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GeezerVison is showing github.com — gh-149879: Fix test_math on Cygwin by vstinner · Pull Request #150432 · python/cpython

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vstinner commented May 25, 2026 •

edited by bedevere-app Bot

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Skip tests which fail on Cygwin: when Python is built with newlib C library.

Issue: Enhance Cygwin support #149879

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          pythongh-149879: Fix test_math on Cygwin

cd77dae

Skip tests which fail on Cygwin: when Python is built with newlib C
library.

vstinner added the skip news label

May 25, 2026

bedevere-app Bot added the tests Tests in the Lib/test dir label

May 25, 2026

bedevere-app Bot mentioned this pull request

May 25, 2026

Enhance Cygwin support #149879

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bedevere-app Bot added the awaiting core review label

May 25, 2026

vstinner commented May 25, 2026

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On Cygwin (newlib), 3 functions are not accurate:

math.fma()
math.hypot()
math.log2()

test_math failures (click to unfold):

Details

======================================================================
ERROR: test_fma_infinities (test.test_math.FMATests.test_fma_infinities) (b=-1e+300)
----------------------------------------------------------------------
Traceback (most recent call last):
  File "/home/vstinner/cpython/Lib/test/test_math.py", line 2670, in test_fma_infinities
    self.assertEqual(math.fma(a, b, -math.inf), -math.inf)
                     ~~~~~~~~^^^^^^^^^^^^^^^^^
ValueError: invalid operation in fma

======================================================================
ERROR: test_fma_infinities (test.test_math.FMATests.test_fma_infinities) (b=1e+300)
----------------------------------------------------------------------
Traceback (most recent call last):
  File "/home/vstinner/cpython/Lib/test/test_math.py", line 2669, in test_fma_infinities
    self.assertEqual(math.fma(a, b, math.inf), math.inf)
                     ~~~~~~~~^^^^^^^^^^^^^^^^
ValueError: invalid operation in fma

======================================================================
ERROR: test_fma_infinities (test.test_math.FMATests.test_fma_infinities) (b=-1e+300)
----------------------------------------------------------------------
Traceback (most recent call last):
  File "/home/vstinner/cpython/Lib/test/test_math.py", line 2669, in test_fma_infinities
    self.assertEqual(math.fma(a, b, math.inf), math.inf)
                     ~~~~~~~~^^^^^^^^^^^^^^^^
ValueError: invalid operation in fma

======================================================================
ERROR: test_fma_infinities (test.test_math.FMATests.test_fma_infinities) (b=1e+300)
----------------------------------------------------------------------
Traceback (most recent call last):
  File "/home/vstinner/cpython/Lib/test/test_math.py", line 2670, in test_fma_infinities
    self.assertEqual(math.fma(a, b, -math.inf), -math.inf)
                     ~~~~~~~~^^^^^^^^^^^^^^^^^
ValueError: invalid operation in fma

======================================================================
ERROR: test_fma_overflow (test.test_math.FMATests.test_fma_overflow)
----------------------------------------------------------------------
Traceback (most recent call last):
  File "/home/vstinner/cpython/Lib/test/test_math.py", line 2757, in test_fma_overflow
    self.assertEqual(math.fma(a, b, -c), c)
                     ~~~~~~~~^^^^^^^^^^
OverflowError: overflow in fma

======================================================================
FAIL: test_fma_single_round (test.test_math.FMATests.test_fma_single_round)
----------------------------------------------------------------------
Traceback (most recent call last):
  File "/home/vstinner/cpython/Lib/test/test_math.py", line 2781, in test_fma_single_round
    self.assertEqual(math.fma(a - 1.0, a + 1.0, 1.0), a*a)
    ~~~~~~~~~~~~~~~~^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
AssertionError: 0.0 != 7.888609052210118e-31

======================================================================
FAIL: test_fma_zero_result (test.test_math.FMATests.test_fma_zero_result)
----------------------------------------------------------------------
Traceback (most recent call last):
  File "/home/vstinner/cpython/Lib/test/test_math.py", line 2728, in test_fma_zero_result
    self.assertIsNegativeZero(math.fma(tiny, -tiny, 0.0))
    ~~~~~~~~~~~~~~~~~~~~~~~~~^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/home/vstinner/cpython/Lib/test/test_math.py", line 2846, in assertIsNegativeZero
    self.assertTrue(
    ~~~~~~~~~~~~~~~^
        value == 0 and math.copysign(1, value) < 0,
        ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
        msg="Expected a negative zero, got {!r}".format(value)
        ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
    )
    ^
AssertionError: False is not true : Expected a negative zero, got 0.0

