smart-contract V6 review small tweaks

[jpnovais]

This PR

• improves DataSubmittedV3 names consistency,
• tries blob/data submission validation more efficient

Since we are making a change & audit, maybe it's a good opportunity to assess the following points

Other Improvement Suggestions

Blob Submission

Current Interface

  function submitBlobs(
    BlobSubmissionData[] calldata _blobSubmissionData,
    bytes32 _parentShnarf,
    bytes32 _finalBlobShnarf
  ) external;

  struct BlobSubmissionData {
    SupportingSubmissionDataV2 submissionData;
    uint256 dataEvaluationClaim;
    bytes kzgCommitment;
    bytes kzgProof;
  }

  struct SupportingSubmissionDataV2 {
    bytes32 finalStateRootHash;
    uint256 firstBlockInData;
    uint256 finalBlockInData;
    bytes32 snarkHash;
  }

The list of SupportingSubmissionDataV2 has redundant fields (first/final)BlockInData, because _blobSubmissionData[i].subissionData.firstBlockInData must be equal to its ancestor _blobSubmissionData[i-1].subissionData.finalBlockInData;
We can keep just finalBlockInData and pass only firstBlockInData for the first bock in submitBlobs(..). SupportingSubmissionDataV2’s fields can be included in the parent struct BlobSubmissionData.

This simplification will:

• allow to remove SupportingSubmissionDataV2 struct, which is sometimes confused with SubmissionDataV2 struct used for blob submission as call data;
• save gas on call data by not sending redundant fields;
• simplify input validation code _validateSubmissionData, potentially saving more gas;

New Interface Suggestion

function submitBlobs(
  BlobSubmissionData[] calldata _blobSubmissionData,
  uint256 firstBlockInData;
  bytes32 _parentShnarf,
  bytes32 _finalBlobShnarf
) external;

struct BlobSubmissionDataV2 { 
  uint256 finalBlockInData;
  bytes32 finalStateRootHash;
  bytes32 snarkHash;
  uint256 dataEvaluationClaim;
  bytes kzgCommitment;
  bytes kzgProof;
}

Block Finalization

_computeLastFinalizedState relies on "timestamp The final timestamp in the finalization.", should it use finalStateRootHash? Sequencer(s) can have different blocks at same timestamp.

[codecov-commenter]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 70.11%. Comparing base (74529e6) to head (c475447).

Additional details and impacted files

@@            Coverage Diff            @@
##               main     #207   +/-   ##
=========================================
  Coverage     70.11%   70.11%           
  Complexity     1042     1042           
=========================================
  Files           286      286           
  Lines         11827    11829    +2     
  Branches       1087     1088    +1     
=========================================
+ Hits           8292     8294    +2     
  Misses         3065     3065           
  Partials        470      470           

Flag	Coverage Δ
hardhat	98.69% <100.00%> (+<0.01%)	⬆️
kotlin	67.69% <ø> (ø)

Files with missing lines	Coverage Δ
contracts/contracts/LineaRollup.sol	98.73% <100.00%> (+0.01%)	⬆️