fix(archiver): treat re-publish of preloaded protocol contracts as idempotent

[spalladino]

Motivation

The archiver preloads every bundled protocol contract class (and its canonical instance) into its local store at synthetic block 0, before L1 sync. World-state genesis, however, seeds no registration nullifiers for those classes/instances. As a result a first on-chain ContractClassRegistry.publish of a bundled protocol class id is protocol-valid (fresh class-id nullifier + ContractClassPublished log). On replay the archiver recomputes the same class id and unconditionally re-inserts it, but the store throws on the pre-existing block-0 key (Contract class <id> already exists, cannot add again). Because that insert runs inside the block/checkpoint store transaction, the throw aborts persistence, and L1 sync retries the same valid checkpoint indefinitely — a sync stall.

Approach

Make the archiver treat protocol-preloaded entries as idempotent and immutable, guarded at the store layer (the single chokepoint for both the add-throw and the block-gated delete):

• addContractClass / addContractInstance: when the key already exists and it is a protocol class id / magic protocol address, treat the (re-)publish as a no-op and keep the existing block-0 entry — crucially without bumping its recorded block number. Genuine non-protocol duplicates still throw unchanged.
• deleteContractClass / deleteContractInstance: skip deletion for protocol entries, so a reorg of the publishing block can never roll out the preload.

Keeping the preload at block 0 is deliberate: deleteContractClass only deletes when the stored l2BlockNumber >= blockNumber, so block 0 makes protocol entries survive any reorg; bumping to the publish block would let a deep reorg delete them.

The instance-side guards are defensive only: on-chain publish_for_public_execution always emits the derived address, never a magic address, so the instance store is not reached with a magic address via the on-chain replay path today — the guards exist for symmetry and to protect future code paths.

This is a non-breaking, node-local resilience fix. A follow-up PR (PR2) seeds the protocol registration nullifiers into world-state genesis so the on-chain re-publish is rejected at the protocol level — the root-cause fix for the class path.

Changes

• protocol-contracts: add isProtocolContractClass(classId) (sibling of the existing isProtocolContract(address)), backed by a set of the generated ProtocolContractClassId values.
• archiver: idempotent add + protected delete for protocol classes and instances in ContractClassStore / ContractInstanceStore.
• archiver (tests): store unit tests (idempotent re-add stays queryable with block-0 / bytecode-commitment preserved, protected delete, non-protocol duplicate still throws — for both classes and instances) and an A-1257 integration test that preloads protocol contracts, builds an L2Block carrying a ContractClassPublished log for a bundled class id, and asserts addProposedBlock commits and the class stays queryable.

Fixes A-1257

[AztecBot]

Flakey Tests

🤖 says: This CI run detected 2 tests that failed, but were tolerated due to a .test_patterns.yml entry.

\033FLAKED\033 (8;;http://ci.aztec-labs.com/d3a75831b3616f8d�d3a75831b3616f8d8;;�): yarn-project/kv-store/scripts/run_test.sh src/bench/sqlite-opfs-encrypted/map_bench.test.ts (1s) (code: 0)
\033FLAKED\033 (8;;http://ci.aztec-labs.com/c4ddebf2cfa9e874�c4ddebf2cfa9e8748;;�): yarn-project/kv-store/scripts/run_test.sh src/sqlite-opfs/internal/ordered-binary-browser.test.ts (1s) (code: 0)

[AztecBot]

❌ Failed to cherry-pick to v4 due to conflicts. (🤖) View backport run.