspath(sys.executable), sys.executable)
921
922        # Issue #7774: Ensure that sys.executable is an empty string if argv[0]
923        # has been set to a non existent program name and Python is unable to
924        # retrieve the real program name
925
926        # For a normal installation, it should work without 'cwd'
927        # argument. For test runs in the build directory, see #7774.
928        python_dir = os.path.dirname(os.path.realpath(sys.executable))
929        p = subprocess.Popen(
930            ["nonexistent", "-c",
931             'import sys; print(sys.executable.encode("ascii", "backslashreplace"))'],
932            executable=sys.executable, stdout=subprocess.PIPE, cwd=python_dir)
933        stdout = p.communicate()[0]
934        executable = stdout.strip().decode("ASCII")
935        p.wait()
936        self.assertIn(executable, ["b''", repr(sys.executable.encode("ascii", "backslashreplace"))])
937
938    def check_fsencoding(self, fs_encoding, expected=None):
939        self.assertIsNotNone(fs_encoding)
940        codecs.lookup(fs_encoding)
941        if expected:
942            self.assertEqual(fs_encoding, expected)
943
944    def test_getfilesystemencoding(self):
945        fs_encoding = sys.getfilesystemencoding()
946        if sys.platform == 'darwin':
947            expected = 'utf-8'
948        else:
949            expected = None
950        self.check_fsencoding(fs_encoding, expected)
951
952    def c_locale_get_error_handler(self, locale, isolated=False, encoding=None):
953        # Force the POSIX locale
954        env = os.environ.copy()
955        env["LC_ALL"] = locale
956        env["PYTHONCOERCECLOCALE"] = "0"
957        code = '\n'.join((
958            'import sys',
959            'def dump(name):',
960            '    std = getattr(sys, name)',
961            '    print("%s: %s" % (name, std.errors))',
962            'dump("stdin")',
963            'dump("stdout")',
964            'dump("stderr")',
965        ))
966        args = [sys.executable, "-X", "utf8=0", "-c", code]
967        if isolated:
968            args.append("-I")
969        if encoding is not None:
970            env['PYTHONIOENCODING'] = encoding
971        else:
972            env.pop('PYTHONIOENCODING', None)
973        p = subprocess.Popen(args,
974                              stdout=subprocess.PIPE,
975                              stderr=subprocess.STDOUT,
976                              env=env,
977                              universal_newlines=True)
978        stdout, stderr = p.communicate()
979        return stdout
980
981    def check_locale_surrogateescape(self, locale):
982        out = self.c_locale_get_error_handler(locale, isolated=True)
983        self.assertEqual(out,
984                         'stdin: surrogateescape\n'
985                         'stdout: surrogateescape\n'
986                         'stderr: backslashreplace\n')
987
988        # replace the default error handler
989        out = self.c_locale_get_error_handler(locale, encoding=':ignore')
990        self.assertEqual(out,
991                         'stdin: ignore\n'
992                         'stdout: ignore\n'
993                         'stderr: backslashreplace\n')
994
995        # force the encoding
996        out = self.c_locale_get_error_handler(locale, encoding='iso8859-1')
997        self.assertEqual(out,
998                         'stdin: strict\n'
999                         'stdout: strict\n'
1000                         'stderr: backslashreplace\n')
1001        out = self.c_locale_get_error_handler(locale, encoding='iso8859-1:')
1002        self.assertEqual(out,
1003                         'stdin: strict\n'
1004                         'stdout: strict\n'
1005                         'stderr: backslashreplace\n')
1006
1007        # have no any effect
1008        out = self.c_locale_get_error_handler(locale, encoding=':')
1009        self.assertEqual(out,
1010                         'stdin: surrogateescape\n'
1011                         'stdout: surrogateescape\n'
1012                         'stderr: backslashreplace\n')
1013        out = self.c_locale_get_error_handler(locale, encoding='')
1014        self.assertEqual(out,
1015                         'stdin: surrogateescape\n'
1016                         'stdout: surrogateescape\n'
1017                         'stderr: backslashreplace\n')
1018
1019    @support.requires_subprocess()
1020    def test_c_locale_surrogateescape(self):
1021        self.check_locale_surrogateescape('C')
1022
1023    @support.requires_subprocess()
1024    def test_posix_locale_surrogateescape(self):
1025        self.check_locale_surrogateescape('POSIX')
1026
1027    def test_implementation(self):
1028        # This test applies to all implementations equally.
1029
1030        levels = {'alpha': 0xA, 'beta': 0xB, 'candidate': 0xC, 'final': 0xF}
1031
1032        self.assertTrue(hasattr(sys.implementation, 'name'))
1033        self.assertTrue(hasattr(sys.implementation, 'version'))
1034        self.assertTrue(hasattr(sys.implementation, 'hexversion'))
1035        self.assertTrue(hasattr(sys.implementation, 'cache_tag'))
1036
1037        version = sys.implementation.version
1038        self.assertEqual(version[:2], (version.major, version.minor))
1039
1040        hexversion = (version.major << 24 | version.minor << 16 |
1041                      version.micro << 8 | levels[version.releaselevel] << 4 |
1042                      version.serial << 0)
1043        self.assertEqual(sys.implementation.hexversion, hexversion)
1044
1045        # PEP 421 requires that .name be lower case.
