feat: sum transaction fees and pay on l1 (AztecProtocol#6522)

Add `totalFees` to block header. Update the spec.

Note: we could have had the L1 rollup contract iterate over all the
tx_effects and pay out that way. Doing it ourselves in the circuit feels
cheaper though, and maybe safer for a world where:
1. tx_effects are spread over multiple l1 blocks
2. tx_effects are published as blobs so we wouldn't have direct access
to math over them on l1.

barretenberg/cpp/pil/avm/constants.pil

@@ -8,22 +8,22 @@ namespace constants(256);
     pol PORTAL_SELECTOR = 2;
 
     // NOTE: constant expression evaluation does not seem to be supported yet in pil
-    // pol START_GLOBAL_VARIABLES = CALL_CONTEXT_LENGTH + HEADER_LENGTH = 6 + 22 = 28
+    // pol START_GLOBAL_VARIABLES = CALL_CONTEXT_LENGTH + HEADER_LENGTH = 6 + 23 = 29
 
     // Global Variables
-    pol CHAIN_ID_SELECTOR = 28;
-    pol VERSION_SELECTOR = 29;
-    pol BLOCK_NUMBER_SELECTOR = 30; 
-    pol TIMESTAMP_SELECTOR = 31; 
-    pol COINBASE_SELECTOR = 32; 
+    pol CHAIN_ID_SELECTOR = 29;
+    pol VERSION_SELECTOR = 30;
+    pol BLOCK_NUMBER_SELECTOR = 31; 
+    pol TIMESTAMP_SELECTOR = 32; 
+    pol COINBASE_SELECTOR = 33; 
 
-    pol END_GLOBAL_VARIABLES = 28 + 8; // We only use the first 5 of 8 global variables for now
+    pol END_GLOBAL_VARIABLES = 29 + 8; // We only use the first 5 of 8 global variables for now
 
-    pol START_SIDE_EFFECT_COUNTER = 36;
+    pol START_SIDE_EFFECT_COUNTER = 37;
 
     // Gas
-    pol FEE_PER_DA_GAS_SELECTOR = 37;
-    pol FEE_PER_L2_GAS_SELECTOR = 38;
+    pol FEE_PER_DA_GAS_SELECTOR = 38;
+    pol FEE_PER_L2_GAS_SELECTOR = 39;
 
-    pol TRANSACTION_FEE_SELECTOR = 39;
+    pol TRANSACTION_FEE_SELECTOR = 40;
 

barretenberg/cpp/src/barretenberg/relations/generated/avm/avm_main.hpp

@@ -915,63 +915,63 @@ template <typename FF_> class avm_mainImpl {
         {
             Avm_DECLARE_VIEWS(83);
 
-            auto tmp = (avm_main_sel_op_fee_per_da_gas * (avm_kernel_kernel_sel - FF(37)));
+            auto tmp = (avm_main_sel_op_fee_per_da_gas * (avm_kernel_kernel_sel - FF(38)));
             tmp *= scaling_factor;
             std::get<83>(evals) += tmp;
         }
         // Contribution 84
         {
             Avm_DECLARE_VIEWS(84);
 
-            auto tmp = (avm_main_sel_op_fee_per_l2_gas * (avm_kernel_kernel_sel - FF(38)));
+            auto tmp = (avm_main_sel_op_fee_per_l2_gas * (avm_kernel_kernel_sel - FF(39)));
             tmp *= scaling_factor;
             std::get<84>(evals) += tmp;
         }
         // Contribution 85
         {
             Avm_DECLARE_VIEWS(85);
 
-            auto tmp = (avm_main_sel_op_transaction_fee * (avm_kernel_kernel_sel - FF(39)));
+            auto tmp = (avm_main_sel_op_transaction_fee * (avm_kernel_kernel_sel - FF(40)));
             tmp *= scaling_factor;
             std::get<85>(evals) += tmp;
         }
         // Contribution 86
         {
             Avm_DECLARE_VIEWS(86);
 
