sc-block-builder: Remove BlockBuilderProvider (#2099)

The `BlockBuilderProvider` was a trait that was defined in
`sc-block-builder`. The trait was implemented for `Client`. This
basically meant that you needed to import `sc-block-builder` any way to
have access to the block builder. So, this trait was not providing any
real value. This pull request is removing the said trait. Instead of the
trait it introduces a builder for creating a `BlockBuilder`. The builder
currently has the quite fabulous name `BlockBuilderBuilder` (I'm open to
any better name 😅). The rest of the pull request is about
replacing the old trait with the new builder.

# Downstream code changes

If you used `new_block` or `new_block_at` before you now need to switch
it over to the new `BlockBuilderBuilder` pattern:

```rust
// `new` requires a type that implements `CallApiAt`. 
let mut block_builder = BlockBuilderBuilder::new(client)
                // Then you need to specify the hash of the parent block the block will be build on top of
		.on_parent_block(at)
                // The block builder also needs the block number of the parent block. 
                // Here it is fetched from the given `client` using the `HeaderBackend`
                // However, there also exists `with_parent_block_number` for directly passing the number
		.fetch_parent_block_number(client)
		.unwrap()
                // Enable proof recording if required. This call is optional.
		.enable_proof_recording()
                // Pass the digests. This call is optional.
                .with_inherent_digests(digests)
		.build()
		.expect("Creates new block builder");
```

---------

Co-authored-by: Sebastian Kunert <skunert49@gmail.com>
Co-authored-by: command-bot <>

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

@@ -35,6 +35,7 @@ use crate::{
 };
 use futures::{future, stream::FuturesUnordered, Future, FutureExt, StreamExt};
 use parking_lot::Mutex;
+use sc_block_builder::BlockBuilderBuilder;
 use sc_client_api::{Backend as BackendT, BlockchainEvents, FinalityNotifications, HeaderBackend};
 use sc_consensus::{
 	BlockImport, BlockImportParams, BoxJustificationImport, ForkChoiceStrategy, ImportResult,
@@ -741,7 +742,6 @@ async fn correct_beefy_payload() {
 #[tokio::test]
 async fn beefy_importing_justifications() {
 	use futures::{future::poll_fn, task::Poll};
-	use sc_block_builder::BlockBuilderProvider;
 	use sc_client_api::BlockBackend;
 
 	sp_tracing::try_init_simple();
@@ -774,8 +774,10 @@ async fn beefy_importing_justifications() {
 			.and_then(|j| j.get(BEEFY_ENGINE_ID).cloned())
 	};
 
-	let builder = full_client
-		.new_block_at(full_client.chain_info().genesis_hash, Default::default(), false)
+	let builder = BlockBuilderBuilder::new(&*full_client)
+		.on_parent_block(full_client.genesis_hash())
+		.with_parent_block_number(0)
+		.build()
 		.unwrap();
 	let block = builder.build().unwrap().block;
 	let hashof1 = block.header.hash();
@@ -792,7 +794,11 @@ async fn beefy_importing_justifications() {
 
 	// Import block 2 with "valid" justification (beefy pallet genesis block not yet reached).
 	let block_num = 2;
-	let builder = full_client.new_block_at(hashof1, Default::default(), false).unwrap();
+	let builder = BlockBuilderBuilder::new(&*full_client)
+		.on_parent_block(hashof1)
+		.with_parent_block_number(1)
+		.build()
+		.unwrap();
 	let block = builder.build().unwrap().block;
 	let hashof2 = block.header.hash();
 
@@ -824,7 +830,11 @@ async fn beefy_importing_justifications() {
 
 	// Import block 3 with valid justification.
 	let block_num = 3;
-	let builder = full_client.new_block_at(hashof2, Default::default(), false).unwrap();
+	let builder = BlockBuilderBuilder::new(&*full_client)
+		.on_parent_block(hashof2)
+		.with_parent_block_number(2)
+		.build()
+		.unwrap();
 	let block = builder.build().unwrap().block;
 	let hashof3 = block.header.hash();
 	let proof = crate::justification::tests::new_finality_proof(block_num, &good_set, keys);
@@ -858,7 +868,11 @@ async fn beefy_importing_justifications() {
 
 	// Import block 4 with invalid justification (incorrect validator set).
 	let block_num = 4;
-	let builder = full_client.new_block_at(hashof3, Default::default(), false).unwrap();
+	let builder = BlockBuilderBuilder::new(&*full_client)
+		.on_parent_block(hashof3)
+		.with_parent_block_number(3)
+		.build()
+		.unwrap();
 	let block = builder.build().unwrap().block;
 	let hashof4 = block.header.hash();
 	let keys = &[BeefyKeyring::Alice];