make mycelium optional

1 files changed, 8 insertions, 1 deletions

diff --git a/src/transport/mod.rs b/src/transport/mod.rs
index 9d43e5a..d8c6e2b 100644
--- a/src/transport/mod.rs
+++ b/src/transport/mod.rs
@@ -18,6 +18,7 @@ pub(crate) mod firewall;
 pub(crate) mod identity;
 #[cfg(feature = "libp2p")]
 pub(crate) mod libp2p;
+#[cfg(feature = "mycelium")]
 pub(crate) mod mycelium;
 pub(crate) mod paths;
 #[cfg(test)]
@@ -28,6 +29,11 @@ pub(crate) mod tor;
 pub(crate) mod traffic;
 pub(crate) mod wire;
 
+#[cfg(not(any(feature = "mycelium", feature = "libp2p", feature = "tor")))]
+compile_error!(
+    "continuum needs a transport: build with at least one of the mycelium, libp2p and tor features, e.g. `cargo build --features mycelium`"
+);
+
 /// Starts the transport `name` (one of `config::TRANSPORTS`) as `settings` configure
 /// it: its scheme and the transport, or None if `stop` came first (some take a while to
 /// start: a supervised Mycelium daemon, arti). `key`: the node key, which some prove
@@ -39,8 +45,9 @@ pub(crate) async fn start(
     stop: tokio::sync::watch::Receiver<bool>,
 ) -> Result<Option<(&'static str, std::sync::Arc<dyn Transport>)>> {
     use std::sync::Arc;
-    let _ = key;
+    let _ = (key, &stop);
     let started: Option<(&'static str, Arc<dyn Transport>)> = match name {
+        #[cfg(feature = "mycelium")]
         "mycelium" => mycelium::start(settings, stop)
             .await?
             .map(|transport| (mycelium::SCHEME, Arc::new(transport) as Arc<dyn Transport>)),