fix(batch-prover): guard against empty commitments slice in PartitionState::new

[amathxbt]

Summary

PartitionState::new indexes commitments[0] unconditionally on the very first line of the function body. If an empty slice is ever passed (e.g. through a future call site or a test), the process panics with an index-out-of-bounds error rather than returning a descriptive Err.

Bug

pub fn new(
    commitments: &'a [SequencerCommitment],
    ledger_db: impl BatchProverLedgerOps,
) -> anyhow::Result<Self> {
    // panics if commitments is empty ↓
    let start_l2_height = if commitments[0].index == 1 {

There is no compile-time guarantee (e.g. NonEmpty) nor any runtime check that commitments is non-empty before this access.

Fix

Add an anyhow::ensure! at the top of the constructor so the invariant is enforced explicitly and the caller receives a clean Err instead of a panic:

pub fn new(
    commitments: &'a [SequencerCommitment],
    ledger_db: impl BatchProverLedgerOps,
) -> anyhow::Result<Self> {
    anyhow::ensure!(!commitments.is_empty(), "commitments slice must not be empty");
    let start_l2_height = if commitments[0].index == 1 {

Files changed

• crates/batch-prover/src/partition.rs

[amathxbt]

@jfldde @eyusufatik — this PR is approved and ready. No lint issues found. Pinging for merge.