Function register_ecosystems 

pub fn register_ecosystems(
    registry: &EcosystemRegistry,
    cache: Arc<HttpCache>,
    runtime: &EcosystemRuntime,
) -> Vec<&'static str>

Registers all enabled ecosystems.

cargo is special-cased (spec #443/#441, plan-1b §1.6): unlike register!’s generic Ecosystem::new(cache) call, CargoEcosystem needs policy threaded through CargoEcosystem::with_context so ServerState’s live-updatable Arc<RegistryAccessPolicy> (see document::state::ServerState::registry_policy) is the exact same handle every Cargo parse reads — initialize/did_change_configuration updating it then takes effect immediately, with no need to reconstruct the ecosystem.

npm and deno are special-cased (#312): when both features are enabled, they share one NpmRegistry instance — built once here and handed to both NpmEcosystem and DenoEcosystem’s npm:-scheme half via with_registry/with_npm — instead of each constructing its own. NpmRegistry is cheaply Clone (its HttpCache and freshness-path publish-time map are both Arc-wrapped internally), so this dedupes the freshness path’s full-packument fetch and its publish-time cache for a package appearing in both package.json and a deno.json npm:-specifier dependency, on top of the plain cached GETs the shared cache already dedupes. Returns every ecosystem id this call threaded the live RegistryAccessPolicy handle into (issue #592 security M1) — the single source of truth config::reparse_scope’s caller consults to scope a registries.workspace_registries reparse, so that set can never drift from what this function actually wires up. Adding a 6th policy-consuming ecosystem means editing this function anyway (to thread policy through its parse context); pushing its id onto the returned list at that same call site keeps the two facts — “receives the policy” and “is in the reparse scope” — physically inseparable, rather than duplicated across two independently-editable places.