Step 10: Register the Ecosystem

Note: this composition root lives in crates/deps-engine/src/setup.rs, not in deps-lsp itself — see The deps-engine crate for why. deps-lsp and deps-cli both call the same deps_engine::setup::register_ecosystems function instead of each maintaining their own registration list, so a new ecosystem crate only needs to be wired in once for both adapters to pick it up.

In crates/deps-engine/src/setup.rs, add your ecosystem using the macros:

#![allow(unused)]
fn main() {
// 1. Add a re-export block using the ecosystem! macro
ecosystem!(
    "{ecosystem_id}",        // Feature flag name (crates/deps-engine/Cargo.toml and
                              // crates/deps-lsp/Cargo.toml/crates/deps-cli/Cargo.toml must
                              // all declare/forward it)
    deps_{ecosystem},        // Crate name
    {Ecosystem}Ecosystem,    // Main ecosystem type
    [
        {Ecosystem}Dependency,
        {Ecosystem}Version,
        {Ecosystem}Registry,
        // ... every other public type this crate exports that a caller of
        // deps_engine might need, e.g. its ParseResult/Formatter/LockParser types
    ]
);

// 2. Add a registration line inside register_ecosystems()
pub fn register_ecosystems(
    registry: &EcosystemRegistry,
    cache: Arc<HttpCache>,
    runtime: &EcosystemRuntime,
) -> Vec<&'static str> {
    // ... existing #[cfg(feature = "...")] blocks for cargo/npm/pypi/go/... ...

    // Add your ecosystem here. Most ecosystems use the plain register! macro:
    #[cfg(feature = "{ecosystem_id}")]
    register!("{ecosystem_id}", {Ecosystem}Ecosystem, registry, &cache);

    // ... existing workspace_registry_ecosystems tracking, if your ecosystem consumes
    // RegistryAccessPolicy (see the EcosystemRuntime note below) ...
}
}

The ecosystem!/register! macros handle feature-gating automatically — when the feature is disabled, both the re-export and the registration are compiled out. Most ecosystems register with the plain register!("{ecosystem_id}", {Ecosystem}Ecosystem, registry, &cache) call shown above; a handful (Cargo, npm, Deno) are special-cased directly in register_ecosystems’s body instead, because they need extra construction-time context (EcosystemRuntime’s RegistryAccessPolicy, an npm/deno shared registry client) that register!’s generic Ecosystem::new(cache) call can’t thread through — only follow one of those special-cased patterns if your ecosystem genuinely needs live-updatable policy or a shared client; otherwise the plain macro call is correct.

If your ecosystem needs to consult registries.workspace_registries (custom/private registry host reachability — see Cargo), push its id onto the Vec<&'static str> this function returns, and thread EcosystemRuntime’s policy field into your parser the same way Cargo’s #[cfg(feature = "cargo")] block does.