a test in rust fails only when using tarpaulin

[tessus]

Describe the bug

One of the tests in a rust test suite fails, when tarpaulin is used.

Here's the output for the action: https://github.com/orhun/rustypaste/actions/runs/8196615717/job/22417207146?pr=246#step:5:1

When I run cargo test -- --test-threads 1 locally or remove tarpaulin from the action, all tests pass.

To Reproduce

I don't know how to reproduce this with your own code. I don't know why tarpaulin makes the test fail in the first place.
In the rustypaste project the workflow just has to be triggered and the error happens.

Expected behavior
The test should not fail.

[xd009642]

So I've finally got round to looking at this and I can confirm some tests do fail with the ptrace engine with default args, but using --engine llvm which uses the same backend as cargo-llvm-cov everything passes as expected.

Given ptrace works by intercepting OS signals and rewriting the code to add breakpoints there can be some weird side effects with certain programs especially if signals are used or processes are spawned. I reran the ptrace engine using the flag --follow-exec and all the tests pass with multiple runs so I guess this is down to process spawning somewhere in your code or tests. Using ptrace can be a bit finnicky because you end up needing certain flags sometimes to mitigate certain side effects (and those flags cause different side effects that aren't always desirable)

Sorry I didn't respond earlier had a lot on my plate (and am the sole maintainer 😅 ).

To summarise either run one of these two commands:

cargo tarpaulin --engine llvm
cargo tarpaulin --follow-exec

[tessus]

Thanks a lot for your reply. I'll let orhun know about this. We can try using the options you've suggested.

Have a great weekend.