Code Action Groups

Another general protocol extension poached from rust-analyzer

CodeAction Groups

Client Capability: { "codeActionGroup": boolean }

If this capability is set, CodeAction returned from the server contain an additional field, group:

interface CodeAction {
    title: string;
    group?: string;
    ...
}

All code-actions with the same group should be grouped under single (extendable) entry in lightbulb menu.
The set of actions [ { title: "foo" }, { group: "frobnicate", title: "bar" }, { group: "frobnicate", title: "baz" }] should be rendered as

💡
  +-------------+
  | foo         |
  +-------------+-----+
  | frobnicate >| bar |
  +-------------+-----+
                | baz |
                +-----+

Alternatively, selecting frobnicate could present a user with an additional menu to choose between bar and baz.

Example

fn main() {
    let x: Entry/*cursor here*/ = todo!();
}

Invoking code action at this position will yield two code actions for importing Entry from either collections::HashMap or collection::BTreeMap, grouped under a single "import" group.

Unresolved Questions

• Is a fixed two-level structure enough?
• Should we devise a general way to encode custom interaction protocols for GUI refactorings?

IntelliJ variation:

Start by reading the linked rust-analyzer LSP extension reference and the CodeAction capability/interface described in this issue. Done requires agreement on the grouping structure, client interaction, and protocol behavior; the payload names no repository files or tests.