Error handling

[NYBACHOK]

Problem to solve

Error handling is omitted from tasks. Panic, Result and Option never get mentioned in idioms chapter nor ecosystem.

Proposal

Add task to 3_ecosystem where it would be required to refactor library code from manual mapping errors to usage of thiserror + write tests with usage of anyhow.

Prior art

https://doc.rust-lang.org/book/ch09-01-unrecoverable-errors-with-panic.html#unrecoverable-errors-with-panic

Alternatives

Error handling mentioned in 5_zero2prod.

Links & references

https://doc.rust-lang.org/book/ch09-01-unrecoverable-errors-with-panic.html#unrecoverable-errors-with-panic

https://docs.rs/thiserror/latest/thiserror/

https://docs.rs/anyhow/latest/anyhow/

[NamesMark]

Agree! I could've sworn it was mentioned, but you are right, it's not here :)

There's multiple levels of error handling and it would be nice to explain this progression from "lazy and fast" to "proper and structured"

Result<(), ()> -> Result<(), String> -> Result<(), CustomError>
anyhow/eyre -> thiserror

[NYBACHOK]

Well. This topic may be expanted panic recomendation too

[NamesMark]

The problem I see is that module 3 is already quite heavy. Maybe we can add it to the end of module 2, as it's kinda also a part of the "idioms", and the error crates can be considered secondary to this topic?

[kilterdev]

The problem I see is that module 3 is already quite heavy. Maybe we can add it to the end of module 2, as it's kinda also a part of the "idioms", and the error crates can be considered secondary to this topic?

Could not agree more on this. I support the idea of ​​pushing this topic straight in to the pile of the (2)nd chapter.
It really feels more natural being in this category, after all the approach of proper error handling is at the very core of being idiomatic (in the context of Rust)...

Also it's a bit strange such an important subject was not covered on the early stage, where it truly belongs. Tho, i believe there were reasons for it.