investigate flaky parallel/test-trace-atomics-wait

[Trott]

• Version: v15.0-pre (current master branch)
• Platform: macOS 10.15
• Subsystem: test

What steps will reproduce the bug?

https://ci.nodejs.org/job/node-test-commit-osx/36076/nodes=osx1015/console

06:28:40 not ok 2273 parallel/test-trace-atomics-wait
06:28:40   ---
06:28:40   duration_ms: 0.211
06:28:40   severity: fail
06:28:40   exitcode: 1
06:28:40   stack: |-
06:28:40     +++ normalized stdout +++
06:28:40     [Thread 0] Atomics.wait(<address> + 0, 1, inf) started
06:28:40     [Thread 0] Atomics.wait(<address> + 0, 1, inf) did not wait because the values mismatched
06:28:40     [Thread 0] Atomics.wait(<address> + 0, 0, 10) started
06:28:40     [Thread 0] Atomics.wait(<address> + 0, 0, 10) timed out
06:28:40     [Thread 1] Atomics.wait(<address> + 4, -1, inf) started
06:28:40     [Thread 0] Atomics.wait(<address> + 4, 0, inf) started
06:28:40     [Thread 0] Atomics.wait(<address> + 4, 0, inf) did not wait because the values mismatched
06:28:40     [Thread 1] Atomics.wait(<address> + 4, -1, inf) was woken up by another thread
06:28:40     --- normalized stdout ---
06:28:40     assert.js:385
06:28:40         throw err;
06:28:40         ^
06:28:40     
06:28:40     AssertionError [ERR_ASSERTION]: The expression evaluated to a falsy value:
06:28:40     
06:28:40       assert(expectedTimelines.includes(actualTimeline))
06:28:40     
06:28:40         at Object.<anonymous> (/Users/iojs/build/workspace/node-test-commit-osx/nodes/osx1015/test/parallel/test-trace-atomics-wait.js:84:1)
06:28:40         at Module._compile (internal/modules/cjs/loader.js:1090:30)
06:28:40         at Object.Module._extensions..js (internal/modules/cjs/loader.js:1111:10)
06:28:40         at Module.load (internal/modules/cjs/loader.js:955:32)
06:28:40         at Function.Module._load (internal/modules/cjs/loader.js:796:14)
06:28:40         at Function.executeUserEntryPoint [as runMain] (internal/modules/run_main.js:72:12)
06:28:40         at internal/main/run_main_module.js:17:47 {
06:28:40       generatedMessage: true,
06:28:40       code: 'ERR_ASSERTION',
06:28:40       actual: false,
06:28:40       expected: true,
06:28:40       operator: '=='
06:28:40     }
06:28:40   ...

[Trott]

Should the permutation above simply be added to the array of potential valid results? Or is that result a bug? @addaleax

[addaleax]

Yeah, it’s a valid result – #35066 should fix this :)