======================================================================
FAIL: test_random (test.test_math.FMATests.test_random) (a_hex='0x1.694adde428b44p-1', b_hex='0x1.371b0d64caed7p-1', c_hex='0x1.f347e7b8deab8p-4', expected_hex='0x1.19f10da56c8adp-1')
----------------------------------------------------------------------
Traceback (most recent call last):
  File "/home/vstinner/cpython/Lib/test/test_math.py", line 2829, in test_random
    self.assertEqual(math.fma(a, b, c), expected)
    ~~~~~~~~~~~~~~~~^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
AssertionError: 0.5506672157701096 != 0.5506672157701097

======================================================================
FAIL: test_random (test.test_math.FMATests.test_random) (a_hex='0x1.605401ccc6ad6p-2', b_hex='0x1.ce3a40bf56640p-2', c_hex='0x1.96e3bf7bf2e20p-2', expected_hex='0x1.1af6d8aa83101p-1')
----------------------------------------------------------------------
Traceback (most recent call last):
  File "/home/vstinner/cpython/Lib/test/test_math.py", line 2829, in test_random
    self.assertEqual(math.fma(a, b, c), expected)
    ~~~~~~~~~~~~~~~~^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
AssertionError: 0.5526645382065283 != 0.5526645382065284

======================================================================
FAIL: test_random (test.test_math.FMATests.test_random) (a_hex='0x1.e5abd653a67d4p-2', b_hex='0x1.a2e400209b3e6p-1', c_hex='0x1.a90051422ce13p-1', expected_hex='0x1.37d68cc8c0fbbp+0')
----------------------------------------------------------------------
Traceback (most recent call last):
  File "/home/vstinner/cpython/Lib/test/test_math.py", line 2829, in test_random
    self.assertEqual(math.fma(a, b, c), expected)
    ~~~~~~~~~~~~~~~~^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
AssertionError: 1.2181175222512897 != 1.2181175222512894

======================================================================
FAIL: test_random (test.test_math.FMATests.test_random) (a_hex='0x1.f94e8efd54700p-2', b_hex='0x1.123065c812cebp-1', c_hex='0x1.458f86fb6ccd0p-1', expected_hex='0x1.ccdcee26a3ff3p-1')
----------------------------------------------------------------------
Traceback (most recent call last):
  File "/home/vstinner/cpython/Lib/test/test_math.py", line 2829, in test_random
    self.assertEqual(math.fma(a, b, c), expected)
    ~~~~~~~~~~~~~~~~^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
AssertionError: 0.9001230642479627 != 0.9001230642479626

======================================================================
FAIL: test_random (test.test_math.FMATests.test_random) (a_hex='0x1.bd926f1eedc96p-1', b_hex='0x1.eee9ca68c5740p-1', c_hex='0x1.960c703eb3298p-2', expected_hex='0x1.3cdcfb4fdb007p+0')
----------------------------------------------------------------------
Traceback (most recent call last):
  File "/home/vstinner/cpython/Lib/test/test_math.py", line 2829, in test_random
    self.assertEqual(math.fma(a, b, c), expected)
    ~~~~~~~~~~~~~~~~^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
AssertionError: 1.2377469129523901 != 1.2377469129523904

======================================================================
FAIL: test_random (test.test_math.FMATests.test_random) (a_hex='0x1.27348350fbccdp-1', b_hex='0x1.3b073914a53f1p-1', c_hex='0x1.e300da5c2b4cbp-1', expected_hex='0x1.4c51e9a3c4e29p+0')
----------------------------------------------------------------------
Traceback (most recent call last):
  File "/home/vstinner/cpython/Lib/test/test_math.py", line 2829, in test_random
    self.assertEqual(math.fma(a, b, c), expected)
    ~~~~~~~~~~~~~~~~^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
AssertionError: 1.2981248879267557 != 1.298124887926756

