From 0e733fcff13036085ba4a6e9494e34005ba68a45 Mon Sep 17 00:00:00 2001
From: Chris Buckland <cpbuckland88@gmail.com>
Date: Thu, 18 Jan 2024 12:57:29 +0000
Subject: [PATCH] Added both block basefee and blob basefee to batch spending
 report

---
 src/bridge/SequencerInbox.sol             | 20 ++++++++++--------
 test/contract/sequencerInbox.spec.4844.ts | 25 ++++++++++++++++++++---
 test/foundry/SequencerInbox.t.sol         |  4 +++-
 3 files changed, 37 insertions(+), 12 deletions(-)

diff --git a/src/bridge/SequencerInbox.sol b/src/bridge/SequencerInbox.sol
index 7aef44b8..7cecec64 100644
--- a/src/bridge/SequencerInbox.sol
+++ b/src/bridge/SequencerInbox.sol
@@ -418,6 +418,9 @@ contract SequencerInbox is DelegateCallAware, GasRefundEnabled, ISequencerInbox
             afterDelayedMessagesRead
         );
 
+        // we use addSequencerL2BatchImpl for submitting the message
+        // normally this would also submit a batch spending report but that is skipped if we pass
+        // an empty call data size, then we submit a separate batch spending report later
         (
             uint256 seqMessageIndex,
             bytes32 beforeAcc,
@@ -453,11 +456,7 @@ contract SequencerInbox is DelegateCallAware, GasRefundEnabled, ISequencerInbox
 
         // submit a batch spending report to refund the entity that produced the blob batch data
         uint256 blobBasefee = blobBasefeeReader.getBlobBaseFee();
-
-        // TODO: This report the gas spending using the blob basefee, however the actual spending actually involve
-        //       2 parts: 1. data cost priced in blob basefee, 2. tx cost priced in block basefee
-        //       We might need to change the batch spending report format so both costs are reported.
-        submitBatchSpendingReport(dataHash, seqMessageIndex, blobBasefee);
+        submitBatchSpendingReport(dataHash, seqMessageIndex, block.basefee, blobBasefee);
     }
 
     function addSequencerL2Batch(
@@ -625,7 +624,8 @@ contract SequencerInbox is DelegateCallAware, GasRefundEnabled, ISequencerInbox
     function submitBatchSpendingReport(
         bytes32 dataHash,
         uint256 seqMessageIndex,
-        uint256 gasPrice
+        uint256 gasPrice,
+        uint256 blobBaseFeePrice
     ) internal {
         bytes memory spendingReportMsg;
         address batchPoster = msg.sender;
@@ -646,12 +646,16 @@ contract SequencerInbox is DelegateCallAware, GasRefundEnabled, ISequencerInbox
                 uint64(extraGas)
             );
         } else {
+            // when a blob base fee is supplied we include it into the batch spending report
             spendingReportMsg = abi.encodePacked(
                 block.timestamp,
                 batchPoster,
                 dataHash,
                 seqMessageIndex,
-                gasPrice
+                gasPrice,
+                // we add an empty extraGas since the parsing code expects a value here
+                uint64(0),
+                blobBaseFeePrice
             );
         }
 
@@ -691,7 +695,7 @@ contract SequencerInbox is DelegateCallAware, GasRefundEnabled, ISequencerInbox
         totalDelayedMessagesRead = afterDelayedMessagesRead;
 
         if (calldataLengthPosted > 0) {
-            submitBatchSpendingReport(dataHash, seqMessageIndex, block.basefee);
+            submitBatchSpendingReport(dataHash, seqMessageIndex, block.basefee, 0);
         }
     }
 
diff --git a/test/contract/sequencerInbox.spec.4844.ts b/test/contract/sequencerInbox.spec.4844.ts
index cb7d51b1..681e78dd 100644
--- a/test/contract/sequencerInbox.spec.4844.ts
+++ b/test/contract/sequencerInbox.spec.4844.ts
@@ -445,8 +445,11 @@ describe('SequencerInbox', async () => {
     const batchSendTx = await Toolkit4844.getTx(txHash)
     const blobHashes = (batchSendTx as any)['blobVersionedHashes'] as string[]
     const batchSendReceipt = await Toolkit4844.getTxReceipt(txHash)
-    const { timestamp: blockTimestamp, number: blockNumber } =
-      await wallet.provider.getBlock(batchSendReceipt.blockNumber)
+    const {
+      timestamp: blockTimestamp,
+      number: blockNumber,
+      baseFeePerGas,
+    } = await wallet.provider.getBlock(batchSendReceipt.blockNumber)
 
     const timeBounds = await getTimeBounds(
       blockNumber,
@@ -516,8 +519,12 @@ describe('SequencerInbox', async () => {
       '0x' + inboxMsgDeliveredEvent.data.substring(106, 170)
     const spendingSeqMessageIndex =
       '0x' + inboxMsgDeliveredEvent.data.substring(170, 234)
-    const spendingBlobBasefee =
+    const spendingBlockBaseFee =
       '0x' + inboxMsgDeliveredEvent.data.substring(234, 298)
+    const spendingExtraGas =
+      '0x' + inboxMsgDeliveredEvent.data.substring(298, 314)
+    const spendingBlobBasefee =
+      '0x' + inboxMsgDeliveredEvent.data.substring(314, 378)
 
     expect(
       BigNumber.from(spendingTimestamp).eq(blockTimestamp),
@@ -531,6 +538,18 @@ describe('SequencerInbox', async () => {
       BigNumber.from(spendingSeqMessageIndex).eq(sequenceNumber),
       'spending seq message index'
     ).to.eq(true)
+
+    if (baseFeePerGas == null) {
+      throw new Error('Missing base fee')
+    }
+    expect(
+      BigNumber.from(spendingBlockBaseFee).eq(baseFeePerGas),
+      `spending basefee: ${BigNumber.from(spendingBlockBaseFee).toString()}`
+    ).to.eq(true)
+    expect(
+      BigNumber.from(spendingExtraGas).eq(0),
+      `spending extra gas: ${BigNumber.from(spendingExtraGas).toString()}`
+    ).to.eq(true)
     // we expect a very low - 1 - basefee since we havent sent many blobs
     expect(
       BigNumber.from(spendingBlobBasefee).eq(1),
diff --git a/test/foundry/SequencerInbox.t.sol b/test/foundry/SequencerInbox.t.sol
index 7af81507..f947e8ac 100644
--- a/test/foundry/SequencerInbox.t.sol
+++ b/test/foundry/SequencerInbox.t.sol
@@ -106,7 +106,9 @@ contract SequencerInboxTest is Test {
             msg.sender,
             dataHash,
             sequenceNumber,
-            block.basefee
+            block.basefee,
+            uint64(0),
+            uint256(0)
         );
         bytes32 beforeAcc = bytes32(0);
         bytes32 delayedAcc = bridge.delayedInboxAccs(delayedMessagesRead - 1);