Fetching changes proof from remote nodes (#769)

* changes_trie

* changs_trie: continue

* changes_trie: adding tests

* fixed TODO

* removed obsolete ExtrinsicChanges

* encodable ChangesTrieConfiguration

* removed polkadot fle

* fixed grumbles

* ext_storage_changes_root returns u32

* moved changes trie root to digest

* removed commented code

* read storage values from native code

* fixed grumbles

* fixed grumbles

* missing comma

* key changes proof generation + query

* fix grumbles

* check that changes trie config is not changed by block.finalize()

* fixed changes trie config check

substrate/core/test-client/src/client_ext.rs

@@ -38,9 +38,9 @@ pub trait TestClient {
 }
 
 impl<B, E> TestClient for Client<B, E, runtime::Block>
-    where
-        B: client::backend::Backend<runtime::Block, Blake2Hasher>,
-        E: client::CallExecutor<runtime::Block, Blake2Hasher>
+	where
+		B: client::backend::Backend<runtime::Block, Blake2Hasher>,
+		E: client::CallExecutor<runtime::Block, Blake2Hasher>
 {
 	fn justify_and_import(&self, origin: client::BlockOrigin, block: runtime::Block) -> client::error::Result<()> {
 		let authorities: [ed25519::Pair; 3] = [

substrate/core/test-client/src/lib.rs

@@ -68,29 +68,37 @@ pub type Executor = client::LocalCallExecutor<
 
 /// Creates new client instance used for tests.
 pub fn new() -> client::Client<Backend, Executor, runtime::Block> {
-	new_with_backend(Arc::new(Backend::new()))
+	new_with_backend(Arc::new(Backend::new()), false)
+}
+
+/// Creates new test client instance that suports changes trie creation.
+pub fn new_with_changes_trie() -> client::Client<Backend, Executor, runtime::Block> {
+	new_with_backend(Arc::new(Backend::new()), true)
 }
 
 /// Creates new client instance used for tests with an explicitely provided backend.
 /// This is useful for testing backend implementations.
-pub fn new_with_backend<B>(backend: Arc<B>) -> client::Client<B, client::LocalCallExecutor<B, executor::NativeExecutor<LocalExecutor>>, runtime::Block>
+pub fn new_with_backend<B>(
+	backend: Arc<B>,
+	support_changes_trie: bool
+) -> client::Client<B, client::LocalCallExecutor<B, executor::NativeExecutor<LocalExecutor>>, runtime::Block>
 	where
 		B: backend::LocalBackend<runtime::Block, Blake2Hasher>,
 {
 	let executor = NativeExecutor::new();
-	client::new_with_backend(backend, executor, genesis_storage()).unwrap()
+	client::new_with_backend(backend, executor, genesis_storage(support_changes_trie)).unwrap()
 }
 
-fn genesis_config() -> GenesisConfig {
-	GenesisConfig::new_simple(vec![
+fn genesis_config(support_changes_trie: bool) -> GenesisConfig {
+	GenesisConfig::new(support_changes_trie, vec![
 		Keyring::Alice.to_raw_public().into(),
 		Keyring::Bob.to_raw_public().into(),
 		Keyring::Charlie.to_raw_public().into(),
 	], 1000)
 }
 
-fn genesis_storage() -> StorageMap {
-	let mut storage = genesis_config().genesis_map();
+fn genesis_storage(support_changes_trie: bool) -> StorageMap {
+	let mut storage = genesis_config(support_changes_trie).genesis_map();
 	let block: runtime::Block = client::genesis::construct_genesis_block(&storage);
 	storage.extend(additional_storage_with_genesis(&block));
 	storage

substrate/core/test-client/src/trait_tests.rs

@@ -41,7 +41,7 @@ pub fn test_leaves_for_backend<B>(backend: Arc<B>) where
 	//			  B2 -> C3
 	//		A1 -> D2
 
-	let client = ::new_with_backend(backend.clone());
+	let client = ::new_with_backend(backend.clone(), false);
 
 	let genesis_hash = client.info().unwrap().chain.genesis_hash;
 
@@ -153,7 +153,7 @@ pub fn test_blockchain_query_by_number_gets_canonical<B>(backend: Arc<B>) where
 	//		A1 -> B2 -> B3 -> B4
 	//			  B2 -> C3
 	//		A1 -> D2
-	let client = ::new_with_backend(backend);
+	let client = ::new_with_backend(backend, false);
 
 	// G -> A1
 	let a1 = client.new_block().unwrap().bake().unwrap();