1046        self.assertEqual(sys.implementation.name,
1047                         sys.implementation.name.lower())
1048
1049    @test.support.cpython_only
1050    def test_debugmallocstats(self):
1051        # Test sys._debugmallocstats()
1052        from test.support.script_helper import assert_python_ok
1053        args = ['-c', 'import sys; sys._debugmallocstats()']
1054        ret, out, err = assert_python_ok(*args)
1055
1056        # Output of sys._debugmallocstats() depends on configure flags.
1057        # The sysconfig vars are not available on Windows.
1058        if sys.platform != "win32":
1059            with_freelists = sysconfig.get_config_var("WITH_FREELISTS")
1060            with_pymalloc = sysconfig.get_config_var("WITH_PYMALLOC")
1061            if with_freelists:
1062                self.assertIn(b"free PyDictObjects", err)
1063            if with_pymalloc:
1064                self.assertIn(b'Small block threshold', err)
1065            if not with_freelists and not with_pymalloc:
1066                self.assertFalse(err)
1067
1068        # The function has no parameter
1069        self.assertRaises(TypeError, sys._debugmallocstats, True)
1070
1071    @unittest.skipUnless(hasattr(sys, "getallocatedblocks"),
1072                         "sys.getallocatedblocks unavailable on this build")
1073    def test_getallocatedblocks(self):
1074        try:
1075            import _testinternalcapi
1076        except ImportError:
1077            with_pymalloc = support.with_pymalloc()
1078        else:
1079            try:
1080                alloc_name = _testinternalcapi.pymem_getallocatorsname()
1081            except RuntimeError as exc:
1082                # "cannot get allocators name" (ex: tracemalloc is used)
1083                with_pymalloc = True
1084            else:
1085                with_pymalloc = (alloc_name in ('pymalloc', 'pymalloc_debug'))
1086
1087        # Some sanity checks
1088        a = sys.getallocatedblocks()
1089        self.assertIs(type(a), int)
1090        if with_pymalloc:
1091            self.assertGreater(a, 0)
1092        else:
1093            # When WITH_PYMALLOC isn't available, we don't know anything
1094            # about the underlying implementation: the function might
1095            # return 0 or something greater.
1096            self.assertGreaterEqual(a, 0)
1097        try:
1098            # While we could imagine a Python session where the number of
1099            # multiple buffer objects would exceed the sharing of references,
1100            # it is unlikely to happen in a normal test run.
1101            self.assertLess(a, sys.gettotalrefcount())
1102        except AttributeError:
1103            # gettotalrefcount() not available
1104            pass
1105        gc.collect()
1106        b = sys.getallocatedblocks()
1107        self.assertLessEqual(b, a)
1108        gc.collect()
1109        c = sys.getallocatedblocks()
1110        self.assertIn(c, range(b - 50, b + 50))
1111
1112    def test_is_gil_enabled(self):
1113        if support.Py_GIL_DISABLED:
1114            self.assertIs(type(sys._is_gil_enabled()), bool)
1115        else:
1116            self.assertTrue(sys._is_gil_enabled())
1117
1118    def test_is_finalizing(self):
1119        self.assertIs(sys.is_finalizing(), False)
1120        # Don't use the atexit module because _Py_Finalizing is only set
1121        # after calling atexit callbacks
1122        code = """if 1:
1123            import sys
1124
1125            class AtExit:
1126                is_finalizing = sys.is_finalizing
1127                print = print
1128
1129                def __del__(self):
1130                    self.print(self.is_finalizing(), flush=True)
1131
1132            # Keep a reference in the __main__ module namespace, so the
1133            # AtExit destructor will be called at Python exit
1134            ref = AtExit()
1135        """
1136        rc, stdout, stderr = assert_python_ok('-c', code)
1137        self.assertEqual(stdout.rstrip(), b'True')
1138
1139    def test_issue20602(self):
1140        # sys.flags and sys.float_info were wiped during shutdown.
