Fix key collision for child trie (#4162)

* In progress, runtime io must switch to future proof root +
child_specific (unique id) + u32 type.

* Switch interface, sr-io seems ok, rpc could use similar interface to
sr-io, genesis json broken if there is child trie in existing encoding
genesis.

* test from previous implementation.

* fix proving test.

* Restore Keyspacedb from other branch, only apply to child trie.

* Removing unneeded child_info from child root (child info are stored
if things changed, otherwhise the root does not change).

* Switch rpc to use same format as ext: more future proof.

* use root from child info for trie backend essence.

* Breaking long lines.

* Update doc and clean pr a bit.

* fix error type

* Restore removed doc on merge and update sr-io doc.

* Switch child storage api to use directly unique id, if managed id
where to be put in place, the api will change at this time.

* Clean deprecated host interface from child.

* Removing assertion on child info (can fail depending on root
memoization).

* merging child info in the overlay when possible.

* child iteration by prefix using child_info.

* Using ChainInfo in frame support. ChainInfo gets redesign to avoid
buffers allocation on every calls.

* Add length of root to the data of child info.

* comments

* Encode compact.

* Remove child info with root.

* Fix try_update condition.

* Comment Ext child root caching.

* Replace tuples by struct with field

* remove StorageTuple alias.

* Fix doc tests, and remove StorageOverlay and ChildStorageOverlay
aliases.

substrate/client/network/src/protocol/light_dispatch.rs

@@ -69,6 +69,8 @@ pub trait LightDispatchNetwork<B: BlockT> {
 		id: RequestId,
 		block: <B as BlockT>::Hash,
 		storage_key: Vec<u8>,
+		child_info: Vec<u8>,
+		child_type: u32,
 		keys: Vec<Vec<u8>>,
 	);
 
@@ -622,6 +624,8 @@ impl<Block: BlockT> Request<Block> {
 					self.id,
 					data.block,
 					data.storage_key.clone(),
+					data.child_info.clone(),
+					data.child_type,
 					data.keys.clone(),
 				),
 			RequestData::RemoteCall(ref data, _) =>
@@ -677,6 +681,7 @@ pub mod tests {
 	use std::sync::Arc;
 	use std::time::Instant;
 	use futures::{Future, sync::oneshot};
+	use primitives::storage::ChildInfo;
 	use sp_runtime::traits::{Block as BlockT, NumberFor, Header as HeaderT};
 	use sp_blockchain::{Error as ClientError, Result as ClientResult};
 	use client_api::{FetchChecker, RemoteHeaderRequest,
@@ -808,7 +813,7 @@ pub mod tests {
 		fn send_header_request(&mut self, _: &PeerId, _: RequestId, _: <<B as BlockT>::Header as HeaderT>::Number) {}
 		fn send_read_request(&mut self, _: &PeerId, _: RequestId, _: <B as BlockT>::Hash, _: Vec<Vec<u8>>) {}
 		fn send_read_child_request(&mut self, _: &PeerId, _: RequestId, _: <B as BlockT>::Hash, _: Vec<u8>,
-			_: Vec<Vec<u8>>) {}
+			_: Vec<u8>, _: u32, _: Vec<Vec<u8>>) {}
 		fn send_call_request(&mut self, _: &PeerId, _: RequestId, _: <B as BlockT>::Hash, _: String, _: Vec<u8>) {}
 		fn send_changes_request(&mut self, _: &PeerId, _: RequestId, _: <B as BlockT>::Hash, _: <B as BlockT>::Hash,
 			_: <B as BlockT>::Hash, _: <B as BlockT>::Hash, _: Option<Vec<u8>>, _: Vec<u8>) {}
@@ -1027,10 +1032,14 @@ pub mod tests {
 		light_dispatch.on_connect(&mut network_interface, peer0.clone(), Roles::FULL, 1000);
 
 		let (tx, response) = oneshot::channel();
+		let child_info = ChildInfo::new_default(b"unique_id_1");
+		let (child_info, child_type) = child_info.info();
 		light_dispatch.add_request(&mut network_interface, RequestData::RemoteReadChild(RemoteReadChildRequest {
 			header: dummy_header(),
 			block: Default::default(),
 			storage_key: b":child_storage:sub".to_vec(),
+			child_info: child_info.to_vec(),
+			child_type,
 			keys: vec![b":key".to_vec()],
 			retry_count: None,
 		}, tx));

substrate/client/network/src/protocol/message.rs

@@ -368,6 +368,11 @@ pub mod generic {
 		pub block: H,
 		/// Child Storage key.
 		pub storage_key: Vec<u8>,
+		/// Child trie source information.
+		pub child_info: Vec<u8>,
+		/// Child type, its required to resolve `child_info`
+		/// content and choose child implementation.
+		pub child_type: u32,
 		/// Storage key.
 		pub keys: Vec<Vec<u8>>,
 	}