rpc: add rpc v2 chainSpec to polkadot (paritytech#2859)

The [chainSpec RPC API from the v2
spec](https://paritytech.github.io/json-rpc-interface-spec/api/chainSpec.html)
was only added to substrate-node and should be added to polkadot as well

/cc @lexnv

substrate/bin/node-template/node/src/rpc.rs

@@ -53,5 +53,12 @@ where
 	// to call into the runtime.
 	// `module.merge(YourRpcTrait::into_rpc(YourRpcStruct::new(ReferenceToClient, ...)))?;`
 
+	// You probably want to enable the `rpc v2 chainSpec` API as well
+	//
+	// let chain_name = chain_spec.name().to_string();
+	// let genesis_hash = client.block_hash(0).ok().flatten().expect("Genesis block exists; qed");
+	// let properties = chain_spec.properties();
+	// module.merge(ChainSpec::new(chain_name, genesis_hash, properties).into_rpc())?;
+
 	Ok(module)
 }

substrate/client/consensus/beefy/src/import.rs

@@ -148,7 +148,7 @@ where
 				// The block is imported as part of some chain sync.
 				// The voter doesn't need to process it now.
 				// It will be detected and processed as part of the voter state init.
-				return Ok(inner_import_result);
+				return Ok(inner_import_result)
 			},
 		}
 

substrate/client/consensus/beefy/src/lib.rs

@@ -398,7 +398,7 @@ where
 			header =
 				wait_for_parent_header(backend.blockchain(), header, HEADER_SYNC_DELAY).await?;
 		}
-		return Ok(state);
+		return Ok(state)
 	}
 
 	// No valid voter-state persisted, re-initialize from pallet genesis.

substrate/client/network/src/protocol/notifications/behaviour.rs

@@ -1037,7 +1037,7 @@ impl Notifications {
 						peerset_rejected,
 						incoming_index,
 					};
-					return self.report_reject(index).map_or((), |_| ());
+					return self.report_reject(index).map_or((), |_| ())
 				}
 
 				trace!(

substrate/frame/contracts/fixtures/build.rs

@@ -105,7 +105,7 @@ fn collect_entries(contracts_dir: &Path, out_dir: &Path) -> Vec<Entry> {
 		.filter_map(|file| {
 			let path = file.expect("file exists; qed").path();
 			if path.extension().map_or(true, |ext| ext != "rs") {
-				return None;
+				return None
 			}
 
 			let entry = Entry::new(path);
@@ -307,7 +307,7 @@ fn find_workspace_root(current_dir: &Path) -> Option<PathBuf> {
 			let cargo_toml_contents =
 				std::fs::read_to_string(current_dir.join("Cargo.toml")).ok()?;
 			if cargo_toml_contents.contains("[workspace]") {
-				return Some(current_dir);
+				return Some(current_dir)
 			}
 		}
 
@@ -325,7 +325,7 @@ fn main() -> Result<()> {
 
 	let entries = collect_entries(&contracts_dir, &out_dir);
 	if entries.is_empty() {
-		return Ok(());
+		return Ok(())
 	}
 
 	let tmp_dir = tempfile::tempdir()?;

substrate/frame/support/procedural/src/construct_runtime/expand/task.rs

@@ -31,7 +31,7 @@ pub fn expand_outer_task(
 	let mut task_paths = Vec::new();
 	for decl in pallet_decls {
 		if decl.find_part("Task").is_none() {
-			continue;
+			continue
 		}
 
 		let variant_name = &decl.name;

substrate/frame/system/src/tests.rs

@@ -828,7 +828,7 @@ fn last_runtime_upgrade_spec_version_usage() {
 			// a runtime upgrade in the pipeline of being applied, you should use the spec version
 			// of this upgrade.
 			if System::last_runtime_upgrade_spec_version() > 1337 {
-				return Weight::zero();
+				return Weight::zero()
 			}
 
 			// Do the migration.

substrate/primitives/core/src/address_uri.rs

@@ -184,7 +184,7 @@ impl<'a> AddressUri<'a> {
 					Error::in_pass(initial_input, initial_input_len - input.len())
 				} else {
 					Error::in_phrase(initial_input, initial_input_len - input.len())
-				});
+				})
 			}
 		}
 

substrate/primitives/core/src/crypto.rs

@@ -434,7 +434,7 @@ impl<T: Sized + AsMut<[u8]> + AsRef<[u8]> + Public + Derive> Ss58Codec for T {
 	fn from_string(s: &str) -> Result<Self, PublicError> {
 		let cap = AddressUri::parse(s)?;
 		if cap.pass.is_some() {
-			return Err(PublicError::PasswordNotAllowed);
+			return Err(PublicError::PasswordNotAllowed)
 		}
 		let s = cap.phrase.unwrap_or(DEV_ADDRESS);
 		let addr = if let Some(stripped) = s.strip_prefix("0x") {
@@ -454,7 +454,7 @@ impl<T: Sized + AsMut<[u8]> + AsRef<[u8]> + Public + Derive> Ss58Codec for T {
 	fn from_string_with_version(s: &str) -> Result<(Self, Ss58AddressFormat), PublicError> {
 		let cap = AddressUri::parse(s)?;
 		if cap.pass.is_some() {
-			return Err(PublicError::PasswordNotAllowed);
+			return Err(PublicError::PasswordNotAllowed)
 		}
 		let (addr, v) = Self::from_ss58check_with_version(cap.phrase.unwrap_or(DEV_ADDRESS))?;
 		if cap.paths.is_empty() {

substrate/utils/wasm-builder/src/wasm_project.rs

@@ -935,7 +935,7 @@ fn generate_rerun_if_changed_instructions(
 	while let Some(dependency) = dependencies.pop() {
 		// Ignore all dev dependencies
 		if dependency.kind == DependencyKind::Development {
-			continue;
+			continue
 		}
 
 		let path_or_git_dep =