Partial derive macro implementation

[arendjr]

I’m starting work on the Partial derive macro, which is supposed to take a struct and generate a companion struct where every field is wrapped in Option (for context, see my original proposal: #1460 (comment)).

Now I’m wondering how opinionated I should make that macro. Given that we are introducing this macro for the purpose of easing the way we implement configuration merging, I think somewhat opinionated makes sense.

For instance, all the structs we apply this too also derive serde’s Serialize and Deserialize. Given that every field will become an Option, I think it only makes sense if the macro inserts the line #[serde(skip_serializing_if = "Option::is_none")] for you. It doesn’t only save us from repetition, it also prevents mistakes, since I already see a few fields where it was forgotten (I don’t think these omissions were intentional).

But what about bpaf? biome_deserialize doesn’t depend on bpaf, so it feels weird if the macro does similar things there, even though it could. But I think it might be useful if it could just insert #[bpaf(hide)] for any fields that don't any other bpaf attributes.

Let me know what you think!

[ematipico]

We shouldn't add bpaf in the macro.

When I added bpaf, documentation was good, but there were still a few hiccups.

Not all the fields of the confirmation should be added to the CLI, and #[bpaf(hide)] doesn't prevent the macro from adding bpaf to the children's fields. I believe it's #[bpaf(pure)].

Anyway, serde makes sense because we must serialise all the fields. Bpaf, not.

[pacak]

#[bpaf(hide)] removes an item from help/autocomplete but if you are parsing it - some value is needed. With #[bpaf(pure)] or pure_with you can specify which value to use instead of trying to parse it.

[Conaclos]

Maybe it is time to create biome_configurationand biome_configuration_macros crates?

[ematipico]

Not a bad idea

[arendjr]

Not a bad idea indeed! I don’t think I need it in the PR I’m currently preparing, but it appears there may be more opportunities for cleanup opening up, especially around config/settings conversions. Those would very much belong there, I imagine. Not sure when I’ll get to that though 😅

[Conaclos]

Implemented.