feat: remove migration code (#389)

### Description

fixes [L-1] Locking migration breaks withdrawals for unpaused MentoToken
by removing migration related code from locking contracts as we decided


### Other changes

no

### Tested

all tests pass

### Related issues

- Fixes #378

contracts/governance/locking/Locking.sol

@@ -2,7 +2,6 @@
 pragma solidity 0.8.18;
 // solhint-disable func-name-mixedcase
 
-import "./interfaces/INextVersionLock.sol";
 import "./LockingBase.sol";
 import "./LockingRelock.sol";
 import "./LockingVotes.sol";
@@ -53,20 +52,9 @@ contract Locking is ILocking, LockingBase, LockingRelock, LockingVotes {
     emit StartLocking(msg.sender);
   }
 
-  /**
-   * @notice Begins the migration process to a new contract
-   * @dev Can only be called by the owner
-   * @param to Address of the new contract where future operations will be migrated to
-   */
-  function startMigration(address to) external onlyOwner {
-    // slither-disable-next-line missing-zero-check
-    migrateTo = to;
-    emit StartMigration(msg.sender, to);
-  }
-
   /**
    * @notice Locks a specified amount of tokens for a given period
-   * @dev Can not be called when locking is stopped or migration is in progress
+   * @dev Can not be called when locking is stopped
    * @param account Account for which tokens are being locked
    * @param _delegate Address that will receive the voting power from the locked tokens
    * If address(0) passed, voting power will be lost
@@ -81,7 +69,7 @@ contract Locking is ILocking, LockingBase, LockingRelock, LockingVotes {
     uint96 amount,
     uint32 slopePeriod,
     uint32 cliff
-  ) external override notStopped notMigrating returns (uint256) {
+  ) external override notStopped returns (uint256) {
     require(amount > 0, "zero amount");
     require(cliff <= MAX_CLIFF_PERIOD, "cliff too big");
     require(slopePeriod <= MAX_SLOPE_PERIOD, "period too big");
@@ -164,7 +152,7 @@ contract Locking is ILocking, LockingBase, LockingRelock, LockingVotes {
    * @param id The unique identifier for the lock whose delegate is to be changed
    * @param newDelegate The address to which the delegation will be transferred
    */
-  function delegateTo(uint256 id, address newDelegate) external notStopped notMigrating {
+  function delegateTo(uint256 id, address newDelegate) external notStopped {
     address account = verifyLockOwner(id);
     address _delegate = locks[id].delegate;
     uint32 currentBlock = getBlockNumber();
@@ -205,45 +193,6 @@ contract Locking is ILocking, LockingBase, LockingRelock, LockingVotes {
     return accounts[account].balance.actualValue(time, currentBlock);
   }
 
-  /**
-   * @notice Migrates specified locks to a new contract
-   * @dev Performs the migration by transferring locked tokens and updating delegations as necessary
-   * @param id An array of lock IDs to be migrated
-   */
-  function migrate(uint256[] memory id) external {
-    if (migrateTo == address(0)) {
-      return;
-    }
-    uint32 currentBlock = getBlockNumber();
-    uint32 time = roundTimestamp(currentBlock);
-    INextVersionLock nextVersionLock = INextVersionLock(migrateTo);
-    for (uint256 i = 0; i < id.length; ++i) {
-      address account = verifyLockOwner(id[i]);
-      address _delegate = locks[id[i]].delegate;
-      updateLines(account, _delegate, time);
-      //save data Line before remove
-      LibBrokenLine.Line memory line = accounts[account].locked.initiatedLines[id[i]];
-      // slither-disable-start unused-return
-      (uint96 residue, , ) = accounts[account].locked.remove(id[i], time, currentBlock);
-
-      accounts[account].amount = accounts[account].amount - (residue);
-
-      accounts[_delegate].balance.remove(id[i], time, currentBlock);
-      totalSupplyLine.remove(id[i], time, currentBlock);
-      // slither-disable-end unused-return
-      // slither-disable-start reentrancy-no-eth
-      // slither-disable-start reentrancy-events
-      // slither-disable-start calls-loop
-      nextVersionLock.initiateData(id[i], line, account, _delegate);
-
-      require(token.transfer(migrateTo, residue), "transfer failed");
-      // slither-disable-end reentrancy-no-eth
-      // slither-disable-end reentrancy-events
-      // slither-disable-end calls-loop
-    }
-    emit Migrate(msg.sender, id);
-  }
-
   /**
    * @notice Returns the name of the token
    */