-            auto tmp = (avm_main_sel_op_chain_id * (avm_kernel_kernel_sel - FF(28)));
+            auto tmp = (avm_main_sel_op_chain_id * (avm_kernel_kernel_sel - FF(29)));
             tmp *= scaling_factor;
             std::get<86>(evals) += tmp;
         }
         // Contribution 87
         {
             Avm_DECLARE_VIEWS(87);
 
-            auto tmp = (avm_main_sel_op_version * (avm_kernel_kernel_sel - FF(29)));
+            auto tmp = (avm_main_sel_op_version * (avm_kernel_kernel_sel - FF(30)));
             tmp *= scaling_factor;
             std::get<87>(evals) += tmp;
         }
         // Contribution 88
         {
             Avm_DECLARE_VIEWS(88);
 
-            auto tmp = (avm_main_sel_op_block_number * (avm_kernel_kernel_sel - FF(30)));
+            auto tmp = (avm_main_sel_op_block_number * (avm_kernel_kernel_sel - FF(31)));
             tmp *= scaling_factor;
             std::get<88>(evals) += tmp;
         }
         // Contribution 89
         {
             Avm_DECLARE_VIEWS(89);
 
-            auto tmp = (avm_main_sel_op_coinbase * (avm_kernel_kernel_sel - FF(32)));
+            auto tmp = (avm_main_sel_op_coinbase * (avm_kernel_kernel_sel - FF(33)));
             tmp *= scaling_factor;
             std::get<89>(evals) += tmp;
         }
         // Contribution 90
         {
             Avm_DECLARE_VIEWS(90);
 
-            auto tmp = (avm_main_sel_op_timestamp * (avm_kernel_kernel_sel - FF(31)));
+            auto tmp = (avm_main_sel_op_timestamp * (avm_kernel_kernel_sel - FF(32)));
             tmp *= scaling_factor;
             std::get<90>(evals) += tmp;
         }

barretenberg/cpp/src/barretenberg/vm/avm_trace/aztec_constants.hpp

@@ -109,8 +109,9 @@ const size_t ROLLUP_VALIDATION_REQUESTS_LENGTH = MAX_BLOCK_NUMBER_LENGTH;
 const size_t STATE_REFERENCE_LENGTH = APPEND_ONLY_TREE_SNAPSHOT_LENGTH + PARTIAL_STATE_REFERENCE_LENGTH;
 const size_t TX_CONTEXT_LENGTH = 2 + GAS_SETTINGS_LENGTH;
 const size_t TX_REQUEST_LENGTH = 2 + TX_CONTEXT_LENGTH + FUNCTION_DATA_LENGTH;
-const size_t HEADER_LENGTH =
-    APPEND_ONLY_TREE_SNAPSHOT_LENGTH + CONTENT_COMMITMENT_LENGTH + STATE_REFERENCE_LENGTH + GLOBAL_VARIABLES_LENGTH;
+const size_t TOTAL_FEES_LENGTH = 1;
+const size_t HEADER_LENGTH = APPEND_ONLY_TREE_SNAPSHOT_LENGTH + CONTENT_COMMITMENT_LENGTH + STATE_REFERENCE_LENGTH +
+                             GLOBAL_VARIABLES_LENGTH + TOTAL_FEES_LENGTH;
 const size_t PRIVATE_CIRCUIT_PUBLIC_INPUTS_LENGTH =
     CALL_CONTEXT_LENGTH + 4 + MAX_BLOCK_NUMBER_LENGTH + (READ_REQUEST_LENGTH * MAX_NOTE_HASH_READ_REQUESTS_PER_CALL) +
     (READ_REQUEST_LENGTH * MAX_NULLIFIER_READ_REQUESTS_PER_CALL) +
@@ -172,7 +173,7 @@ const size_t KERNEL_CIRCUIT_PUBLIC_INPUTS_LENGTH = ROLLUP_VALIDATION_REQUESTS_LE
                                                    PARTIAL_STATE_REFERENCE_LENGTH + 1 + AZTEC_ADDRESS_LENGTH;
 const size_t CONSTANT_ROLLUP_DATA_LENGTH = APPEND_ONLY_TREE_SNAPSHOT_LENGTH + 4 + GLOBAL_VARIABLES_LENGTH;
 const size_t BASE_OR_MERGE_PUBLIC_INPUTS_LENGTH =
-    CONSTANT_ROLLUP_DATA_LENGTH + PARTIAL_STATE_REFERENCE_LENGTH + PARTIAL_STATE_REFERENCE_LENGTH + 4;
+    CONSTANT_ROLLUP_DATA_LENGTH + PARTIAL_STATE_REFERENCE_LENGTH + PARTIAL_STATE_REFERENCE_LENGTH + 5;
 const size_t ENQUEUE_PUBLIC_FUNCTION_CALL_RETURN_LENGTH = 2 + FUNCTION_DATA_LENGTH + CALL_CONTEXT_LENGTH;
 const size_t GET_NOTES_ORACLE_RETURN_LENGTH = 674;
 const size_t NOTE_HASHES_NUM_BYTES_PER_BASE_ROLLUP = 2048;

