Short-term fix to make coverage CI check pass

[echeran]

In order to immediately unblock coverage checks, we should remove caching from the coverage checks in CI. (ex: #312)

The longer-term solution is represented separately in #315.

[zbraniecki]

that has been merged now.

[echeran]

The PR to remove caching from the CI coverage checks has been merged. Even though we thought that it would fix the immediate problem, we're currently not seeing the CI coverage checks pass. I want to keep this issue open until we get that working.

[filmil]

Is there a way to run the CI checks locally? That seems to me as a necessary step to get to a place where this can be debugged effectively.

[echeran]

There is nothing official. And there wasn't anything open-source worth trying, at least when I started GH Actions stuff in the summer.. It looks like, in that relatively short time, the leading community tool for this has fixed an important issue recently that makes it worth trying out.

I agree, I don't understand why an important framework wouldn't have a local runner, for exactly that reason.

[zbraniecki]

I got a repro! Manually followed https://github.com/mozilla/grcov#usage until cargo +nightly test reproduced it.

I'm going to try to fix it or switch us to tarpaulin.

[zbraniecki]

Ok, so the issue is described by Alex in rust-lang/cargo#5423

I have two ideas how to fix it:

• Try to run coverage without panic=abort. Not pretty but if it gives us a reasonable coverage, we'll ride it for now and I'll report an issue to grcov.
• Switch to tarpaulin. I have an old PR Switch code coverage to Tarpaulin #184 and I verified that it doesn't require panic=abort.

[zbraniecki]

fixed

[zbraniecki]

Reported upstream as mozilla/grcov#494