Add xdr version to version subcommand output (#293)

cmd/soroban-cli/src/version.rs

@@ -10,7 +10,29 @@ pub struct Cmd;
 impl Cmd {
     #[allow(clippy::unused_self)]
     pub fn run(&self) {
-        println!("soroban {} ({})", env!("CARGO_PKG_VERSION"), GIT_REVISION,);
-        println!("soroban-env-interface-version: {}", meta::INTERFACE_VERSION);
+        println!("soroban {} ({})", env!("CARGO_PKG_VERSION"), GIT_REVISION);
+
+        let env = soroban_env_host::VERSION;
+        println!("soroban-env {} ({})", env.pkg, env.rev);
+        println!("soroban-env interface version {}", meta::INTERFACE_VERSION);
+
+        let xdr = soroban_env_host::VERSION.xdr;
+        println!(
+            "stellar-xdr {} ({})
+xdr next ({})",
+            xdr.pkg, xdr.rev, xdr.xdr_next,
+        );
     }
 }
+
+// Check that the XDR cannel in use is 'next' to ensure that the version output
+// is not forgotten when we eventually update to using curr. This is a bit of a
+// hack because of limits of what you can do in a constant context, but by being
+// a constant context this is checked at compile time.
+const _: () = {
+    #[allow(clippy::single_match)]
+    match soroban_env_host::VERSION.xdr.xdr.as_bytes() {
+        b"next" => (),
+        _ => panic!("xdr version channel needs updating"),
+    }
+};