feat(rome_service): configuration file shape

[ematipico]

Summary

This PR closes #2823

I created a new data structure to track the configuration, called Configuration. This object is a separated entity from the WorkspaceSettings because the configuration that we will store in the json file is going to be different.

An example is the enabled field under formatter. Another example will be the extend field, which belongs exclusively to the configuration file.

For this reason, the resolution of the WorkspaceSettings will be done in a different step, where it will be joined with Configuration.

The first shape of the configuration file is the following:

{
  "root": true,
  "formatter": {
    "enabled": true,
    "formatWithErrors": true,
    "indentStyle": "tab",
    "indentSize": 2,
    "lineWidth": 80
  },
  "javascript": {
    "formatter": {
      "quoteStyle": "double"
    }
  }
}

Test Plan

I crated a small test to make sure that ALL fields are correctly mapped and read. Another one to make sure that the default values are correctly initialized by serde.

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[yassere]

I think it's a bit confusing to have line_width be a raw u16 rather than just keeping it as a LineWidth.

If the reason for that is that LineWidth doesn't implement Deserialize, I think you can work around that with something like:

    /// What's the max width of a line. Defaults to 80.
    #[serde(with = "LineWidthDef")]
    pub line_width: LineWidth,
}

#[derive(Deserialize)]
#[serde(remote = "LineWidth")]
pub struct LineWidthDef(pub u16);

[yassere]

If you make the u16 in LineWidth private again (based on the comment from @leops), then I think something like this would still work:

    /// What's the max width of a line. Defaults to 80.
    #[serde(deserialize_with = "deserialize_line_width")]
    pub line_width: LineWidth,
}

fn deserialize_line_width<'de, D>(deserializer: D) -> Result<LineWidth, D::Error>
where
    D: serde::de::Deserializer<'de>,
{
    let value: u16 = Deserialize::deserialize(deserializer)?;
    LineWidth::try_from(value).map_err(serde::de::Error::custom)
}

You'd need to implement Display for LineWidthFromIntError

[ematipico]

Unfortunately doing so will force us to bypass the LineWidth::try_from. This feature requires having a impl From<LineWidthDef> for LineWidth, which goes in conflict with TryFrom

[yassere]

The second snippet I posted wouldn't require a new LineWidthDef struct at all. It's an alternative to the "remote" approach from that first snippet. It seems to work fine when I test it locally.

But I don't think it's a big deal if you want to keep this as line_width: u16
I'll just defer to @leops for this PR since he made this crate.

[leops]

I think the easiest way to deal with this would be to implement Display for LineWidthFromIntError, then we may be able to simply write this:

Suggested change

	pub line_width: u16,
	#[serde(try_from = "u16")]
	pub line_width: LineWidth,

[yassere]

I didn't know about the serde try_from attribute. That's much better!

[ematipico]

unknown serde field attribute `try_from`

Weird?