======================================================================
FAIL: test_random (test.test_math.FMATests.test_random) (a_hex='0x1.2774f00b3497bp-1', b_hex='0x1.7038ec336bff0p-2', c_hex='0x1.2f6f2ccc3576bp-1', expected_hex='0x1.99ad9f9c2688bp-1')
----------------------------------------------------------------------
Traceback (most recent call last):
  File "/home/vstinner/cpython/Lib/test/test_math.py", line 2829, in test_random
    self.assertEqual(math.fma(a, b, c), expected)
    ~~~~~~~~~~~~~~~~^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
AssertionError: 0.8001527670014792 != 0.8001527670014793

======================================================================
FAIL: test_random (test.test_math.FMATests.test_random) (a_hex='0x1.51d5a99300e5cp-1', b_hex='0x1.5cd74abd445a1p-1', c_hex='0x1.8880ab0bbe530p-1', expected_hex='0x1.3756f96b91129p+0')
----------------------------------------------------------------------
Traceback (most recent call last):
  File "/home/vstinner/cpython/Lib/test/test_math.py", line 2829, in test_random
    self.assertEqual(math.fma(a, b, c), expected)
    ~~~~~~~~~~~~~~~~^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
AssertionError: 1.2161708724607458 != 1.2161708724607456

======================================================================
FAIL: test_random (test.test_math.FMATests.test_random) (a_hex='0x1.73cb965b821b8p-2', b_hex='0x1.218fd3d8d5371p-1', c_hex='0x1.d1ea966a1f758p-2', expected_hex='0x1.5217b8fd90119p-1')
----------------------------------------------------------------------
Traceback (most recent call last):
  File "/home/vstinner/cpython/Lib/test/test_math.py", line 2829, in test_random
    self.assertEqual(math.fma(a, b, c), expected)
    ~~~~~~~~~~~~~~~~^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
AssertionError: 0.6603372392201294 != 0.6603372392201293

======================================================================
FAIL: test_random (test.test_math.FMATests.test_random) (a_hex='0x1.4aa98e890b046p-1', b_hex='0x1.954d85dff1041p-1', c_hex='0x1.122b59317ebdfp-1', expected_hex='0x1.0bf644b340cc5p+0')
----------------------------------------------------------------------
Traceback (most recent call last):
  File "/home/vstinner/cpython/Lib/test/test_math.py", line 2829, in test_random
    self.assertEqual(math.fma(a, b, c), expected)
    ~~~~~~~~~~~~~~~~^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
AssertionError: 1.0467265069608387 != 1.0467265069608385

======================================================================
FAIL: test_random (test.test_math.FMATests.test_random) (a_hex='0x1.e28f29e44750fp-1', b_hex='0x1.4bcc4fdcd18fep-1', c_hex='0x1.fd47f81298259p-1', expected_hex='0x1.9b000afbc9995p+0')
----------------------------------------------------------------------
Traceback (most recent call last):
  File "/home/vstinner/cpython/Lib/test/test_math.py", line 2829, in test_random
    self.assertEqual(math.fma(a, b, c), expected)
    ~~~~~~~~~~~~~~~~^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
AssertionError: 1.6054694046702922 != 1.6054694046702924

======================================================================
FAIL: test_random (test.test_math.FMATests.test_random) (a_hex='0x1.d2e850717fe78p-3', b_hex='0x1.1dd7531c303afp-1', c_hex='0x1.e0869746a2fc2p-2', expected_hex='0x1.316df6eb26439p-1')
----------------------------------------------------------------------
Traceback (most recent call last):
  File "/home/vstinner/cpython/Lib/test/test_math.py", line 2829, in test_random
    self.assertEqual(math.fma(a, b, c), expected)
    ~~~~~~~~~~~~~~~~^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
AssertionError: 0.5965420877502146 != 0.5965420877502147

======================================================================
FAIL: test_random (test.test_math.FMATests.test_random) (a_hex='0x1.cf89c75ee6fbap-2', b_hex='0x1.b23decdc66825p-1', c_hex='0x1.3d1fe76ac6168p-1', expected_hex='0x1.00d8ea4c12abbp+0')
----------------------------------------------------------------------
Traceback (most recent call last):
  File "/home/vstinner/cpython/Lib/test/test_math.py", line 2829, in test_random
    self.assertEqual(math.fma(a, b, c), expected)
    ~~~~~~~~~~~~~~~~^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
AssertionError: 1.003309863636487 != 1.0033098636364872

