prepend signal number and thread ID on backtraces

[d-netto]

These extra information on the backtraces proved useful for us when filtering which servers failed due to a segmentation fault, for instance, and when diagnosing crashes in production more in general.

[vchuravy]

Can you show some examples where this is useful and how the format ended up? Would it be possible to add tests?

[kpamnany]

This is how we're currently solving https://github.com/JuliaLang/julia/issues/51056. You can see what it looks like in https://github.com/JuliaLang/julia/issues/51659.

The thread ID prefix is simply to help disambiguate stack traces if they're reported concurrently. It is not informational, i.e. it isn't intended to be the thread ID on which the stack trace was gathered (which is not especially useful information anyway).

Jameson suggested using the task pointer instead but I feel that is even less useful.

[kpamnany]

not especially useful information anyway).

Now that I think about it, it would be useful information. We'll look into https://github.com/JuliaLang/julia/pull/41742, thanks for the pointer!