1141        code = """if 1:
1142            import sys
1143            class A:
1144                def __del__(self, sys=sys):
1145                    print(sys.flags)
1146                    print(sys.float_info)
1147            a = A()
1148            """
1149        rc, out, err = assert_python_ok('-c', code)
1150        out = out.splitlines()
1151        self.assertIn(b'sys.flags', out[0])
1152        self.assertIn(b'sys.float_info', out[1])
1153
1154    def test_sys_ignores_cleaning_up_user_data(self):
1155        code = """if 1:
1156            import struct, sys
1157
1158            class C:
1159                def __init__(self):
1160                    self.pack = struct.pack
1161                def __del__(self):
1162                    self.pack('I', -42)
1163
1164            sys.x = C()
1165            """
1166        rc, stdout, stderr = assert_python_ok('-c', code)
1167        self.assertEqual(rc, 0)
1168        self.assertEqual(stdout.rstrip(), b"")
1169        self.assertEqual(stderr.rstrip(), b"")
1170
1171    @unittest.skipUnless(sys.platform == "android", "Android only")
1172    def test_getandroidapilevel(self):
1173        level = sys.getandroidapilevel()
1174        self.assertIsInstance(level, int)
1175        self.assertGreater(level, 0)
1176
1177    @force_not_colorized
1178    @support.requires_subprocess()
1179    def test_sys_tracebacklimit(self):
1180        code = """if 1:
1181            import sys
1182            def f1():
1183                1 / 0
1184            def f2():
1185                f1()
1186            sys.tracebacklimit = %r
1187            f2()
1188        """
1189        def check(tracebacklimit, expected):
1190            p = subprocess.Popen([sys.executable, '-c', code % tracebacklimit],
1191                                 stderr=subprocess.PIPE)
1192            out = p.communicate()[1]
1193            self.assertEqual(out.splitlines(), expected)
1194
1195        traceback = [
1196            b'Traceback (most recent call last):',
1197            b'  File "<string>", line 8, in <module>',
1198            b'    f2()',
1199            b'    ~~^^',
1200            b'  File "<string>", line 6, in f2',
1201            b'    f1()',
1202            b'    ~~^^',
1203            b'  File "<string>", line 4, in f1',
1204            b'    1 / 0',
1205            b'    ~~^~~',
1206            b'ZeroDivisionError: division by zero'
1207        ]
1208        check(10, traceback)
1209        check(3, traceback)
1210        check(2, traceback[:1] + traceback[4:])
1211        check(1, traceback[:1] + traceback[7:])
1212        check(0, [traceback[-1]])
1213        check(-1, [traceback[-1]])
1214        check(1<<1000, traceback)
1215        check(-1<<1000, [traceback[-1]])
1216        check(None, traceback)
1217
1218    def test_no_duplicates_in_meta_path(self):
1219        self.assertEqual(len(sys.meta_path), len(set(sys.meta_path)))
1220
1221    @unittest.skipUnless(hasattr(sys, "_enablelegacywindowsfsencoding"),
1222                         'needs sys._enablelegacywindowsfsencoding()')
1223    def test__enablelegacywindowsfsencoding(self):
1224        code = ('import sys',
1225                'sys._enablelegacywindowsfsencoding()',
1226                'print(sys.getfilesystemencoding(), sys.getfilesystemencodeerrors())')
1227        rc, out, err = assert_python_ok('-c', '; '.join(code))
1228        out = out.decode('ascii', 'replace').rstrip()
1229        self.assertEqual(out, 'mbcs replace')
1230
1231    @support.requires_subprocess()
1232    def test_orig_argv(self):
1233        code = textwrap.dedent('''
1234            import sys
1235            print(sys.argv)
1236            print(sys.orig_argv)
1237        ''')
1238        args = [sys.executable, '-I', '-X', 'utf8', '-c', code, 'arg']
1239        proc = subprocess.run(args, check=True, capture_output=True, text=True)
1240        expected = [
1241            repr(['-c', 'arg']),  # sys.argv
1242            repr(args),  # sys.orig_argv
1243        ]
1244        self.assertEqual(proc.stdout.rstrip().splitlines(), expected,
1245                         proc)
1246
1247    def test_module_names(self):
1248        self.assertIsInstance(sys.stdlib_module_names, frozenset)
1249        for name in sys.stdlib_module_names:
1250            self.assertIsInstance(name, str)
1251
1252    def test_stdlib_dir(self):
1253        os = import_helper.import_fresh_module('os')
1254        marker = getattr(os, '__file__', None)
1255        if marker and not os.path.exists(marker):
1256            marker = None
1257        expected = os.path.dirname(marker) if marker else None
1258        self.assertEqual(os.path.normpath(sys._stdlib_dir),
1259                         os.path.normpath(expected))
1260
1261    @unittest.skipUnless(hasattr(sys, 'getobjects'), 'need sys.getobjects()')
1262    def test_getobjects(self):
1263        # sys.getobjects(0)
1264        all_objects = sys.getobjects(0)
1265        self.assertIsInstance(all_objects, list)
1266        self.assertGreater(len(all_objects), 0)
1267
1268        # sys.getobjects(0, MyType)
1269        class MyType:
1270            pass
1271        size = 100
1272        my_objects = [MyType() for _ in range(size)]
1273        get_objects = sys.getobjects(0, MyType)
1274        self.assertEqual(len(get_objects), size)
1275        for obj in get_objects:
1276            self.assertIsInstance(obj, MyType)
1277
1278        # sys.getobjects(3, MyType)
1279        get_objects = sys.getobjects(3, MyType)
1280        self.assertEqual(len(get_objects), 3)
1281
1282    @unittest.skipUnless(hasattr(sys, '_stats_on'), 'need Py_STATS build')
1283    def test_pystats(self):
1284        # Call the functions, just check that they don't crash
1285        # Cannot save/restore state.