docs/docs/protocol-specs/gas-and-fees/kernel-tracking.md

@@ -78,6 +78,7 @@ CombinedConstantData --> TxContext
 
 class Header {
     +GlobalVariables global_variables
+    +Fr total_fees
 }
 Header --> GlobalVariables
 
@@ -538,10 +539,12 @@ The interplay between these two `revert_code`s is as follows:
 | 1                    | 1                         | 3                              |
 | 2 or 3               | (any)                     | (unchanged)                    |
 
-## Base Rollup Kernel Circuit
+## Rollup Kernel Circuits
 
 The base rollup kernel circuit takes in a `KernelData`, which contains a `KernelCircuitPublicInputs`, which it uses to compute the `transaction_fee`.
 
 Additionally, it verifies that the max fees per gas specified by the user are greater than the current block's fees per gas. It also verifies the `constant_data.global_variables.gas_fees` are correct.
 
 After the public data writes specific to this transaction have been processed, and a new tree root is produced, the kernel circuit injects an additional public data write based upon that root which deducts the transaction fee from the `fee_payer`'s balance.
+
+The calculated trasaction fee is set as output on the base rollup as `accumulated_fees`. Each subsequent merge rollup circuit sums this value from both of its inputs. The root rollup circuit then uses this value to set the `total_fees` in the `Header`.

docs/docs/protocol-specs/gas-and-fees/published-gas-and-fee-data.md

@@ -12,6 +12,10 @@ The block header contains a `GlobalVariables`, which contains a `GasFees` object
 - `feePerDaGas`: The fee in [FPA](./fee-payment-asset.md) per unit of DA gas consumed for transactions in the block.
 - `feePerL2Gas`: The fee in FPA per unit of L2 gas consumed for transactions in the block.
 
+`GlobalVariables` also includes a `coinbase` field, which is the L1 address that receives the fees. 
+
+The block header also contains a `totalFees` field, which is the total fees collected in the block in FPA.
+
 ## Updating the `GasFees` Object
 
 Presently, the `feePerDaGas` and `feePerL2Gas` are fixed at `1` FPA per unit of DA gas and L2 gas consumed, respectively.

docs/docs/protocol-specs/gas-and-fees/specifying-gas-fee-info.md

@@ -78,10 +78,12 @@ These are held in the L2 blocks `Header`
 classDiagram
 class Header {
   +GlobalVariables globalVariables
+  +Fr totalFees
 }
 
 class GlobalVariables {
   +GasFees gasFees
+  +EthAddress coinbase
 }
 
 class GasFees {
@@ -97,6 +99,10 @@ A transaction cannot be executed if the `maxFeesPerGas` is less than the `feePer
 
 The `feePerGas` is presently held constant at `1` for both dimensions, but may be updated in future protocol versions.
 