contracts/governance/locking/LockingBase.sol

@@ -44,10 +44,6 @@ abstract contract LockingBase is OwnableUpgradeable, IVotesUpgradeable {
    * @dev True if contract entered stopped state
    */
   bool public stopped;
-  /**
-   * @dev Address to migrate locks to. Is zero if not in migration state
-   */
-  address public migrateTo;
   /**
    * @dev Minimum cliff period in weeks
    */
@@ -125,10 +121,6 @@ abstract contract LockingBase is OwnableUpgradeable, IVotesUpgradeable {
    * @dev Emitted when withdraw amount of Rari, account - msg.sender, amount - amount Rari
    */
   event Withdraw(address indexed account, uint256 amount);
-  /**
-   * @dev Emitted when migrate Locks with given id, account - msg.sender
-   */
-  event Migrate(address indexed account, uint256[] id);
   /**
    * @dev Stop run contract functions, accept withdraw, account - msg.sender
    */
@@ -137,10 +129,6 @@ abstract contract LockingBase is OwnableUpgradeable, IVotesUpgradeable {
    * @dev Start run contract functions, accept withdraw, account - msg.sender
    */
   event StartLocking(address indexed account);
-  /**
-   * @dev StartMigration initiate migration to another contract, account - msg.sender, to - address delegate to
-   */
-  event StartMigration(address indexed account, address indexed to);
   /**
    * @dev set newMinCliffPeriod
    */
@@ -329,7 +317,7 @@ abstract contract LockingBase is OwnableUpgradeable, IVotesUpgradeable {
    * @notice Sets the starting point for the week-based time system
    * @param newStartingPointWeek new starting point
    */
-  function setStartingPointWeek(uint32 newStartingPointWeek) public notStopped notMigrating onlyOwner {
+  function setStartingPointWeek(uint32 newStartingPointWeek) public notStopped onlyOwner {
     require(newStartingPointWeek < roundTimestamp(getBlockNumber()), "wrong newStartingPointWeek");
     startingPointWeek = newStartingPointWeek;
 
@@ -340,7 +328,7 @@ abstract contract LockingBase is OwnableUpgradeable, IVotesUpgradeable {
    * @notice Sets the minimum cliff period
    * @param newMinCliffPeriod new minimum cliff period
    */
-  function setMinCliffPeriod(uint32 newMinCliffPeriod) external notStopped notMigrating onlyOwner {
+  function setMinCliffPeriod(uint32 newMinCliffPeriod) external notStopped onlyOwner {
     require(newMinCliffPeriod <= MAX_CLIFF_PERIOD, "new cliff period > 2 years");
     minCliffPeriod = newMinCliffPeriod;
 
@@ -351,7 +339,7 @@ abstract contract LockingBase is OwnableUpgradeable, IVotesUpgradeable {
    * @notice Sets the minimum slope period
    * @param newMinSlopePeriod new minimum slope period
    */
-  function setMinSlopePeriod(uint32 newMinSlopePeriod) external notStopped notMigrating onlyOwner {
+  function setMinSlopePeriod(uint32 newMinSlopePeriod) external notStopped onlyOwner {
     require(newMinSlopePeriod <= MAX_SLOPE_PERIOD, "new slope period > 2 years");
     minSlopePeriod = newMinSlopePeriod;
 
@@ -374,20 +362,12 @@ abstract contract LockingBase is OwnableUpgradeable, IVotesUpgradeable {
     _;
   }
 
-  /**
-   * @dev Throws if migration is active
-   */
-  modifier notMigrating() {
-    require(migrateTo == address(0), "migrating");
-    _;
-  }
-
   /**
    * @notice Updates the broken lines for an account until a given week number
    * @param account address of account to update
    * @param time week number until which to update lines
    */
-  function updateAccountLines(address account, uint32 time) public notStopped notMigrating onlyOwner {
+  function updateAccountLines(address account, uint32 time) public notStopped onlyOwner {
     accounts[account].balance.update(time);
     accounts[account].locked.update(time);
   }
@@ -396,7 +376,7 @@ abstract contract LockingBase is OwnableUpgradeable, IVotesUpgradeable {
    * @notice updates the total supply line until a given week number
    * @param time week number until which to update lines
    */
-  function updateTotalSupplyLine(uint32 time) public notStopped notMigrating onlyOwner {
+  function updateTotalSupplyLine(uint32 time) public notStopped onlyOwner {
     totalSupplyLine.update(time);
   }
 