1286        sys._stats_on()
1287        sys._stats_off()
1288        sys._stats_clear()
1289        sys._stats_dump()
1290
1291    @test.support.cpython_only
1292    @unittest.skipUnless(hasattr(sys, 'abiflags'), 'need sys.abiflags')
1293    def test_disable_gil_abi(self):
1294        self.assertEqual('t' in sys.abiflags, support.Py_GIL_DISABLED)
1295
1296
1297@test.support.cpython_only
1298class UnraisableHookTest(unittest.TestCase):
1299    def test_original_unraisablehook(self):
1300        _testcapi = import_helper.import_module('_testcapi')
1301        from _testcapi import err_writeunraisable, err_formatunraisable
1302        obj = hex
1303
1304        with support.swap_attr(sys, 'unraisablehook',
1305                                    sys.__unraisablehook__):
1306            with support.captured_stderr() as stderr:
1307                err_writeunraisable(ValueError(42), obj)
1308            lines = stderr.getvalue().splitlines()
1309            self.assertEqual(lines[0], f'Exception ignored in: {obj!r}')
1310            self.assertEqual(lines[1], 'Traceback (most recent call last):')
1311            self.assertEqual(lines[-1], 'ValueError: 42')
1312
1313            with support.captured_stderr() as stderr:
1314                err_writeunraisable(ValueError(42), None)
1315            lines = stderr.getvalue().splitlines()
1316            self.assertEqual(lines[0], 'Traceback (most recent call last):')
1317            self.assertEqual(lines[-1], 'ValueError: 42')
1318
1319            with support.captured_stderr() as stderr:
1320                err_formatunraisable(ValueError(42), 'Error in %R', obj)
1321            lines = stderr.getvalue().splitlines()
1322            self.assertEqual(lines[0], f'Error in {obj!r}:')
1323            self.assertEqual(lines[1], 'Traceback (most recent call last):')
1324            self.assertEqual(lines[-1], 'ValueError: 42')
1325
1326            with support.captured_stderr() as stderr:
1327                err_formatunraisable(ValueError(42), None)
1328            lines = stderr.getvalue().splitlines()
1329            self.assertEqual(lines[0], 'Traceback (most recent call last):')
1330            self.assertEqual(lines[-1], 'ValueError: 42')
1331
1332    def test_original_unraisablehook_err(self):
1333        # bpo-22836: PyErr_WriteUnraisable() should give sensible reports
1334        class BrokenDel:
1335            def __del__(self):
1336                exc = ValueError("del is broken")
1337                # The following line is included in the traceback report:
1338                raise exc
1339
1340        class BrokenStrException(Exception):
1341            def __str__(self):
1342                raise Exception("str() is broken")
1343
1344        class BrokenExceptionDel:
1345            def __del__(self):
1346                exc = BrokenStrException()
1347                # The following line is included in the traceback report:
1348                raise exc
1349
1350        for test_class in (BrokenDel, BrokenExceptionDel):
1351            with self.subTest(test_class):
1352                obj = test_class()
1353                with test.support.captured_stderr() as stderr, \
1354                     test.support.swap_attr(sys, 'unraisablehook',
1355                                            sys.__unraisablehook__):
1356                    # Trigger obj.__del__()
1357                    del obj
1358
1359                report = stderr.getvalue()
1360                self.assertIn("Exception ignored", report)
1361                self.assertIn(test_class.__del__.__qualname__, report)
1362                self.assertIn("test_sys.py", report)
1363                self.assertIn("raise exc", report)
1364                if test_class is BrokenExceptionDel:
1365                    self.assertIn("BrokenStrException", report)
1366                    self.assertIn("<exception str() failed>", report)
1367                else:
1368                    self.assertIn("ValueError", report)
1369                    self.assertIn("del is broken", report)
1370                self.assertTrue(report.endswith("\n"))
1371
1372    def test_original_unraisablehook_exception_qualname(self):
1373        # See bpo-41031, bpo-45083.
1374        # Check that the exception is printed with its qualified name
1375        # rather than just classname, and the module names appears
1376        # unless it is one of the hard-coded exclusions.
1377        _testcapi = import_helper.import_module('_testcapi')
1378        from _testcapi import err_writeunraisable
1379        class A:
1380            class B:
1381                class X(Exception):
1382                    pass
1383
1384        for moduleName in 'builtins', '__main__', 'some_module':
1385            with self.subTest(moduleName=moduleName):
1386                A.B.X.__module__ = moduleName
1387                with test.support.captured_stderr() as stderr, test.support.swap_attr(
1388                    sys, 'unraisablehook', sys.__unraisablehook__
1389                ):
1390                    err_writeunraisable(A.B.X(), "obj")
1391                report = stderr.getvalue()
1392                self.assertIn(A.B.X.__qualname__, report)
1393                if moduleName in ['builtins', '__main__']:
1394                    self.assertNotIn(moduleName + '.', report)
