feat: revert if timestamp in future

l1-contracts/src/core/Rollup.sol

@@ -444,31 +444,10 @@ contract Rollup is Leonidas, IRollup, ITestRollup {
     uint256 _currentTime,
     DataStructures.ExecutionFlags memory _flags
   ) external view override(IRollup) {
-    // @note  This is a convenience function to allow for easier testing of the header validation
-    //        without having to go through the entire process of submitting a block.
-    //        This is not used in production code.
-
     HeaderLib.Header memory header = HeaderLib.decode(_header);
     _validateHeader(header, _signatures, _digest, _currentTime, _flags);
   }
 
-  function _validateHeader(
-    HeaderLib.Header memory _header,
-    SignatureLib.Signature[] memory _signatures,
-    bytes32 _digest,
-    uint256 _currentTime,
-    DataStructures.ExecutionFlags memory _flags
-  ) internal view {
-    // @note  This is a convenience function to allow for easier testing of the header validation
-    //        without having to go through the entire process of submitting a block.
-    //        This is not used in production code.
-
-    _validateHeaderForSubmissionBase(_header, _currentTime, _flags);
-    _validateHeaderForSubmissionSequencerSelection(
-      _header.globalVariables.slotNumber, _signatures, _digest, _currentTime, _flags
-    );
-  }
-
   /**
    * @notice Processes an incoming L2 block with signatures
    *
@@ -589,6 +568,29 @@ contract Rollup is Leonidas, IRollup, ITestRollup {
     }
   }
 
+  /**
+   * @notice  Validates the header for submission
+   *
+   * @param _header - The proposed block header
+   * @param _signatures - The signatures for the attestations
+   * @param _digest - The digest that signatures signed
+   * @param _currentTime - The time of execution
+   * @dev                - This value is provided to allow for simple simulation of future
+   * @param _flags - Flags specific to the execution, whether certain checks should be skipped
+   */
+  function _validateHeader(
+    HeaderLib.Header memory _header,
+    SignatureLib.Signature[] memory _signatures,
+    bytes32 _digest,
+    uint256 _currentTime,
+    DataStructures.ExecutionFlags memory _flags
+  ) internal view {
+    _validateHeaderForSubmissionBase(_header, _currentTime, _flags);
+    _validateHeaderForSubmissionSequencerSelection(
+      _header.globalVariables.slotNumber, _signatures, _digest, _currentTime, _flags
+    );
+  }
+
   /**
    * @notice  Validate a header for submission to the pending chain (sequencer selection checks)
    *
@@ -703,6 +705,16 @@ contract Rollup is Leonidas, IRollup, ITestRollup {
       revert Errors.Rollup__InvalidTimestamp(timestamp, _header.globalVariables.timestamp);
     }
 
+    if (timestamp > _currentTime) {
+      // @note  If you are hitting this error, it is likely because the chain you use have a blocktime that differs
+      //        from the value that we have in the constants.
+      //        When you are encountering this, it will likely be as the sequencer expects to be able to include
+      //        an Aztec block in the "next" ethereum block based on a timestamp that is 12 seconds in the future
+      //        from the last block. However, if the actual will only be 1 second in the future, you will end up
+      //        expecting this value to be in the future.
+      revert Errors.Rollup__TimestampInFuture(_currentTime, timestamp);
+    }
+
     // Check if the data is available using availability oracle (change availability oracle if you want a different DA layer)
     if (
       !_flags.ignoreDA && !AVAILABILITY_ORACLE.isAvailable(_header.contentCommitment.txsEffectsHash)

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

@@ -56,7 +56,7 @@ library Errors {
   error Rollup__InvalidChainId(uint256 expected, uint256 actual); // 0x37b5bc12
   error Rollup__InvalidVersion(uint256 expected, uint256 actual); // 0x9ef30794
   error Rollup__InvalidTimestamp(uint256 expected, uint256 actual); // 0x3132e895
-  error Rollup__TimestampInFuture(); // 0xbc1ce916
+  error Rollup__TimestampInFuture(uint256 max, uint256 actual); // 0x89f30690
   error Rollup__TimestampTooOld(); // 0x72ed9c81
   error Rollup__UnavailableTxs(bytes32 txsHash); // 0x414906c3
   error Rollup__NothingToPrune(); // 0x850defd3

l1-contracts/test/Rollup.t.sol

@@ -78,6 +78,19 @@ contract RollupTest is DecoderBase {
     _;
   }
 
+  function testTimestamp() public setUpFor("mixed_block_1") {
+    // Ensure that the timestamp of the current slot is never in the future.
+    for (uint256 i = 0; i < 100; i++) {
+      uint256 slot = rollup.getCurrentSlot();
+      uint256 ts = rollup.getTimestampForSlot(slot);
+
+      assertLe(ts, block.timestamp, "Invalid timestamp");
+
+      vm.warp(block.timestamp + 12);
+      vm.roll(block.number + 1);
+    }
+  }
+
   function testRevertPrune() public setUpFor("mixed_block_1") {
     if (rollup.isDevNet()) {
       vm.expectRevert(abi.encodeWithSelector(Errors.DevNet__NoPruningAllowed.selector));
@@ -182,6 +195,9 @@ contract RollupTest is DecoderBase {
 
     uint256 portalBalance = portalERC20.balanceOf(address(feeJuicePortal));
 
+    // We jump to the time of the block. (unless it is in the past)
+    vm.warp(max(block.timestamp, data.decodedHeader.globalVariables.timestamp));
+
     vm.expectRevert(
       abi.encodeWithSelector(
         IERC20Errors.ERC20InsufficientBalance.selector,