unit test failure in Core PR 15796

[instagibbs]

make[6]: Entering directory '/home/travis/build/bitcoin/bitcoin/build/bitcoin-x86_64-unknown-linux-gnu/src/secp256k1'
./build-aux/test-driver: line 107: 26441 Aborted                 (core dumped) "$@" > $log_file 2>&1
FAIL: tests
PASS: exhaustive_tests
========================================
   libsecp256k1 0.1: ./test-suite.log
========================================

# TOTAL: 2
# PASS:  1
# SKIP:  0
# XFAIL: 0
# FAIL:  1
# XPASS: 0
# ERROR: 0

.. contents:: :depth: 2

FAIL: tests
===========

src/tests.c:405: test condition failed: ((~x[m][shift]) << (64 - (1 << usebits))) == 0
test count = 64
random seed = 54d904804b5e0db448021441be754c10
FAIL tests (exit status: 134)

============================================================================
Testsuite summary for libsecp256k1 0.1
============================================================================
# TOTAL: 2
# PASS:  1
# SKIP:  0
# XFAIL: 0
# FAIL:  1
# XPASS: 0
# ERROR: 0
============================================================================
See ./test-suite.log
============================================================================
make[6]: *** [test-suite.log] Error 1
Makefile:1213: recipe for target 'test-suite.log' failed
make[6]: Leaving directory '/home/travis/build/bitcoin/bitcoin/build/bitcoin-x86_64-unknown-linux-gnu/src/secp256k1'
make[5]: *** [check-TESTS] Error 2
Makefile:1319: recipe for target 'check-TESTS' failed
make[5]: Leaving directory '/home/travis/build/bitcoin/bitcoin/build/bitcoin-x86_64-unknown-linux-gnu/src/secp256k1'
make[4]: *** [check-am] Error 2
Makefile:1532: recipe for target 'check-am' failed
make[4]: Leaving directory '/home/travis/build/bitcoin/bitcoin/build/bitcoin-x86_64-unknown-linux-gnu/src/secp256k1'
Makefile:13330: recipe for target 'check-local' failed
make[3]: *** [check-local] Error 2
make[3]: Leaving directory '/home/travis/build/bitcoin/bitcoin/build/bitcoin-x86_64-unknown-linux-gnu/src'
make[2]: *** [check-am] Error 2
Makefile:13078: recipe for target 'check-am' failed
make[2]: Leaving directory '/home/travis/build/bitcoin/bitcoin/build/bitcoin-x86_64-unknown-linux-gnu/src'
make[1]: *** [check-recursive] Error 1
Makefile:12766: recipe for target 'check-recursive' failed
make[1]: Leaving directory '/home/travis/build/bitcoin/bitcoin/build/bitcoin-x86_64-unknown-linux-gnu/src'
make: *** [check-recursive] Error 1
Makefile:775: recipe for target 'check-recursive' failed

[instagibbs]

Probably random but felt best to report since I've never seen one in a long time.

[maflcko]

Last time I reproduced them they were non-deterministic even with the same seed used

[sipa]

The randomness tests are known to fail in a small number of cases (there is an old PR about this, #367 but iirc it didn't actually improve things).

@MarcoFalke It should be deterministic if the source code, seed, and test count are identical.

[gmaxwell]

@MarcoFalke Can you clarify what you mean? Unless there is a serious bug there should be no source of nondeterminism in the tests (other than the seed)

[instagibbs]

@MarcoFalke is the seed dumped anywhere?

[sipa]

@instagibbs From your output:

test count = 64
random seed = 54d904804b5e0db448021441be754c10

[jonasnick]

It can be reproduced:

$ ./tests 1 54d904804b5e0db448021441be754c10
test count = 3
random seed = 54d904804b5e0db448021441be754c10
src/tests.c:450: test condition failed: ((~x[m][shift]) << (64 - (1 << usebits))) == 0

[instagibbs]

Good to know, closing unless Marco has a non-reproducible failure with seed