api: highlight update for neovim-0-12 and neovim-nightly

[Alexdelia]

solve #311

implement:

• SetHighlightOpts for neovim-0-12 & neovim-nightly
• HighlightCterm for neovim-0-12 & neovim-nightly

also organize & add more test related to highlight

---

first time contributing to this repo, I did not see any guideline, but I ran:

cargo fmt

cargo clippy --features neovim-0-11
cargo clippy --features neovim-0-12
cargo clippy --features neovim-nightly

cargo clippy -p nvim-oxi-api --no-default-features --features neovim-0-11
cargo clippy -p nvim-oxi-api --no-default-features --features neovim-0-12
cargo clippy -p nvim-oxi-api --no-default-features --features neovim-nightly

# with nvim 0.12.2
cargo test -p tests --no-default-features --features neovim-0-12 highlight::

# with nvim 0.11.7
cargo test -p tests --no-default-features --features neovim-0-11 highlight::

# with nvim 0.13.0-nightly
cargo test -p tests --no-default-features --features neovim-nightly highlight::

---

I also tested my fork with my plugin vity.nvim and my nixos/home-manager config https://github.com/Alexdelia/nixconf

[Alexdelia]

my dumb ass didn't check if a PR was already open with this fix

and there is one: #303

sorry about the duplicate

[Alexdelia]

re-open as #303 is not complete

will give it a shot at completing it on this PR

[c-c-k]

Thank you for taking over this issue, I've been putting off finishing my own PR for two months now because I've become obsessed with the idea of using nvim-oxi through an mlua entry point to solve the NVIM crushing on nvim-oxi panics and errors, sorry.

[c-c-k]

@Alexdelia hello, could you please merge the pr/312/Alexdelia/api-highlight-update-for-neovim-0-12-and-neovim-nightly/amend from my fork into your PR.

What it does:

add version feature comments

Adds comments like // Only on 0.11 after each version feature gate.

Rationale: Most of the codebase contains these comments so it would be appropriate to add them here too.

compact neovim-nightly only feature gate to the font field

Removes the separate SetHighlightOpts feature gated struct for neovim-nightly and adds a feature gated font field to the neovim-0-12 struct instead.

Rationale: The C-API change for the SetHighlightOpts struct between NVIM v0.11 and NVIM v0.12 is almost complete so it seems clearer and cleaner to create separate version feature gated structs for each of them.
However, the change between NVIM v0.12 and NVIM v0.13 amounts only to the single font field so I think it would be better to set the feature gate only on the single field.

set HighlightCterm->Dictionary as HighlightCterm->Object->Dictionary

Adds a ToObject implementation for HighlightCterm that uses serde and then changes impl From<HighlightCterm> for Dictionary to convert HighlightCterm to Object and then the Object to a Dictionary.

Rationale: I'm not entirely sure about this one, it would be nice to have @noib3's opinion but I think that the performance drop won't be significant and it would make future maintenance easier.

add OptsBuilder for HighlightCterm

Adds the OptsBuilder derive for HighlightCterm and adjusts the hl_cterm test to use the builder instead of creating HighlightCterm as a Dictionary.

Rationale: I think this better falls in line with the general builder pattern used for creating option arguments.

[Alexdelia]

@Alexdelia hello, could you please merge the pr/312/Alexdelia/api-highlight-update-for-neovim-0-12-and-neovim-nightly/amend from my fork into your PR.

@c-c-k thank you very much for the contribution, the code is much better now

---

I agree with the

c.to_object().unwrap().into_dictionary_unchecked()

this makes the code much easier to understand and maintain

It does add an extra unsafe keyword & .unwrap() to the repo tho

---

I've added your commits to the PR and tested everything just as before

no visible regression on my nvim plugin and nvim config

[c-c-k]

It does add an extra unsafe keyword & .unwrap() to the repo tho

Sorry I was focused on copying builder/serde/conversion logic and didn't think things through, try to replace:

unsafe {
    c.to_object()
        .expect("HighlightCterm.to_object() failed")
        .into_dictionary_unchecked()
}

with:

Self::try_from(
    c.to_object().expect("HighlightCterm.to_object() failed"),
)
.expect("Dictionary::try_from(HighlightCterm.to_object()) failed")

[Alexdelia]

thanks, fixed in bc3838f