Handle vyper compiler warnings in asyncExec function

[marcocastignoli]

For some reason Vyper outputs warnings in stderr. With this PR we are handling this case.

[kuzdogan]

Maybe it's better we handle it all in vyperCompiler.ts as we do in the SolidityCompiler?

https://github.com/ethereum/sourcify/blob/0a417e6de521ee23a8e3d19b9192780d36c2ba7e/packages/compilers/src/lib/vyperCompiler.ts#L80-L89

I'm asking because I'm wondering if we throw when we see something in the stdErr, are we going to see these as structured and meaningful errors in a verificationJob? Or just an unstructured string that is coming from the stdErr?

From what I can see it won't because you are checking startsWith which suggests this is a simple string.

Also what happens if there's a Warning in the beginning and errors come later?

[marcocastignoli]

just an unstructured string that is coming from the stdErr

The one I see was just an unstructured string, so I don't think an advanced parsing is needed.

[kuzdogan]

Ok but to my point, when we throw it on the stdErr output, we don't get the structured errors like this one https://verify.sourcify.dev/jobs/65f64b95-2e1b-4a8f-9db3-66985b1c15bd

and also this: "Also what happens if there's a Warning in the beginning and errors come later?"

[marcocastignoli]

Also what happens if there's a Warning in the beginning and errors come later?

Ah! I lost this one, it actually makes sense. Then unfortunately we need to dig deeper into this and create some tests to explore all the cases :(

[kuzdogan]

How about ignoring the stderr and looking for compiler errors in the std JSON output? I wonder if this line of checking stdErr does ever get triggered in Solidity because this asyncExec is a shared function. We need to check how the changes affect both solidity and vyper compilers

[marcocastignoli]

I'll move forward with this by creating some tests with different errors / warnings for both solidity and vyper. Then we'll adapt the fix so that it doesn't break any test.

[marcocastignoli]

I discovered that Vyper < 0.4.0 outputs warnings in the stderr, while vyper >=0.4.0 includes them correctly in the errors object.

@kuzdogan I think the approach of this PR is correct, I added the tests for Vyper to make sure we handle cases (< 0.4.0 AND >= 0.4.0), what do you think?