BlockId removal: refactor: HeaderBackend::header (#12874)

* BlockId removal: refactor: HeaderBackend::header

It changes the arguments of:
- `HeaderBackend::header`,
- `Client::header`,
- `PeersClient::header`
- `ChainApi::block_header`

methods from: `BlockId<Block>` to: `Block::Hash`

This PR is part of BlockId::Number refactoring analysis (paritytech/substrate#11292)

* non-trivial usages of haeder(block_id) refactored

This may required introduction of dedicated function:
header_for_block_num

* fmt

* fix

* doc fixed

* ".git/.scripts/fmt.sh"

* BlockId removal: refactor: HeaderBackend::expect_header

It changes the arguments of `HeaderBackend::expect_header` method from: `BlockId<Block>` to: `Block::Hash`

* ".git/.scripts/fmt.sh"

* readme updated

* ".git/.scripts/fmt.sh"

* fix

Co-authored-by: parity-processbot <>

substrate/client/rpc/src/chain/chain_full.rs

@@ -62,7 +62,7 @@ where
 	}
 
 	fn header(&self, hash: Option<Block::Hash>) -> Result<Option<Block::Header>, Error> {
-		self.client.header(BlockId::Hash(self.unwrap_or_best(hash))).map_err(client_err)
+		self.client.header(self.unwrap_or_best(hash)).map_err(client_err)
 	}
 
 	fn block(&self, hash: Option<Block::Hash>) -> Result<Option<SignedBlock<Block>>, Error> {
@@ -130,7 +130,7 @@ fn subscribe_headers<Block, Client, F, G, S>(
 {
 	// send current head right at the start.
 	let maybe_header = client
-		.header(BlockId::Hash(best_block_hash()))
+		.header(best_block_hash())
 		.map_err(client_err)
 		.and_then(|header| header.ok_or_else(|| Error::Other("Best header missing.".into())))
 		.map_err(|e| log::warn!("Best header error {:?}", e))

substrate/client/rpc/src/chain/mod.rs

@@ -31,8 +31,8 @@ use jsonrpsee::{core::RpcResult, types::SubscriptionResult, SubscriptionSink};
 use sc_client_api::BlockchainEvents;
 use sp_rpc::{list::ListOrValue, number::NumberOrHex};
 use sp_runtime::{
-	generic::{BlockId, SignedBlock},
-	traits::{Block as BlockT, Header, NumberFor},
+	generic::SignedBlock,
+	traits::{Block as BlockT, NumberFor},
 };
 
 use self::error::Error;
@@ -80,11 +80,7 @@ where
 					))
 				})?;
 				let block_num = <NumberFor<Block>>::from(block_num);
-				Ok(self
-					.client()
-					.header(BlockId::number(block_num))
-					.map_err(client_err)?
-					.map(|h| h.hash()))
+				self.client().hash(block_num).map_err(client_err)
 			},
 		}
 	}

substrate/client/rpc/src/dev/mod.rs

@@ -87,7 +87,7 @@ where
 			let parent_hash = *block.header().parent_hash();
 			let parent_header = self
 				.client
-				.header(BlockId::Hash(parent_hash))
+				.header(parent_hash)
 				.map_err(|e| Error::BlockQueryError(Box::new(e)))?;
 			if let Some(header) = parent_header {
 				header