1395                else:
1396                    self.assertIn(moduleName + '.', report)
1397
1398    def test_original_unraisablehook_wrong_type(self):
1399        exc = ValueError(42)
1400        with test.support.swap_attr(sys, 'unraisablehook',
1401                                    sys.__unraisablehook__):
1402            with self.assertRaises(TypeError):
1403                sys.unraisablehook(exc)
1404
1405    def test_custom_unraisablehook(self):
1406        _testcapi = import_helper.import_module('_testcapi')
1407        from _testcapi import err_writeunraisable, err_formatunraisable
1408        hook_args = None
1409
1410        def hook_func(args):
1411            nonlocal hook_args
1412            hook_args = args
1413
1414        obj = hex
1415        try:
1416            with test.support.swap_attr(sys, 'unraisablehook', hook_func):
1417                exc = ValueError(42)
1418                err_writeunraisable(exc, obj)
1419                self.assertIs(hook_args.exc_type, type(exc))
1420                self.assertIs(hook_args.exc_value, exc)
1421                self.assertIs(hook_args.exc_traceback, exc.__traceback__)
1422                self.assertIsNone(hook_args.err_msg)
1423                self.assertEqual(hook_args.object, obj)
1424
1425                err_formatunraisable(exc, "custom hook %R", obj)
1426                self.assertIs(hook_args.exc_type, type(exc))
1427                self.assertIs(hook_args.exc_value, exc)
1428                self.assertIs(hook_args.exc_traceback, exc.__traceback__)
1429                self.assertEqual(hook_args.err_msg, f'custom hook {obj!r}')
1430                self.assertIsNone(hook_args.object)
1431        finally:
1432            # expected and hook_args contain an exception: break reference cycle
1433            expected = None
1434            hook_args = None
1435
1436    def test_custom_unraisablehook_fail(self):
1437        _testcapi = import_helper.import_module('_testcapi')
1438        from _testcapi import err_writeunraisable
1439        def hook_func(*args):
1440            raise Exception("hook_func failed")
1441
1442        with test.support.captured_output("stderr") as stderr:
1443            with test.support.swap_attr(sys, 'unraisablehook', hook_func):
1444                err_writeunraisable(ValueError(42), "custom hook fail")
1445
1446        err = stderr.getvalue()
1447        self.assertIn(f'Exception ignored in sys.unraisablehook: '
1448                      f'{hook_func!r}\n',
1449                      err)
1450        self.assertIn('Traceback (most recent call last):\n', err)
1451        self.assertIn('Exception: hook_func failed\n', err)
1452
1453
1454@test.support.cpython_only
1455class SizeofTest(unittest.TestCase):
1456
1457    def setUp(self):
1458        self.P = struct.calcsize('P')
1459        self.longdigit = sys.int_info.sizeof_digit
1460        _testinternalcapi = import_helper.import_module("_testinternalcapi")
1461        self.gc_headsize = _testinternalcapi.SIZEOF_PYGC_HEAD
1462        self.managed_pre_header_size = _testinternalcapi.SIZEOF_MANAGED_PRE_HEADER
1463
1464    check_sizeof = test.support.check_sizeof
1465
1466    def test_gc_head_size(self):
1467        # Check that the gc header size is added to objects tracked by the gc.
1468        vsize = test.support.calcvobjsize
1469        gc_header_size = self.gc_headsize
1470        # bool objects are not gc tracked
1471        self.assertEqual(sys.getsizeof(True), vsize('') + self.longdigit)
1472        # but lists are
1473        self.assertEqual(sys.getsizeof([]), vsize('Pn') + gc_header_size)
1474
1475    def test_errors(self):
1476        class BadSizeof:
1477            def __sizeof__(self):
1478                raise ValueError
1479        self.assertRaises(ValueError, sys.getsizeof, BadSizeof())
1480
1481        class InvalidSizeof:
1482            def __sizeof__(self):
1483                return None
1484        self.assertRaises(TypeError, sys.getsizeof, InvalidSizeof())
1485        sentinel = ["sentinel"]
1486        self.assertIs(sys.getsizeof(InvalidSizeof(), sentinel), sentinel)
1487
1488        class FloatSizeof:
1489            def __sizeof__(self):
1490                return 4.5
1491        self.assertRaises(TypeError, sys.getsizeof, FloatSizeof())
1492        self.assertIs(sys.getsizeof(FloatSizeof(), sentinel), sentinel)
1493
1494        class OverflowSizeof(int):
1495            def __sizeof__(self):
1496                return int(self)
1497        self.assertEqual(sys.getsizeof(OverflowSizeof(sys.maxsize)),
1498                         sys.maxsize + self.gc_headsize + self.managed_pre_header_size)
1499        with self.assertRaises(OverflowError):
1500            sys.getsizeof(OverflowSizeof(sys.maxsize + 1))
1501        with self.assertRaises(ValueError):
1502            sys.getsizeof(OverflowSizeof(-1))
1503        with self.assertRaises((ValueError, OverflowError)):
1504            sys.getsizeof(OverflowSizeof(-sys.maxsize - 1))
1505
1506    def test_default(self):
1507        size = test.support.calcvobjsize
1508        self.assertEqual(sys.getsizeof(True), size('') + self.longdigit)
1509        self.assertEqual(sys.getsizeof(True, -1), size('') + self.longdigit)
1510
1511    def test_objecttypes(self):
1512        # check all types defined in Objects/
