CGOError --> CGOErrCode

[ibeckermayer]

Rather than passing errors via C-strings, we pass them as integers which removes a major potential memory leak/error footgun

(Credit to @zmb3 for this idea)

[strideynet]

I'm not overly familiar with Rust, but the Go/CGo changes look sensible.

Am I right in thinking that with this change we lose some detail on the Go side as to what error actually occurred, but that these errors are now logged in the Rust side ?

[zmb3]

Am I right in thinking that with this change we lose some detail on the Go side as to what error actually occurred, but that these errors are now logged in the Rust side ?

The motivation for this was actually the opposite. We were passing a string from Go to Rust, just so Rust could log the error and then terminate. Now, we log the error on the Go side, and then just indicate to Rust that there was a failure. It's a lot easier to pass an integer than a string across the FFI.

(Though it looks like this was applied in both directions, so you're correct that Rust is also passing only an error code to Go).