======================================================================
FAIL: test_random (test.test_math.FMATests.test_random) (a_hex='0x1.3265ae6f05572p-2', b_hex='0x1.16d7ec285f7a2p-1', c_hex='0x1.0b8405b3827fbp-1', expected_hex='0x1.5ef33c118a001p-1')
----------------------------------------------------------------------
Traceback (most recent call last):
  File "/home/vstinner/cpython/Lib/test/test_math.py", line 2829, in test_random
    self.assertEqual(math.fma(a, b, c), expected)
    ~~~~~~~~~~~~~~~~^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
AssertionError: 0.6854494830522528 != 0.6854494830522527

======================================================================
FAIL: test_random (test.test_math.FMATests.test_random) (a_hex='0x1.c4d1bf55ec1a5p-1', b_hex='0x1.bc59618459e12p-2', c_hex='0x1.ce5b73dc1773dp-1', expected_hex='0x1.496cf6164f99bp+0')
----------------------------------------------------------------------
Traceback (most recent call last):
  File "/home/vstinner/cpython/Lib/test/test_math.py", line 2829, in test_random
    self.assertEqual(math.fma(a, b, c), expected)
    ~~~~~~~~~~~~~~~~^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
AssertionError: 1.2868188671560348 != 1.286818867156035

======================================================================
FAIL: test_random (test.test_math.FMATests.test_random) (a_hex='0x1.d350026ac3946p-1', b_hex='0x1.9a234e149a68cp-2', c_hex='0x1.f5467b1911fd6p-2', expected_hex='0x1.b5cee3225caa5p-1')
----------------------------------------------------------------------
Traceback (most recent call last):
  File "/home/vstinner/cpython/Lib/test/test_math.py", line 2829, in test_random
    self.assertEqual(math.fma(a, b, c), expected)
    ~~~~~~~~~~~~~~~~^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
AssertionError: 0.8550940494008796 != 0.8550940494008797

======================================================================
FAIL: testHypotAccuracy (test.test_math.MathTests.testHypotAccuracy) (hx='0x1.459c058e20bb7p+30', hy='0x1.993ca009b9178p+29', x=1365705059.531965, y=858231809.2153769)
----------------------------------------------------------------------
Traceback (most recent call last):
  File "/home/vstinner/cpython/Lib/test/test_math.py", line 983, in testHypotAccuracy
    self.assertEqual(hypot(x, y), z)
    ~~~~~~~~~~~~~~~~^^^^^^^^^^^^^^^^
AssertionError: 1612982376.8350067 != 1612982376.8350065

======================================================================
FAIL: testHypotAccuracy (test.test_math.MathTests.testHypotAccuracy) (hx='0x1.378371ae67c0cp+30', hy='0x1.fbe6619854b4cp+29', x=1306582123.6013212, y=1065143347.0413604)
----------------------------------------------------------------------
Traceback (most recent call last):
  File "/home/vstinner/cpython/Lib/test/test_math.py", line 983, in testHypotAccuracy
    self.assertEqual(hypot(x, y), z)
    ~~~~~~~~~~~~~~~~^^^^^^^^^^^^^^^^
AssertionError: 1685730463.467102 != 1685730463.4671018

======================================================================
FAIL: testHypotAccuracy (test.test_math.MathTests.testHypotAccuracy) (hx='0x1.f4cd0574fb97ap+29', hy='0x1.50fe31669340ep+30', x=1050255534.6228478, y=1413450841.6438022)
----------------------------------------------------------------------
Traceback (most recent call last):
  File "/home/vstinner/cpython/Lib/test/test_math.py", line 983, in testHypotAccuracy
    self.assertEqual(hypot(x, y), z)
    ~~~~~~~~~~~~~~~~^^^^^^^^^^^^^^^^
AssertionError: 1760931563.0510736 != 1760931563.0510733

