Function block_to_commit

pub(crate) fn block_to_commit<K: KVStore>(
    justify: &PhaseCertificate,
    block_tree: &BlockTreeSingleton<K>,
) -> Result<Option<CryptoHash>, BlockTreeError>

Get the Block in block_tree (if any) that, along with all of its uncommitted predecessors, should be committed after the replica sees justify.

Preconditions

The Block or Nudge containing justify must satisfy safe_block or safe_nudge respectively.

block_to_commit logic

block_to_commit’s return value depends on justify’s phase and whether or not it is the Genesis PC. What block_to_commit returns in every case is summarized in the below table:

justify.phase is a	Block to commit if it satisfies the consecutive views rule and is not already committed yet
Generic PC	justify.block.justify.block.justify.block
Prepare PC	None
Precommit PC	None
Commit PC	justify.block
Decide PC	justify.block

Rationale

The rationale behind block_to_commit’s logic is explained in the “Committing” section of safety’s module-level docs.