+`totalFees` is the total fees collected in the block in FPA.
+
+`coinbase` is the L1 address that receives the fees.
+
 ## Transaction Fee
 
 The transaction fee is calculated as:

docs/docs/protocol-specs/rollup-circuits/base-rollup.md

@@ -56,6 +56,7 @@ class Header {
     content_commitment: ContentCommitment
     state: StateReference
     global_variables: GlobalVariables
+    total_fees: Fr
 }
 Header *.. Body : txs_hash
 Header *-- ContentCommitment: content_commitment

docs/docs/protocol-specs/rollup-circuits/index.md

@@ -188,6 +188,7 @@ class Header {
     content_commitment: ContentCommitment
     state: StateReference
     global_variables: GlobalVariables
+    total_fees: Fr
 }
 Header *.. Body : txs_hash
 Header *-- ContentCommitment: content_commitment

docs/docs/protocol-specs/rollup-circuits/root-rollup.md

@@ -56,6 +56,7 @@ class Header {
     content_commitment: ContentCommitment
     state: StateReference
     global_variables: GlobalVariables
+    total_fees: Fr
 }
 Header *.. Body : txs_hash
 Header *-- ContentCommitment: content_commitment

docs/docs/protocol-specs/state/archive.md

@@ -77,6 +77,7 @@ class Header {
     body_hash: Fr[2]
     state: StateReference
     global_variables: GlobalVariables
+    total_fees: Fr
 }
 Header *.. Body : body_hash
 Header *-- StateReference : state

docs/docs/protocol-specs/state/index.md

@@ -122,6 +122,7 @@ class Header {
     content_commitment: ContentCommitment
     state: StateReference
     global_variables: GlobalVariables
+    total_fees: Fr
 }
 Header *.. Body : txs_hash
 Header *-- ContentCommitment: content_commitment

l1-contracts/src/core/Rollup.sol

@@ -95,9 +95,9 @@ contract Rollup is IRollup {
       header.globalVariables.blockNumber, header.contentCommitment.outHash, l2ToL1TreeHeight
     );
 
-    // pay the coinbase 1 gas token if it is not empty
-    if (header.globalVariables.coinbase != address(0)) {
-      GAS_TOKEN.transfer(address(header.globalVariables.coinbase), 1);
+    // pay the coinbase 1 gas token if it is not empty and header.totalFees is not zero
+    if (header.globalVariables.coinbase != address(0) && header.totalFees > 0) {
+      GAS_TOKEN.transfer(address(header.globalVariables.coinbase), header.totalFees);
     }
 
     emit L2BlockProcessed(header.globalVariables.blockNumber);

l1-contracts/src/core/libraries/ConstantsGen.sol

@@ -140,8 +140,9 @@ library Constants {
     APPEND_ONLY_TREE_SNAPSHOT_LENGTH + PARTIAL_STATE_REFERENCE_LENGTH;
   uint256 internal constant TX_CONTEXT_LENGTH = 2 + GAS_SETTINGS_LENGTH;
   uint256 internal constant TX_REQUEST_LENGTH = 2 + TX_CONTEXT_LENGTH + FUNCTION_DATA_LENGTH;
+  uint256 internal constant TOTAL_FEES_LENGTH = 1;
   uint256 internal constant HEADER_LENGTH = APPEND_ONLY_TREE_SNAPSHOT_LENGTH
-    + CONTENT_COMMITMENT_LENGTH + STATE_REFERENCE_LENGTH + GLOBAL_VARIABLES_LENGTH;
+    + CONTENT_COMMITMENT_LENGTH + STATE_REFERENCE_LENGTH + GLOBAL_VARIABLES_LENGTH + TOTAL_FEES_LENGTH;
   uint256 internal constant PRIVATE_CIRCUIT_PUBLIC_INPUTS_LENGTH = CALL_CONTEXT_LENGTH + 4
     + MAX_BLOCK_NUMBER_LENGTH + (READ_REQUEST_LENGTH * MAX_NOTE_HASH_READ_REQUESTS_PER_CALL)
     + (READ_REQUEST_LENGTH * MAX_NULLIFIER_READ_REQUESTS_PER_CALL)
@@ -211,7 +212,7 @@ library Constants {
   uint256 internal constant CONSTANT_ROLLUP_DATA_LENGTH =
     APPEND_ONLY_TREE_SNAPSHOT_LENGTH + 4 + GLOBAL_VARIABLES_LENGTH;
   uint256 internal constant BASE_OR_MERGE_PUBLIC_INPUTS_LENGTH = CONSTANT_ROLLUP_DATA_LENGTH
-    + PARTIAL_STATE_REFERENCE_LENGTH + PARTIAL_STATE_REFERENCE_LENGTH + 4;
+    + PARTIAL_STATE_REFERENCE_LENGTH + PARTIAL_STATE_REFERENCE_LENGTH + 5;
   uint256 internal constant ENQUEUE_PUBLIC_FUNCTION_CALL_RETURN_LENGTH =
     2 + FUNCTION_DATA_LENGTH + CALL_CONTEXT_LENGTH;
   uint256 internal constant GET_NOTES_ORACLE_RETURN_LENGTH = 674;

