protocol: opaque command error

Refactor `CommandError` to be an opaque, boxed error.
Rename it to `Error`, so that it is imported via `command::Error`.

crates/radicle-node/src/runtime/handle.rs

@@ -24,7 +24,7 @@ use crate::profile::Home;
 use crate::reactor;
 use crate::runtime::Emitter;
 use crate::service;
-use crate::service::{CommandError, QueryState};
+use crate::service::QueryState;
 use crate::storage::refs::RefsAt;
 use crate::wire;
 use crate::wire::StreamId;
@@ -38,7 +38,7 @@ pub enum Error {
     ChannelDisconnected,
     /// The command returned an error.
     #[error("command failed: {0}")]
-    Command(#[from] CommandError),
+    Command(#[from] service::command::Error),
     /// The operation timed out.
     #[error("the operation timed out")]
     Timeout,

crates/radicle-protocol/src/service.rs

@@ -3,7 +3,7 @@
 #![allow(clippy::collapsible_if)]
 #![warn(clippy::unwrap_used)]
 pub mod command;
-pub use command::{Command, CommandError, QueryState};
+pub use command::{Command, QueryState};
 
 pub mod filter;
 pub mod gossip;

crates/radicle-protocol/src/service/command.rs

@@ -2,20 +2,18 @@ use std::{collections::HashSet, fmt, sync::Arc, time};
 
 use crossbeam_channel::Sender;
 use radicle::crypto::PublicKey;
-use radicle::node::policy::config as policy;
 use radicle::node::policy::Scope;
-use radicle::node::routing;
 use radicle::node::FetchResult;
 use radicle::node::Seeds;
 use radicle::node::{Address, Alias, Config, ConnectOptions};
-use radicle::storage;
 use radicle::storage::refs::RefsAt;
 use radicle_core::{NodeId, RepoId};
+use thiserror::Error;
 
 use super::ServiceState;
 
 /// Function used to query internal service state.
-pub type QueryState = dyn Fn(&dyn ServiceState) -> Result<(), CommandError> + Send + Sync;
+pub type QueryState = dyn Fn(&dyn ServiceState) -> Result<(), Error> + Send + Sync;
 
 /// Commands sent to the service by the operator.
 pub enum Command {
@@ -47,7 +45,7 @@ pub enum Command {
     /// Unfollow the given node.
     Unfollow(NodeId, Sender<bool>),
     /// Query the internal service state.
-    QueryState(Arc<QueryState>, Sender<Result<(), CommandError>>),
+    QueryState(Arc<QueryState>, Sender<Result<(), Error>>),
 }
 
 impl fmt::Debug for Command {
@@ -71,13 +69,19 @@ impl fmt::Debug for Command {
     }
 }
 
-/// Command-related errors.
-#[derive(thiserror::Error, Debug)]
-pub enum CommandError {
-    #[error(transparent)]
-    Storage(#[from] storage::Error),
-    #[error(transparent)]
-    Routing(#[from] routing::Error),
-    #[error(transparent)]
-    Policy(#[from] policy::Error),
+/// An error that occurred when processing a service [`Command`].
+#[non_exhaustive]
+#[derive(Debug, Error)]
+pub enum Error {
+    #[error("{0}")]
+    Other(#[source] Box<dyn std::error::Error + Send + Sync + 'static>),
+}
+
+impl Error {
+    pub(super) fn other<E>(error: E) -> Self
+    where
+        E: std::error::Error + Send + Sync + 'static,
+    {
+        Self::Other(Box::new(error))
+    }
 }