Remove unnecessary back and forth transfers in IexecPoco2Delegate

Author: james-toussaint

CHANGELOG.md

@@ -1,6 +1,12 @@
 # Changelog
 
 ## vNEXT
+
+### Updated contracts
+- [x] `IexecPoco2Delegate.sol`
+
+### Features
+- Remove unnecessary back and forth transfers in `IexecPoco2Delegate` happening during `claim(..)`. (#167)
 - Remove references to blockscout v5. (#161)
 - Migrate integration test files to Typescript & Hardhat:
     - 000_fullchain.js (#156, #157)

contracts/modules/delegates/IexecPoco2Delegate.sol

@@ -61,8 +61,15 @@ contract IexecPoco2Delegate is IexecPoco2, DelegateBase, IexecEscrow, SignatureV
 
         unlock(deal.sponsor, taskPrice); // Refund the payer of the task
         seize(deal.workerpool.owner, poolstake, _taskid);
-        reward(KITTY_ADDRESS, poolstake, _taskid); // → Kitty / Burn
-        lock(KITTY_ADDRESS, poolstake); // → Kitty / Burn
+        /**
+         * Reward kitty and lock value on it.
+         * Next lines optimize simple `reward(kitty, ..)` and `lock(kitty, ..)` calls
+         * where functions would together uselessly transfer value from main PoCo
+         * proxy to kitty, then would transfer value back from kitty to main PoCo proxy.
+         */
+        m_frozens[KITTY_ADDRESS] += poolstake; // → Kitty / Burn
+        emit Reward(KITTY_ADDRESS, poolstake, _taskid);
+        emit Lock(KITTY_ADDRESS, poolstake);
     }
 
     /***************************************************************************

test/byContract/IexecPoco/06_claim.test.ts

@@ -144,12 +144,8 @@ describe('IexecPoco2#claim', async () => {
             .withArgs(sponsor.address, taskPrice)
             .to.emit(iexecPoco, 'Seize')
             .withArgs(scheduler.address, schedulerTaskStake, taskId)
-            .to.emit(iexecPoco, 'Transfer')
-            .withArgs(iexecPoco.address, kittyAddress, schedulerTaskStake)
             .to.emit(iexecPoco, 'Reward')
             .withArgs(kittyAddress, schedulerTaskStake, taskId)
-            .to.emit(iexecPoco, 'Transfer')
-            .withArgs(kittyAddress, iexecPoco.address, schedulerTaskStake)
             .to.emit(iexecPoco, 'Lock')
             .withArgs(kittyAddress, schedulerTaskStake);
         for (const worker of workers) {