l1-contracts/src/core/libraries/HeaderLib.sol

@@ -52,6 +52,7 @@ import {Hash} from "./Hash.sol";
  *  | 0x0208                                                                           | 0x20         |     gasFees.feePerL2Gas
  *  |                                                                                  |              |   }
  *  |                                                                                  |              | }
+ *  | 0x0228                                                                           | 0x20         | total_fees
  *  | ---                                                                              | ---          | ---
  */
 library HeaderLib {
@@ -100,9 +101,10 @@ library HeaderLib {
     ContentCommitment contentCommitment;
     StateReference stateReference;
     GlobalVariables globalVariables;
+    uint256 totalFees;
   }
 
-  uint256 private constant HEADER_LENGTH = 0x228; // Header byte length
+  uint256 private constant HEADER_LENGTH = 0x248; // Header byte length
 
   /**
    * @notice Validates the header
@@ -190,6 +192,9 @@ library HeaderLib {
     header.globalVariables.gasFees.feePerDaGas = uint256(bytes32(_header[0x01e8:0x0208]));
     header.globalVariables.gasFees.feePerL2Gas = uint256(bytes32(_header[0x0208:0x0228]));
 
+    // Reading totalFees
+    header.totalFees = uint256(bytes32(_header[0x0228:0x0248]));
+
     return header;
   }
 }

l1-contracts/test/fixtures/empty_block_0.json

@@ -8,7 +8,7 @@
     "l2ToL1Messages": []
   },
   "block": {
-    "archive": "0x0ed815d35918f1aabf391fa174a1d95476da157e40b7fc581b2c8f4cfd23e6b3",
+    "archive": "0x1457164d01299b0097706a5b0e8735720280e2937d369b2bee07ba987fd6846e",
     "body": "0x00000000",
     "txsEffectsHash": "0x002676dbd818b1ba16e11597cb5c07b06aa7771127b02a77d0c3a6039bb9fef1",
     "decodedHeader": {
@@ -23,16 +23,16 @@
         "chainId": 31337,
         "timestamp": 0,
         "version": 1,
-        "coinbase": "0xbe70f89d75a00bd140342ebc63beb517cf9735bc",
-        "feeRecipient": "0x08eb6120958820f4b4fd61a9bcaa32c33349663034e1db315ba57c67d155b172",
+        "coinbase": "0x13def1c0178621c029040272730bb660031f3d51",
+        "feeRecipient": "0x2193c536a292e81634f7f77e7c9f3fdc7a197d396bfda81fdc0112e0b2bc9bb6",
         "gasFees": {
           "feePerDaGas": 0,
           "feePerL2Gas": 0
         }
       },
       "lastArchive": {
         "nextAvailableLeafIndex": 1,
-        "root": "0x067a48e3140b6f15d71751ededfa0cccde3d436bb71aa7fec226b0bfe51dc5cf"
+        "root": "0x05b0b6df52f1d47d0406318558052c89a174fbc9d615def82b3cc9ccc1937db8"
       },
       "stateReference": {
         "l1ToL2MessageTree": {
@@ -55,8 +55,8 @@
         }
       }
     },
-    "header": "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",
-    "publicInputsHash": "0x00e9c95b88dbc49351e6a0a9b660918147d3c69410df4fba105c047a4f253a47",
+    "header": "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",
+    "publicInputsHash": "0x004fa9f8a995305c2569a378b91e45d14f9a6b7d9ba0ca19e0ac0e4ea79123fb",
     "numTxs": 0
   }
 }