1513        calcsize = struct.calcsize
1514        size = test.support.calcobjsize
1515        vsize = test.support.calcvobjsize
1516        check = self.check_sizeof
1517        # bool
1518        check(True, vsize('') + self.longdigit)
1519        check(False, vsize('') + self.longdigit)
1520        # buffer
1521        # XXX
1522        # builtin_function_or_method
1523        check(len, size('5P'))
1524        # bytearray
1525        samples = [b'', b'u'*100000]
1526        for sample in samples:
1527            x = bytearray(sample)
1528            check(x, vsize('n2Pi') + x.__alloc__())
1529        # bytearray_iterator
1530        check(iter(bytearray()), size('nP'))
1531        # bytes
1532        check(b'', vsize('n') + 1)
1533        check(b'x' * 10, vsize('n') + 11)
1534        # cell
1535        def get_cell():
1536            x = 42
1537            def inner():
1538                return x
1539            return inner
1540        check(get_cell().__closure__[0], size('P'))
1541        # code
1542        def check_code_size(a, expected_size):
1543            self.assertGreaterEqual(sys.getsizeof(a), expected_size)
1544        check_code_size(get_cell().__code__, size('6i13P'))
1545        check_code_size(get_cell.__code__, size('6i13P'))
1546        def get_cell2(x):
1547            def inner():
1548                return x
1549            return inner
1550        check_code_size(get_cell2.__code__, size('6i13P') + calcsize('n'))
1551        # complex
1552        check(complex(0,1), size('2d'))
1553        # method_descriptor (descriptor object)
1554        check(str.lower, size('3PPP'))
1555        # classmethod_descriptor (descriptor object)
1556        # XXX
1557        # member_descriptor (descriptor object)
1558        import datetime
1559        check(datetime.timedelta.days, size('3PP'))
1560        # getset_descriptor (descriptor object)
1561        import collections
1562        check(collections.defaultdict.default_factory, size('3PP'))
1563        # wrapper_descriptor (descriptor object)
1564        check(int.__add__, size('3P2P'))
1565        # method-wrapper (descriptor object)
1566        check({}.__iter__, size('2P'))
1567        # empty dict
1568        check({}, size('nQ2P'))
1569        # dict (string key)
1570        check({"a": 1}, size('nQ2P') + calcsize(DICT_KEY_STRUCT_FORMAT) + 8 + (8*2//3)*calcsize('2P'))
1571        longdict = {str(i): i for i in range(8)}
1572        check(longdict, size('nQ2P') + calcsize(DICT_KEY_STRUCT_FORMAT) + 16 + (16*2//3)*calcsize('2P'))
1573        # dict (non-string key)
1574        check({1: 1}, size('nQ2P') + calcsize(DICT_KEY_STRUCT_FORMAT) + 8 + (8*2//3)*calcsize('n2P'))
1575        longdict = {1:1, 2:2, 3:3, 4:4, 5:5, 6:6, 7:7, 8:8}
1576        check(longdict, size('nQ2P') + calcsize(DICT_KEY_STRUCT_FORMAT) + 16 + (16*2//3)*calcsize('n2P'))
1577        # dictionary-keyview
1578        check({}.keys(), size('P'))
1579        # dictionary-valueview
1580        check({}.values(), size('P'))
1581        # dictionary-itemview
1582        check({}.items(), size('P'))
1583        # dictionary iterator
1584        check(iter({}), size('P2nPn'))
1585        # dictionary-keyiterator
1586        check(iter({}.keys()), size('P2nPn'))
1587        # dictionary-valueiterator
1588        check(iter({}.values()), size('P2nPn'))
1589        # dictionary-itemiterator
1590        check(iter({}.items()), size('P2nPn'))
1591        # dictproxy
1592        class C(object): pass
1593        check(C.__dict__, size('P'))
1594        # BaseException
1595        check(BaseException(), size('6Pb'))
1596        # UnicodeEncodeError
1597        check(UnicodeEncodeError("", "", 0, 0, ""), size('6Pb 2P2nP'))
1598        # UnicodeDecodeError
1599        check(UnicodeDecodeError("", b"", 0, 0, ""), size('6Pb 2P2nP'))
1600        # UnicodeTranslateError
1601        check(UnicodeTranslateError("", 0, 1, ""), size('6Pb 2P2nP'))
1602        # ellipses
1603        check(Ellipsis, size(''))
1604        # EncodingMap
1605        import codecs, encodings.iso8859_3
1606        x = codecs.charmap_build(encodings.iso8859_3.decoding_table)
1607        check(x, size('32B2iB'))
1608        # enumerate
1609        check(enumerate([]), size('n4P'))
1610        # reverse
1611        check(reversed(''), size('nP'))
1612        # float
1613        check(float(0), size('d'))
1614        # sys.floatinfo
1615        check(sys.float_info, vsize('') + self.P * len(sys.float_info))
1616        # frame
1617        def func():
1618            return sys._getframe()
1619        x = func()
1620        check(x, size('3Pi2c2P7P2ic??2P'))
1621        # function
1622        def func(): pass
1623        check(func, size('15Pi'))
1624        class c():
1625            @staticmethod
1626            def foo():
1627                pass
1628            @classmethod
1629            def bar(cls):
1630                pass
1631            # staticmethod
1632            check(foo, size('PP'))
1633            # classmethod
1634            check(bar, size('PP'))
1635        # generator
1636        def get_gen(): yield 1
1637        check(get_gen(), size('PP4P4c7P2ic??2P'))
1638        # iterator
1639        check(iter('abc'), size('lP'))
1640        # callable-iterator
1641        import re
1642        check(re.finditer('',''), size('2P'))
1643        # list
