fix(fast-inbox): address the review findings across archiver, sequencer, validator and prover

l1-contracts/l1-artifacts/scripts/generate-artifacts.sh

@@ -15,6 +15,7 @@ contracts=(
   "EscapeHatch"
   "SlashingProposer"
   "EmpireBase"
+  "EpochProofExtLib"
   "RollupOperationsExtLib"
   "ValidatorOperationsExtLib"
   "RewardExtLib"

noir-projects/fnd/noir-protocol-circuits/crates/rollup-lib/src/tests/rollup_fixture_builder.nr

@@ -28,7 +28,7 @@ use types::{
     },
     hash::{poseidon2_hash, poseidon2_hash_with_separator},
     merkle_tree::{
-        append_only_tree::append_leaves_to_snapshot, compute_empty_tree_root, MerkleTree,
+        append_only_tree::append_leaves_to_snapshot, MerkleTree,
         test_utils::SingleSubtreeMerkleTree,
     },
     proof::proof_data::{AvmV2ProofData, ProofData},
@@ -139,52 +139,6 @@ impl RollupFixtureBuilder {
         (previous_snapshot, sibling_path_for_insertion)
     }
 
-    pub fn build_l1_to_l2_message_subtree_for_insertion(
-        self,
-        slot_number: Field,
-    ) -> (AppendOnlyTreeSnapshot, [Field; L1_TO_L2_MSG_TREE_HEIGHT - L1_TO_L2_MSG_SUBTREE_HEIGHT], AppendOnlyTreeSnapshot) {
-        // Create a subtree of size 4 filled with subtree roots before the current slot.
-        let new_slot_index = self.get_l1_to_l2_message_next_available_leaf_index(slot_number - 1)
-             as u32
-            >> L1_TO_L2_MSG_SUBTREE_HEIGHT;
-        let start_slot_index = new_slot_index - new_slot_index % 4;
-        let mut subtree_roots = [0; 4];
-        for i in start_slot_index..new_slot_index {
-            subtree_roots[i % 4] =
-                self.get_l1_to_l2_message_subtree_root(slot_number - 4 + i as Field);
-        }
-        let empty_subtree_root = compute_empty_tree_root::<L1_TO_L2_MSG_SUBTREE_HEIGHT>();
-        subtree_roots[new_slot_index % 4] = empty_subtree_root;
-
-        let mut tree = SingleSubtreeMerkleTree::<4, 2, L1_TO_L2_MSG_TREE_HEIGHT - L1_TO_L2_MSG_SUBTREE_HEIGHT>::new_tree_roots_at_index::<L1_TO_L2_MSG_SUBTREE_HEIGHT>(
-            subtree_roots,
-            start_slot_index as Field,
-        );
-        let previous_snapshot = AppendOnlyTreeSnapshot {
-            root: tree.get_root(),
-            next_available_leaf_index: self.get_l1_to_l2_message_next_available_leaf_index(
-                slot_number - 1,
-            ),
-        };
-
-        // Get the sibling path for inserting the current l1-to-l2 messages.
-        let sibling_path_for_insertion = tree.get_sibling_path(new_slot_index as Field);
-
-        // Insert subtree of the current l1-to-l2 messages.
-        tree.update_leaf(
-            new_slot_index as Field,
-            self.get_l1_to_l2_message_subtree_root(slot_number),
-        );
-        let new_snapshot = AppendOnlyTreeSnapshot {
-            root: tree.get_root(),
-            next_available_leaf_index: self.get_l1_to_l2_message_next_available_leaf_index(
-                slot_number,
-            ),
-        };
-
-        (previous_snapshot, sibling_path_for_insertion, new_snapshot)
-    }
-
     /// Builds a per-block L1-to-L2 message bundle appended to an empty tree, returning
     /// `(previous_snapshot, leaves, frontier_hint, new_snapshot)`. The resulting `new_snapshot` is exactly what the
     /// block root circuit recomputes from the same inputs.
@@ -588,10 +542,6 @@ impl RollupFixtureBuilder {
         }
     }
 
-    fn get_l1_to_l2_message_subtree_root(_self: Self, slot_number: Field) -> Field {
-        slot_number * 7639901
-    }
-
     fn get_l1_to_l2_message_next_available_leaf_index(_self: Self, slot_number: Field) -> Field {
         (slot_number + 1) * (1 << L1_TO_L2_MSG_SUBTREE_HEIGHT) as Field
     }

yarn-project/archiver/src/errors.ts

@@ -109,11 +109,12 @@ export class BlockAlreadyCheckpointedError extends Error {
 export class InboxMessagePrefixChangedError extends Error {
   constructor(
     public readonly totalMessageCount: bigint,
-    public readonly expected: Fr,
+    /** The rolling hash the prefix was expected to have, when a caller knows it for this exact count. */
+    public readonly expected: Fr | undefined,
     public readonly actual: Fr | undefined,
   ) {
     super(
-      `Inbox message prefix at count ${totalMessageCount} changed from ${expected.toString()} to ` +
+      `Inbox message prefix at count ${totalMessageCount} changed from ${expected?.toString() ?? 'unavailable'} to ` +
         `${actual?.toString() ?? 'unavailable'} while a replacement was being prepared`,
     );
     this.name = 'InboxMessagePrefixChangedError';

yarn-project/archiver/src/modules/data_store_updater.ts

@@ -407,7 +407,7 @@ export class ArchiverDataStoreUpdater {
     if (block === undefined || block.header.getBlockNumber() !== blockNumber) {
       throw new Error(`Block ${blockNumber} is missing from the store`);
     }
-    return BigInt(block.header.state.l1ToL2MessageTree.nextAvailableLeafIndex);
+    return blockLeafCount(block);
   }
 
   /**