cargo test sometimes fails with Broken pipe (os error 32) under aarch64

[ereslibre]

Hello!

This bug is not always reproducible, but in my environment happens around ~60% of the runs. One example of the failure:

❯ cargo test -p wasm-tools --all

...

test "tests/cli/semver-check-add-imports.wit"                                  ... ok
test "tests/cli/add-metadata.wat"                                              ... ok
test "tests/cli/world-merging-export-conflict.wit"                             ... ok

failures:

---- "tests/cli/unbundle-print-module1.wat" ----
failed test "tests/cli/unbundle-print-module1.wat"

Caused by:
    Broken pipe (os error 32)


failures:
    "tests/cli/unbundle-print-module1.wat"

test result: FAILED. 105 passed; 1 failed; 0 ignored; 0 measured; 0 filtered out; finished in 0.14s

error: test failed, to rerun pass `-p wasm-tools --test cli`

Sometimes it's this test, sometimes it's others. Another example: NixOS/nixpkgs#341059 (comment)

What all failing tests have in common though, is that they use the tmpdir and pipe feature of the tests.

I can confirm that I could not reproduce the issue after setting --test-threads=1 during the cargo test execution, like:

$ cargo test -p wasm-tools --all -- --test-threads=1

[alexcrichton]

Thanks for the report, and sorry for the breakage! This should be fixed in #1821

[ereslibre]

Oh wow, lightning fast; thanks a ton @alexcrichton!