======================================================================
FAIL: testHypotAccuracy (test.test_math.MathTests.testHypotAccuracy) (hx='0x1.f84e649f1e46dp+29', hy='0x1.1fa56bef8eec4p+30', x=1057606803.8897835, y=1206475515.889573)
----------------------------------------------------------------------
Traceback (most recent call last):
  File "/home/vstinner/cpython/Lib/test/test_math.py", line 983, in testHypotAccuracy
    self.assertEqual(hypot(x, y), z)
    ~~~~~~~~~~~~~~~~^^^^^^^^^^^^^^^^
AssertionError: 1604404974.460929 != 1604404974.4609292

======================================================================
FAIL: testHypotAccuracy (test.test_math.MathTests.testHypotAccuracy) (hx='0x1.2e817edd3d6fap+30', hy='0x1.eb0814f1e9602p+29', x=1268801463.3099961, y=1029767838.2389529)
----------------------------------------------------------------------
Traceback (most recent call last):
  File "/home/vstinner/cpython/Lib/test/test_math.py", line 983, in testHypotAccuracy
    self.assertEqual(hypot(x, y), z)
    ~~~~~~~~~~~~~~~~^^^^^^^^^^^^^^^^
AssertionError: 1634098820.135708 != 1634098820.1357083

======================================================================
FAIL: testHypotAccuracy (test.test_math.MathTests.testHypotAccuracy) (hx='0x1.0d3a6e3d04245p+29', hy='0x1.32a62fea52352p+30', x=564612551.6270224, y=1286179834.5802808)
----------------------------------------------------------------------
Traceback (most recent call last):
  File "/home/vstinner/cpython/Lib/test/test_math.py", line 983, in testHypotAccuracy
    self.assertEqual(hypot(x, y), z)
    ~~~~~~~~~~~~~~~~^^^^^^^^^^^^^^^^
AssertionError: 1404651522.739977 != 1404651522.7399766

======================================================================
FAIL: testHypotAccuracy (test.test_math.MathTests.testHypotAccuracy) (hx='0x1.888e19611bfc5p+29', hy='0x1.52b8e70b24353p+29', x=823247660.1386648, y=710352097.3926796)
----------------------------------------------------------------------
Traceback (most recent call last):
  File "/home/vstinner/cpython/Lib/test/test_math.py", line 983, in testHypotAccuracy
    self.assertEqual(hypot(x, y), z)
    ~~~~~~~~~~~~~~~~^^^^^^^^^^^^^^^^
AssertionError: 1087353122.1245313 != 1087353122.124531

======================================================================
FAIL: testHypotAccuracy (test.test_math.MathTests.testHypotAccuracy) (hx='0x1.57b47b7234530p+29', hy='0x1.74e2c7040e772p+29', x=720801646.2755489, y=781998304.5070632)
----------------------------------------------------------------------
Traceback (most recent call last):
  File "/home/vstinner/cpython/Lib/test/test_math.py", line 983, in testHypotAccuracy
    self.assertEqual(hypot(x, y), z)
    ~~~~~~~~~~~~~~~~^^^^^^^^^^^^^^^^
AssertionError: 1063520738.6438042 != 1063520738.6438043

======================================================================
FAIL: testHypotAccuracy (test.test_math.MathTests.testHypotAccuracy) (hx='0x1.94a8d2842a7cfp+30', hy='0x1.326a51d4d8d8ap+30', x=1697264801.0414922, y=1285198965.2117639)
----------------------------------------------------------------------
Traceback (most recent call last):
  File "/home/vstinner/cpython/Lib/test/test_math.py", line 983, in testHypotAccuracy
    self.assertEqual(hypot(x, y), z)
    ~~~~~~~~~~~~~~~~^^^^^^^^^^^^^^^^
AssertionError: 2128953777.1017494 != 2128953777.1017492

======================================================================
FAIL: testHypotAccuracy (test.test_math.MathTests.testHypotAccuracy) (hx='0x1.e930b9cd99035p+29', hy='0x1.5a1030e18dff9p+30', x=1025906489.6997133, y=1451494456.3886702)
----------------------------------------------------------------------
Traceback (most recent call last):
  File "/home/vstinner/cpython/Lib/test/test_math.py", line 983, in testHypotAccuracy
    self.assertEqual(hypot(x, y), z)
    ~~~~~~~~~~~~~~~~^^^^^^^^^^^^^^^^
AssertionError: 1777447687.7070193 != 1777447687.707019