1644        check(list([]), vsize('Pn'))
1645        check(list([1]), vsize('Pn') + 2*self.P)
1646        check(list([1, 2]), vsize('Pn') + 2*self.P)
1647        check(list([1, 2, 3]), vsize('Pn') + 4*self.P)
1648        # sortwrapper (list)
1649        # XXX
1650        # cmpwrapper (list)
1651        # XXX
1652        # listiterator (list)
1653        check(iter([]), size('lP'))
1654        # listreverseiterator (list)
1655        check(reversed([]), size('nP'))
1656        # int
1657        check(0, vsize('') + self.longdigit)
1658        check(1, vsize('') + self.longdigit)
1659        check(-1, vsize('') + self.longdigit)
1660        PyLong_BASE = 2**sys.int_info.bits_per_digit
1661        check(int(PyLong_BASE), vsize('') + 2*self.longdigit)
1662        check(int(PyLong_BASE**2-1), vsize('') + 2*self.longdigit)
1663        check(int(PyLong_BASE**2), vsize('') + 3*self.longdigit)
1664        # module
1665        if support.Py_GIL_DISABLED:
1666            check(unittest, size('PPPPPP'))
1667        else:
1668            check(unittest, size('PPPPP'))
1669        # None
1670        check(None, size(''))
1671        # NotImplementedType
1672        check(NotImplemented, size(''))
1673        # object
1674        check(object(), size(''))
1675        # property (descriptor object)
1676        class C(object):
1677            def getx(self): return self.__x
1678            def setx(self, value): self.__x = value
1679            def delx(self): del self.__x
1680            x = property(getx, setx, delx, "")
1681            check(x, size('5Pi'))
1682        # PyCapsule
1683        check(_datetime.datetime_CAPI, size('6P'))
1684        # rangeiterator
1685        check(iter(range(1)), size('3l'))
1686        check(iter(range(2**65)), size('3P'))
1687        # reverse
1688        check(reversed(''), size('nP'))
1689        # range
1690        check(range(1), size('4P'))
1691        check(range(66000), size('4P'))
1692        # set
1693        # frozenset
1694        PySet_MINSIZE = 8
1695        samples = [[], range(10), range(50)]
1696        s = size('3nP' + PySet_MINSIZE*'nP' + '2nP')
1697        for sample in samples:
1698            minused = len(sample)
1699            if minused == 0: tmp = 1
1700            # the computation of minused is actually a bit more complicated
1701            # but this suffices for the sizeof test
1702            minused = minused*2
1703            newsize = PySet_MINSIZE
1704            while newsize <= minused:
1705                newsize = newsize << 1
1706            if newsize <= 8:
1707                check(set(sample), s)
1708                check(frozenset(sample), s)
1709            else:
1710                check(set(sample), s + newsize*calcsize('nP'))
1711                check(frozenset(sample), s + newsize*calcsize('nP'))
1712        # setiterator
1713        check(iter(set()), size('P3n'))
1714        # slice
1715        check(slice(0), size('3P'))
1716        # super
1717        check(super(int), size('3P'))
1718        # tuple
1719        check((), vsize(''))
1720        check((1,2,3), vsize('') + 3*self.P)
1721        # type
1722        # static type: PyTypeObject
1723        fmt = 'P2nPI13Pl4Pn9Pn12PIPc'
1724        s = vsize(fmt)
1725        check(int, s)
1726        # class
1727        s = vsize(fmt +                 # PyTypeObject
1728                  '4P'                  # PyAsyncMethods
1729                  '36P'                 # PyNumberMethods
1730                  '3P'                  # PyMappingMethods
1731                  '10P'                 # PySequenceMethods
1732                  '2P'                  # PyBufferProcs
1733                  '6P'
1734                  '1PIP'                 # Specializer cache
1735                  )
1736        class newstyleclass(object): pass
1737        # Separate block for PyDictKeysObject with 8 keys and 5 entries
1738        check(newstyleclass, s + calcsize(DICT_KEY_STRUCT_FORMAT) + 64 + 42*calcsize("2P"))
1739        # dict with shared keys
1740        [newstyleclass() for _ in range(100)]
1741        check(newstyleclass().__dict__, size('nQ2P') + self.P)
1742        o = newstyleclass()
1743        o.a = o.b = o.c = o.d = o.e = o.f = o.g = o.h = 1
1744        # Separate block for PyDictKeysObject with 16 keys and 10 entries
1745        check(newstyleclass, s + calcsize(DICT_KEY_STRUCT_FORMAT) + 64 + 42*calcsize("2P"))
1746        # dict with shared keys
1747        check(newstyleclass().__dict__, size('nQ2P') + self.P)
1748        # unicode
1749        # each tuple contains a string and its expected character size
1750        # don't put any static strings here, as they may contain
1751        # wchar_t or UTF-8 representations
1752        samples = ['1'*100, '\xff'*50,
1753                   '\u0100'*40, '\uffff'*100,
1754                   '\U00010000'*30, '\U0010ffff'*100]
1755        # also update field definitions in test_unicode.test_raiseMemError
1756        asciifields = "nnb"
1757        compactfields = asciifields + "nP"
1758        unicodefields = compactfields + "P"
1759        for s in samples:
1760            maxchar = ord(max(s))
1761            if maxchar < 128:
1762                L = size(asciifields) + len(s) + 1
1763            elif maxchar < 256:
1764                L = size(compactfields) + len(s) + 1
