Bastian Köcher
ca5f10567a
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 <>
Integration of the GRANDPA finality gadget into Substrate.
This crate is unstable and the API and usage may change.
This crate provides a long-running future that produces finality notifications.
Usage
First, create a block-import wrapper with the block_import function. The
GRANDPA worker needs to be linked together with this block import object, so
a LinkHalf is returned as well. All blocks imported (from network or
consensus or otherwise) must pass through this wrapper, otherwise consensus
is likely to break in unexpected ways.
Next, use the LinkHalf and a local configuration to run_grandpa_voter.
This requires a Network implementation. The returned future should be
driven to completion and will finalize blocks in the background.
Changing authority sets
The rough idea behind changing authority sets in GRANDPA is that at some point, we obtain agreement for some maximum block height that the current set can finalize, and once a block with that height is finalized the next set will pick up finalization from there.
Technically speaking, this would be implemented as a voting rule which says, "if there is a signal for a change in N blocks in block B, only vote on chains with length NUM(B) + N if they contain B". This conditional-inclusion logic is complex to compute because it requires looking arbitrarily far back in the chain.
Instead, we keep track of a list of all signals we've seen so far (across all forks), sorted ascending by the block number they would be applied at. We never vote on chains with number higher than the earliest handoff block number (this is num(signal) + N). When finalizing a block, we either apply or prune any signaled changes based on whether the signaling block is included in the newly-finalized chain.
License: GPL-3.0-or-later WITH Classpath-exception-2.0