refactor(lib): keep the actors inside the crate and mark the growing enums

Every release since 14 has been a major, because the actor mailboxes,
the share index's struct and the CLI's command enum were all exhaustive
public API: adding a peer message, a scanned field or a subcommand read
as a breaking change to the library. The actors, dispatcher, peer
plumbing and download store are how the client is built, not what a host
programs against, so they move inside the crate; PeerMessage, SharedFile
and the CLI command enums are non-exhaustive; ConnectionType is
re-exported at the root for the one thing hosts used it for. A one-time
break so that the next additions are not.

soulseek-rs-lib/src/actor/mod.rs

@@ -52,7 +52,7 @@ impl<M: Send> ActorHandle<M> {
 }
 
 /// Internal actor message wrapper
-pub(crate) enum ActorMessage<M> {
+pub enum ActorMessage<M> {
     UserMessage(M),
     Stop,
 }

soulseek-rs-lib/src/actor/peer_actor.rs

@@ -21,7 +21,9 @@ use std::sync::mpsc::{Receiver, Sender};
 use std::sync::{Arc, RwLock};
 use std::time::{Duration, Instant};
 
+/// Marked non-exhaustive: each peer message the client learns adds a variant.
 #[derive(Debug, Clone)]
+#[non_exhaustive]
 pub enum PeerMessage {
     SendMessage(Message),
     FileSearchResult(SearchResult),

soulseek-rs-lib/src/lib.rs

@@ -2,14 +2,17 @@
 // example in it, so a signature change cannot leave the advertised usage stale.
 #![doc = include_str!("../README.md")]
 
-// Core modules
-pub mod actor;
+// The public surface is the client, its types, the wire codec and the share
+// index. The actors, dispatcher, peer plumbing and download store are how the
+// client is built, not what a host programs against, so they stay inside the
+// crate and a change to them is not a change to the library's API.
+pub(crate) mod actor;
 pub mod client;
-pub mod dispatcher;
-pub mod download_store;
+pub(crate) mod dispatcher;
+pub(crate) mod download_store;
 pub mod error;
 pub mod message;
-pub mod peer;
+pub(crate) mod peer;
 pub mod shares;
 pub mod types;
 #[macro_use]
@@ -31,6 +34,7 @@ pub use actor::server_actor::{PeerAddress, UserMessage};
 pub use client::{Client, ClientSettings};
 pub use error::{Result, SoulseekRs};
 pub use message::peer::{SharedDirectory, SharedFileEntry};
+pub use peer::ConnectionType;
 pub use types::{
     ClientVersion, DownloadStatus, File, RoomEvent, RoomInfo, Search,
     SearchResult, SessionLoss, Transfer, UploadInfo, UploadStatus, UserInfo,

soulseek-rs-lib/src/peer/mod.rs

@@ -3,10 +3,9 @@ pub mod listen;
 pub mod upload_peer;
 
 // Export actor types
-pub use crate::actor::peer_actor::{PeerActor, PeerMessage};
-pub use crate::actor::peer_registry::PeerRegistry;
+pub use crate::actor::peer_actor::PeerMessage;
 
-pub(crate) use download_peer::part_path_of;
+pub use download_peer::part_path_of;
 pub use download_peer::{DownloadError, DownloadPeer};
 
 use crate::message::Message;

soulseek-rs-lib/src/shares/mod.rs

@@ -12,7 +12,11 @@ use std::io;
 use std::path::{Path, PathBuf};
 
 /// One shared file: its peer-facing virtual path and where it lives on disk.
+///
+/// Built by the scan, never by a host, so fields can be added without a
+/// breaking release.
 #[derive(Debug, Clone)]
+#[non_exhaustive]
 pub struct SharedFile {
     /// Backslash-separated path exposed to peers, e.g. `music\album\song.mp3`.
     pub virtual_path: String,

soulseek-rs-lib/tests/e2e.rs

@@ -24,10 +24,9 @@ use std::time::{Duration, Instant};
 
 use soulseek_rs::message::Message;
 use soulseek_rs::message::server::MessageFactory;
-use soulseek_rs::peer::ConnectionType;
 use soulseek_rs::{
-    Client, ClientSettings, ClientVersion, DownloadStatus, PeerAddress,
-    SessionLoss, UploadStatus,
+    Client, ClientSettings, ClientVersion, ConnectionType, DownloadStatus,
+    PeerAddress, SessionLoss, UploadStatus,
 };
 
 /// Only one test at a time may drive a server.

soulseek-rs/src/cli.rs

@@ -172,7 +172,11 @@ pub struct Cli {
     pub log_file: Option<PathBuf>,
 }
 
+/// Non-exhaustive: this enum is public through the crate's library target so
+/// the integration tests can reach it, and a new subcommand must not read as a
+/// breaking change of that library.
 #[derive(Subcommand, Debug)]
+#[non_exhaustive]
 pub enum Commands {
     /// Search the network and print matching files
     Search(SearchArgs),
@@ -254,6 +258,7 @@ pub struct DaemonArgs {
 }
 
 #[derive(Subcommand, Debug)]
+#[non_exhaustive]
 pub enum DaemonCommand {
     /// Print the token remote clients authenticate with
     Token,
@@ -266,6 +271,7 @@ pub enum DaemonCommand {
 }
 
 #[derive(Subcommand, Debug)]
+#[non_exhaustive]
 pub enum CompletionsCommand {
     /// Write the completion script where the shell looks for it
     Install(CompletionsArgs),