@@ -405,12 +385,7 @@ abstract contract LockingBase is OwnableUpgradeable, IVotesUpgradeable {
    * @param account address of account to update
    * @param blockNumber block number until which to update lines
    */
-  function updateAccountLinesBlockNumber(address account, uint32 blockNumber)
-    external
-    notStopped
-    notMigrating
-    onlyOwner
-  {
+  function updateAccountLinesBlockNumber(address account, uint32 blockNumber) external notStopped onlyOwner {
     uint32 time = roundTimestamp(blockNumber);
     updateAccountLines(account, time);
   }
@@ -419,7 +394,7 @@ abstract contract LockingBase is OwnableUpgradeable, IVotesUpgradeable {
    * @notice Updates the total supply line until a given block number
    * @param blockNumber block number until which to update line
    */
-  function updateTotalSupplyLineBlockNumber(uint32 blockNumber) external notStopped notMigrating onlyOwner {
+  function updateTotalSupplyLineBlockNumber(uint32 blockNumber) external notStopped onlyOwner {
     uint32 time = roundTimestamp(blockNumber);
     updateTotalSupplyLine(time);
   }

contracts/governance/locking/LockingRelock.sol

@@ -24,7 +24,7 @@ abstract contract LockingRelock is LockingBase {
     uint96 newAmount,
     uint32 newSlopePeriod,
     uint32 newCliff
-  ) external notStopped notMigrating returns (uint256) {
+  ) external notStopped returns (uint256) {
     address account = verifyLockOwner(id);
     uint32 currentBlock = getBlockNumber();
     uint32 time = roundTimestamp(currentBlock);

test/governance/Locking/locking.t.sol

@@ -391,98 +391,6 @@ contract Lock_Locking_Test is Locking_Test {
     locking.getPastTotalSupply(currentBlock);
   }
 
-  function test_migrate_shouldMigrateLocks() public {
-    MockLocking mockLockingContract = new MockLocking();
-
-    mentoToken.mint(alice, 100000);
-    vm.prank(alice);
-    uint256 lockId = locking.lock(alice, alice, 60000, 30, 0);
-
-    uint256[] memory ids = new uint256[](1);
-    ids[0] = lockId;
-
-    vm.prank(owner);
-    locking.startMigration(address(mockLockingContract));
-    // (30 / 104) * 60000 = 17307
-    assertEq(locking.balanceOf(alice), 17307);
-    assertEq(locking.totalSupply(), 17307);
-
-    vm.prank(alice);
-    locking.migrate(ids);
-
-    assertEq(locking.balanceOf(alice), 0);
-    assertEq(locking.totalSupply(), 0);
-
-    assertEq(mentoToken.balanceOf(address(mockLockingContract)), 60000);
-    assertEq(locking.totalSupply(), 0);
-  }
-
-  function test_migrate_whenDelegatedAndInSlope_shouldMigrateLocks() public {
-    MockLocking newLockingContract = new MockLocking();
-
-    mentoToken.mint(alice, 100000);
-    vm.prank(alice);
-    uint256 lockId = locking.lock(alice, bob, 60000, 30, 0);
-
-    uint256[] memory ids = new uint256[](1);
-    ids[0] = lockId;
-
-    _incrementBlock(10 * weekInBlocks);
-
-    vm.prank(owner);
-    locking.startMigration(address(newLockingContract));
-
-    vm.prank(alice);
-    locking.migrate(ids);
-
-    assertEq(locking.balanceOf(bob), 0);
-    assertEq(mentoToken.balanceOf(address(locking)), 20000);
-    assertEq(mentoToken.balanceOf(address(newLockingContract)), 40000);
-    assertEq(mentoToken.balanceOf(alice), 40000);
-
-    assertEq(locking.totalSupply(), 0);
-
-    vm.prank(alice);
-    locking.withdraw();
-
-    assertEq(mentoToken.balanceOf(address(locking)), 0);
-    assertEq(locking.totalSupply(), 0);
-  }
-
-  function test_migrate_whenDelegatedAndInTail_shouldMigrateLocks() public {
-    MockLocking newLockingContract = new MockLocking();
-
-    mentoToken.mint(alice, 100);
-    vm.prank(alice);
-    uint256 lockId = locking.lock(alice, bob, 65, 11, 0);
-
-    uint256[] memory ids = new uint256[](1);
-    ids[0] = lockId;
-
-    _incrementBlock(10 * weekInBlocks);
-
-    vm.prank(owner);
-    locking.startMigration(address(newLockingContract));
-
-    vm.prank(alice);
-    locking.migrate(ids);
-
-    assertEq(mentoToken.balanceOf(address(locking)), 60);
-    assertEq(mentoToken.balanceOf(address(newLockingContract)), 5);
-    assertEq(mentoToken.balanceOf(alice), 35);
-
-    vm.prank(alice);
-    locking.withdraw();
-    assertEq(mentoToken.balanceOf(address(locking)), 0);
-    assertEq(mentoToken.balanceOf(address(newLockingContract)), 5);
-    assertEq(mentoToken.balanceOf(alice), 95);
-  }
-
-  function test_startMigration_whenNotOwner_shouldRevert() public {
-    vm.expectRevert("Ownable: caller is not the owner");
-    locking.startMigration(address(1));
-  }
-
   function test_setMinCliffPeriod_setMinSlope_whenNotOwner_shouldRevert() public {
     vm.expectRevert("Ownable: caller is not the owner");
     locking.setMinCliffPeriod(3);