======================================================================
FAIL: testHypotAccuracy (test.test_math.MathTests.testHypotAccuracy) (hx='0x1.5c6bfbec5c4dcp+30', hy='0x1.02511184b4970p+30', x=1461387003.0901403, y=1083458657.1763573)
----------------------------------------------------------------------
Traceback (most recent call last):
  File "/home/vstinner/cpython/Lib/test/test_math.py", line 983, in testHypotAccuracy
    self.assertEqual(hypot(x, y), z)
    ~~~~~~~~~~~~~~~~^^^^^^^^^^^^^^^^
AssertionError: 1819212641.3949463 != 1819212641.394946

======================================================================
FAIL: testHypotAccuracy (test.test_math.MathTests.testHypotAccuracy) (hx='0x1.282bdb82f17f3p+30', hy='0x1.640ba4c4eed3ap+30', x=1242232544.7358367, y=1493362993.2332292)
----------------------------------------------------------------------
Traceback (most recent call last):
  File "/home/vstinner/cpython/Lib/test/test_math.py", line 983, in testHypotAccuracy
    self.assertEqual(hypot(x, y), z)
    ~~~~~~~~~~~~~~~~^^^^^^^^^^^^^^^^
AssertionError: 1942491885.3780012 != 1942491885.3780015

======================================================================
FAIL: testHypotAccuracy (test.test_math.MathTests.testHypotAccuracy) (hx='0x1.89d8c423ea0c6p+29', hy='0x1.d35dcfe902bc3p+29', x=825956484.4892814, y=980138493.1263355)
----------------------------------------------------------------------
Traceback (most recent call last):
  File "/home/vstinner/cpython/Lib/test/test_math.py", line 983, in testHypotAccuracy
    self.assertEqual(hypot(x, y), z)
    ~~~~~~~~~~~~~~~~^^^^^^^^^^^^^^^^
AssertionError: 1281747081.1271062 != 1281747081.127106

======================================================================
FAIL: testLog2 (test.test_math.MathTests.testLog2)
----------------------------------------------------------------------
Traceback (most recent call last):
  File "/home/vstinner/cpython/Lib/test/test_math.py", line 1257, in testLog2
    self.assertEqual(math.log2(2**1023), 1023.0)
    ~~~~~~~~~~~~~~~~^^^^^^^^^^^^^^^^^^^^^^^^^^^^
AssertionError: 1023.0000000000001 != 1023.0

======================================================================
FAIL: testLog2Exact (test.test_math.MathTests.testLog2Exact)
----------------------------------------------------------------------
Traceback (most recent call last):
  File "/home/vstinner/cpython/Lib/test/support/__init__.py", line 405, in wrapper
    return func(*args, **kw)
  File "/home/vstinner/cpython/Lib/test/test_math.py", line 1283, in testLog2Exact
    self.assertEqual(actual, expected)
    ~~~~~~~~~~~~~~~~^^^^^^^^^^^^^^^^^^
AssertionError: Lists differ: [-107[70 chars]066.0000000000002, -1065.0, -1064.0, -1063.0, [21031 chars]0001] != [-107[70 chars]066.0, -1065.0, -1064.0, -1063.0, -1062.0, -10[15515 chars]23.0]

First differing element 8:
-1066.0000000000002
-1066.0

Diff is 32075 characters long. Set self.maxDiff to None to see it.

----------------------------------------------------------------------
Ran 89 tests in 14.300s

FAILED (failures=33, errors=5, skipped=2)

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vstinner commented May 25, 2026

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cc @skirpichev

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vstinner commented May 25, 2026

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Two tests failed on "Windows (free-threading) / Build and test (x64, switch-case)" CI. They are unrelated to this change.

FAIL: test_python_legacy_windows_stdio (test.test_cmd_line.CmdLineTest.test_python_legacy_windows_stdio)
----------------------------------------------------------------------
Traceback (most recent call last):
  File "D:\a\cpython\cpython\Lib\test\test_cmd_line.py", line 1047, in test_python_legacy_windows_stdio
    self.assertEqual(p.returncode, 0)
    ~~~~~~~~~~~~~~~~^^^^^^^^^^^^^^^^^
AssertionError: 3221225794 != 0

See issue gh-150436.


