make polkadot-runtime optional feature (#3820)

* make polkadot-runtime optional feature

* sprinkle some cfg statements

* ok

* ok, ok

* add CI check

* set -e

* chmod +x

* fixes

* fmt

* nicer compile errors

* Update outdated comments

polkadot/node/client/Cargo.toml

@@ -32,7 +32,7 @@ pallet-mmr-primitives = { git = "https://github.com/paritytech/substrate", branc
 beefy-primitives = { git = "https://github.com/paritytech/grandpa-bridge-gadget", branch = "master" }
 
 # Polkadot Runtimes
-polkadot-runtime = { path = "../../runtime/polkadot" }
+polkadot-runtime = { path = "../../runtime/polkadot", optional = true }
 kusama-runtime = { path = "../../runtime/kusama", optional = true }
 westend-runtime = { path = "../../runtime/westend", optional = true }
 rococo-runtime = { path = "../../runtime/rococo", optional = true }
@@ -40,6 +40,8 @@ rococo-runtime = { path = "../../runtime/rococo", optional = true }
 polkadot-primitives = { path = "../../primitives" }
 
 [features]
+default = ["polkadot"]
+polkadot = ["polkadot-runtime"]
 kusama = ["kusama-runtime"]
 rococo = ["rococo-runtime"]
 westend = ["westend-runtime"]

polkadot/node/client/src/lib.rs

@@ -40,9 +40,19 @@ pub type FullBackend = sc_service::TFullBackend<Block>;
 pub type FullClient<RuntimeApi, ExecutorDispatch> =
 	sc_service::TFullClient<Block, RuntimeApi, NativeElseWasmExecutor<ExecutorDispatch>>;
 
+#[cfg(not(any(
+	feature = "rococo",
+	feature = "kusama",
+	feature = "westend",
+	feature = "polkadot"
+)))]
+compile_error!("at least one runtime feature must be enabled");
+
 /// The native executor instance for Polkadot.
+#[cfg(feature = "polkadot")]
 pub struct PolkadotExecutorDispatch;
 
+#[cfg(feature = "polkadot")]
 impl sc_executor::NativeExecutionDispatch for PolkadotExecutorDispatch {
 	type ExtendHostFunctions = frame_benchmarking::benchmarking::HostFunctions;
 
@@ -233,6 +243,7 @@ macro_rules! with_client {
 		}
 	} => {
 		match $self {
+			#[cfg(feature = "polkadot")]
 			Self::Polkadot($client) => { $( $code )* },
 			#[cfg(feature = "westend")]
 			Self::Westend($client) => { $( $code )* },
@@ -249,6 +260,7 @@ macro_rules! with_client {
 /// See [`ExecuteWithClient`] for more information.
 #[derive(Clone)]
 pub enum Client {
+	#[cfg(feature = "polkadot")]
 	Polkadot(Arc<FullClient<polkadot_runtime::RuntimeApi, PolkadotExecutorDispatch>>),
 	#[cfg(feature = "westend")]
 	Westend(Arc<FullClient<westend_runtime::RuntimeApi, WestendExecutorDispatch>>),