1765            elif maxchar < 65536:
1766                L = size(compactfields) + 2*(len(s) + 1)
1767            else:
1768                L = size(compactfields) + 4*(len(s) + 1)
1769            check(s, L)
1770        # verify that the UTF-8 size is accounted for
1771        s = chr(0x4000)   # 4 bytes canonical representation
1772        check(s, size(compactfields) + 4)
1773        # compile() will trigger the generation of the UTF-8
1774        # representation as a side effect
1775        compile(s, "<stdin>", "eval")
1776        check(s, size(compactfields) + 4 + 4)
1777        # TODO: add check that forces the presence of wchar_t representation
1778        # TODO: add check that forces layout of unicodefields
1779        # weakref
1780        import weakref
1781        if support.Py_GIL_DISABLED:
1782            expected = size('2Pn4P')
1783        else:
1784            expected = size('2Pn3P')
1785        check(weakref.ref(int), expected)
1786        # weakproxy
1787        # XXX
1788        # weakcallableproxy
1789        check(weakref.proxy(int), expected)
1790
1791    def check_slots(self, obj, base, extra):
1792        expected = sys.getsizeof(base) + struct.calcsize(extra)
1793        if gc.is_tracked(obj) and not gc.is_tracked(base):
1794            expected += self.gc_headsize
1795        self.assertEqual(sys.getsizeof(obj), expected)
1796
1797    def test_slots(self):
1798        # check all subclassable types defined in Objects/ that allow
1799        # non-empty __slots__
1800        check = self.check_slots
1801        class BA(bytearray):
1802            __slots__ = 'a', 'b', 'c'
1803        check(BA(), bytearray(), '3P')
1804        class D(dict):
1805            __slots__ = 'a', 'b', 'c'
1806        check(D(x=[]), {'x': []}, '3P')
1807        class L(list):
1808            __slots__ = 'a', 'b', 'c'
1809        check(L(), [], '3P')
1810        class S(set):
1811            __slots__ = 'a', 'b', 'c'
1812        check(S(), set(), '3P')
1813        class FS(frozenset):
1814            __slots__ = 'a', 'b', 'c'
1815        check(FS(), frozenset(), '3P')
1816        from collections import OrderedDict
1817        class OD(OrderedDict):
1818            __slots__ = 'a', 'b', 'c'
1819        check(OD(x=[]), OrderedDict(x=[]), '3P')
1820
1821    def test_pythontypes(self):
1822        # check all types defined in Python/
1823        size = test.support.calcobjsize
1824        vsize = test.support.calcvobjsize
1825        check = self.check_sizeof
1826        # _ast.AST
1827        import _ast
1828        check(_ast.AST(), size('P'))
1829        try:
1830            raise TypeError
1831        except TypeError as e:
1832            tb = e.__traceback__
1833            # traceback
1834            if tb is not None:
1835                check(tb, size('2P2i'))
1836        # symtable entry
1837        # XXX
1838        # sys.flags
1839        # FIXME: The +1 will not be necessary once gh-122575 is fixed
1840        check(sys.flags, vsize('') + self.P * (1 + len(sys.flags)))
1841
1842    def test_asyncgen_hooks(self):
1843        old = sys.get_asyncgen_hooks()
1844        self.assertIsNone(old.firstiter)
1845        self.assertIsNone(old.finalizer)
1846
1847        firstiter = lambda *a: None
1848        finalizer = lambda *a: None
1849
1850        with self.assertRaises(TypeError):
1851            sys.set_asyncgen_hooks(firstiter=firstiter, finalizer="invalid")
1852        cur = sys.get_asyncgen_hooks()
1853        self.assertIsNone(cur.firstiter)
1854        self.assertIsNone(cur.finalizer)
1855
1856        # gh-118473
1857        with self.assertRaises(TypeError):
1858            sys.set_asyncgen_hooks(firstiter="invalid", finalizer=finalizer)
1859        cur = sys.get_asyncgen_hooks()
1860        self.assertIsNone(cur.firstiter)
1861        self.assertIsNone(cur.finalizer)
1862
1863        sys.set_asyncgen_hooks(firstiter=firstiter)
1864        hooks = sys.get_asyncgen_hooks()
1865        self.assertIs(hooks.firstiter, firstiter)
1866        self.assertIs(hooks[0], firstiter)
1867        self.assertIs(hooks.finalizer, None)
1868        self.assertIs(hooks[1], None)
1869
1870        sys.set_asyncgen_hooks(finalizer=finalizer)
1871        hooks = sys.get_asyncgen_hooks()
1872        self.assertIs(hooks.firstiter, firstiter)
1873        self.assertIs(hooks[0], firstiter)
1874        self.assertIs(hooks.finalizer, finalizer)
1875        self.assertIs(hooks[1], finalizer)
1876
1877        sys.set_asyncgen_hooks(*old)
1878        cur = sys.get_asyncgen_hooks()
1879        self.assertIsNone(cur.firstiter)
1880        self.assertIsNone(cur.finalizer)
1881
1882    def test_changing_sys_stderr_and_removing_reference(self):
1883        # If the default displayhook doesn't take a strong reference
1884        # to sys.stderr the following code can crash. See bpo-43660
1885        # for more details.
1886        code = textwrap.dedent('''
1887            import sys
1888            class MyStderr:
1889                def write(self, s):
1890                    sys.stderr = None
1891            sys.stderr = MyStderr()
1892            1/0
1893        ''')
1894        rc, out, err = assert_python_failure('-c', code)
1895        self.assertEqual(out, b"")
1896        self.assertEqual(err, b"")
1897
1898if __name__ == "__main__":
1899    unittest.main()
1900