remove pseudo transfer event

Author: d10r

packages/ethereum-contracts/CHANGELOG.md

@@ -15,7 +15,6 @@ This project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.htm
   - `GDAv1StorageWriter` contains functions for writing agreement data to the token contract. This can only be used by the GDA contract itself.
 - bump solc to "0.8.30".
 - Changed EVM target from `paris` to `shanghai` because now all networks with supported Superfluid deployment support it.
-- Emit ERC20 `Transfer` events (with amount 0) on CFA and GDA actions potentially leading to account balance changes. This shall help indexers to keep track of SuperToken holders and account balances.
 - Don't emit ERC20 `Approval` events on `transferFrom` operations. This is consistent with the OpenZeppelin ERC20 implementation from v5 onwards. Change effective only for SuperTokens using the latest logic.
 
 ### Fixed

packages/ethereum-contracts/contracts/agreements/ConstantFlowAgreementV1.sol

@@ -453,11 +453,6 @@ contract ConstantFlowAgreementV1 is
                 ctx, currentContext);
         }
 
-        // solhint-disable-next-line no-empty-blocks
-        try flowVars.token.emitPseudoTransfer(flowVars.sender, flowVars.receiver) {}
-        // solhint-disable-next-line no-empty-blocks
-        catch {}
-
         _requireAvailableBalance(flowVars.token, flowVars.sender, currentContext);
     }
 
@@ -598,10 +593,6 @@ contract ConstantFlowAgreementV1 is
             }
         }
 
-        // solhint-disable-next-line no-empty-blocks
-        try flowVars.token.emitPseudoTransfer(flowVars.sender, flowVars.receiver) {}
-        // solhint-disable-next-line no-empty-blocks
-        catch {}
     }
 
     /**************************************************************************

packages/ethereum-contracts/contracts/agreements/gdav1/GeneralDistributionAgreementV1.sol

@@ -830,16 +830,6 @@ contract GeneralDistributionAgreementV1 is AgreementBase, TokenMonad, IGeneralDi
         return true;
     }
 
-    function tokenEmitPseudoTransfer(ISuperfluidToken superToken, address from, address to)
-        external
-        senderIsTrustedPool(superToken)
-    {
-        // solhint-disable-next-line no-empty-blocks
-        try superToken.emitPseudoTransfer(from, to) {}
-        // solhint-disable-next-line no-empty-blocks
-        catch {}
-    }
-
     //////////////////////////////////////////////////////////////////////////////////////////////////////
     // TokenMonad interface
     //////////////////////////////////////////////////////////////////////////////////////////////////////

packages/ethereum-contracts/contracts/agreements/gdav1/SuperfluidPool.sol

@@ -454,10 +454,6 @@ contract SuperfluidPool is ISuperfluidPool, BeaconProxiable {
             assert(GDA.appendIndexUpdateByPool(superToken, p, t));
         }
 
-        if ((oldUnits == 0 || newUnits == 0) && oldUnits != newUnits) {
-            GDA.tokenEmitPseudoTransfer(superToken, address(this), memberAddr);
-        }
-
         emit MemberUnitsUpdated(superToken, memberAddr, oldUnits, newUnits);
     }
 

packages/ethereum-contracts/contracts/interfaces/superfluid/ISuperfluidToken.sol

@@ -431,11 +431,4 @@ interface ISuperfluidToken {
         uint256 rewardAmount,
         uint256 bailoutAmount
     );
-
-    /**
-     * @dev Emit an ERC20.Transfer event with zero amount, helps indexers track token holders.
-     * @param from The address from which the transfer is happening
-     * @param to The address to which the transfer is happening
-     */
-    function emitPseudoTransfer(address from, address to) external;
 }

packages/ethereum-contracts/contracts/superfluid/SuperfluidToken.sol

@@ -376,10 +376,6 @@ abstract contract SuperfluidToken is ISuperfluidToken
         );
     }
 
-    function emitPseudoTransfer(address from, address to) external onlyAgreement {
-        emit IERC20.Transfer(from, to, 0);
-    }
-
     /**************************************************************************
     * Modifiers
     *************************************************************************/

packages/ethereum-contracts/test/foundry/superfluid/SuperToken.t.sol

@@ -259,54 +259,4 @@ contract SuperTokenIntegrationTest is FoundrySuperfluidTester {
         assertEq(localSuperToken.nonces(permitSigner), 1, "Nonce should be incremented");
         assertEq(localSuperToken.allowance(permitSigner, spender), amount, "Allowance should be set");
     }
-
-    // Verify zero Transfer events being emitted by CFA and GDA actions
-    function testEmitPseudoTransferEvent() public {
-        vm.startPrank(admin);
-
-        // case 1: create flow
-        vm.expectEmit(address(superToken));
-        emit IERC20.Transfer(admin, alice, 0);
-        superToken.createFlow(alice, 1);
-
-        // case 2: delete flow
-        vm.expectEmit(address(superToken));
-        emit IERC20.Transfer(admin, alice, 0);
-        superToken.deleteFlow(admin, alice);
-
-        // create a pool for the next tests
-        ISuperfluidPool pool = superToken.createPool(
-            admin,
-            PoolConfig({
-                transferabilityForUnitsOwner: true,
-                distributionFromAnyAddress: true
-            })
-        );
-
-        // case 3: assign pool units
-        vm.expectEmit(address(superToken));
-        emit IERC20.Transfer(address(pool), alice, 0);
-        pool.updateMemberUnits(alice, 1);
-
-        vm.stopPrank();
-
-        // case 4: test pool token transfer
-        vm.startPrank(alice);
-        // This emits 2 Transfer events, because the sender's units toggle to 0 and the receiver units from 0
-        vm.expectEmit(address(superToken));
-        emit IERC20.Transfer(address(pool), alice, 0);
-        vm.expectEmit(address(superToken));
-        emit IERC20.Transfer(address(pool), bob, 0);
-        IERC20(pool).transfer(bob, 1);
-
-        vm.stopPrank();
-
-        // case 5: remove pool units
-        vm.startPrank(admin);
-        vm.expectEmit(address(superToken));
-        emit IERC20.Transfer(address(pool), bob, 0);
-        pool.updateMemberUnits(bob, 0);
-
-        vm.stopPrank();
-    }
 }