FAIL: test_generator_not_under_consumer_arithmetic (test.test_profiling.test_sampling_profiler.test_blocking.TestBlockingModeStackAccuracy.test_generator_not_under_consumer_arithmetic)
Test that fibonacci_generator doesn't appear when consume_generator does arithmetic.
----------------------------------------------------------------------
Traceback (most recent call last):
  File "D:\a\cpython\cpython\Lib\test\test_profiling\test_sampling_profiler\test_blocking.py", line 137, in test_generator_not_under_consumer_arithmetic
    self.assertEqual(invalid_stacks, 0,
    ~~~~~~~~~~~~~~~~^^^^^^^^^^^^^^^^^^^
        f"Found {invalid_stacks}/{arithmetic_samples} invalid stacks where "
        ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
        f"fibonacci_generator appears in the stack when consume_generator "
        ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
        f"is on an arithmetic line. This indicates torn/inconsistent stack "
        ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
        f"traces are being captured.")
        ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
AssertionError: 652 != 0 : Found 652/4321 invalid stacks where fibonacci_generator appears in the stack when consume_generator is on an arithmetic line. This indicates torn/inconsistent stack traces are being captured.

See issue gh-150429.

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cmaloney approved these changes

May 25, 2026

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          Fix test_statistics

7e743a3

vstinner commented May 26, 2026

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I updated the PR to skip also test_sqrtprod_helper_function_improved_accuracy() of test_statistics.

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skirpichev reviewed

May 26, 2026

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Lib/test/test_math.py Resolved

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Lib/test/test_math.py Resolved

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Lib/test/test_math.py

		# Cases with a 1 ulp error in Python 3.7 compiled with Clang
		('0x1.10e89518dca48p+29', '0x1.1970f7565b7efp+30'),
		('0x1.10106eb4b44a2p+29', '0x1.ef0596cdc97f8p+29'),
		('0x1.459c058e20bb7p+30', '0x1.993ca009b9178p+29'),

skirpichev May 26, 2026

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Now here is 1ulp error, indeed. Though, same looks for all other tests, unless I miss something.

It could be great if you can trace this, maybe it's some case of double rounding, that doesn't catch heuristics in HAVE_DOUBLE_ROUNDING?

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vstinner May 26, 2026

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HAVE_DOUBLE_ROUNDING is False on Cygwin. I don't know how to debug testHypotAccuracy(). It seems easier to me to just skip the test on Cygwin. I don't think that newlib is optmized for accuracy. It's a C library for embedded systems.

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skirpichev May 26, 2026

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HAVE_DOUBLE_ROUNDING is False on Cygwin.

Sure, I understand :-)

I don't know how to debug testHypotAccuracy().

You may compare code flow for given inputs with some "good" platform to see when differences come to play.

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vstinner May 26, 2026

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I will pass that task to the next developer :-)

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Lib/test/test_math.py Resolved

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vstinner added 3 commits

May 26, 2026 04:08


          Move @skip_on_newlib to test.support

a144a7a


          Rename test_random() to test_fma_random()

412dfa9


          unskip testLog2()

9cb8cf5

Move tests on large integer values from testLog2() to
testLog2Exact().

vstinner commented May 26, 2026

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@skirpichev: I updated the PR. Please review the updated PR.

Move @skip_on_newlib to test.support.
Rename test_random() to test_fma_random().
Move tests on large integer values from testLog2() to testLog2Exact().
Unskip testLog2().

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Lib/test/support/__init__.py

Comment on lines +2810 to +2811

		skip_on_newlib = unittest.skipIf(sys.platform == 'cygwin',
		'the test fails on newlib C library')

skirpichev May 26, 2026

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I think you can add support for platform.libc_ver() for newlib and then redo this check. But that's for another pr.

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vstinner May 26, 2026

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Yes. I added @skip_on_newlib instead of using sys.platform == 'cygwin', so later the decorator can be updated at one place if we manage to write a better way to detect newlib C library.

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vstinner enabled auto-merge (squash)

May 26, 2026 02:35

vstinner merged commit b87c991 into python:main

May 26, 2026

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vstinner deleted the test_math branch

May 26, 2026 02:39

bedevere-app Bot removed the awaiting core review label

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vstinner mentioned this pull request

May 26, 2026

gh-85989: move HAVE_DOUBLE_ROUNDING check to test.support #150219

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