Function drop_function

nodedb/src/control/server/pgwire/ddl/function/drop.rs:17–113

Handle `DROP FUNCTION [IF EXISTS] ` Requires superuser or tenant_admin — same privilege level as CREATE FUNCTION.

(
    state: &SharedState,
    identity: &AuthenticatedIdentity,
    parts: &[&str],
)

///
/// Requires superuser or tenant_admin — same privilege level as CREATE FUNCTION.
pub fn drop_function(
    state: &SharedState,
    identity: &AuthenticatedIdentity,
    parts: &[&str],
) -> PgWireResult<Vec<Response>> {
    require_tenant_admin(identity, "drop functions")?;

    let (name, if_exists) = parse_drop_function(parts)?;
    let tenant_id = identity.tenant_id.as_u64();

    let catalog = state
        .credentials
        .catalog()
        .as_ref()
        .ok_or_else(|| sqlstate_error("XX000", "system catalog not available"))?;

    // Check if function exists.
    let func_exists = catalog
        .get_function(tenant_id, &name)
        .map_err(|e| sqlstate_error("XX000", &format!("catalog read: {e}")))?
        .is_some();

    if !func_exists && !if_exists {
        return Err(sqlstate_error(
            "42883",
            &format!("function '{name}' does not exist"),
        ));
    }

    if !func_exists {
        // IF EXISTS and function doesn't exist — no-op.
        return Ok(vec![Response::Execution(Tag::new("DROP FUNCTION"))]);
    }

    // Check dependencies: block DROP if other objects depend on this function.
    let dependents = catalog
        .find_dependents(tenant_id, "function", &name)
        .map_err(|e| sqlstate_error("XX000", &format!("dependency check: {e}")))?;
    if !dependents.is_empty() {
        let dep_list: Vec<String> = dependents
            .iter()
            .map(|(t, n)| format!("{t} '{n}'"))
            .collect();
        return Err(sqlstate_error(
            "2BP01",
            &format!(
                "cannot drop function '{name}': depended on by {}",
                dep_list.join(", ")
            ),
        ));
    }

    // If the function is a WASM function, clean up the stored binary.
    if let Ok(Some(func)) = catalog.get_function(tenant_id, &name)
        && let Some(ref hash) = func.wasm_hash
    {
        let _ = crate::control::planner::wasm::store::delete_wasm_binary(catalog, hash);
    }