feat[contracts]: temporarily disable EOA upgrades (#857)

* feat[contracts]: disable eoa upgrades temporarily

* chore: add changeset

* Update OVM_ProxyEOA.sol

* fix: turn upgrade into a noop

* lint: fix

.changeset/chatty-walls-rescue.md

+---
+'@eth-optimism/contracts': minor
+---
+
+Disables EOA contract upgrades until further notice

packages/contracts/contracts/optimistic-ethereum/OVM/accounts/OVM_ProxyEOA.sol

@@ -19,7 +19,7 @@ contract OVM_ProxyEOA {
     /**********
      * Events *
      **********/
-    
+
     event Upgraded(
         address indexed implementation
     );
@@ -71,13 +71,17 @@ contract OVM_ProxyEOA {
     )
         external
     {
-        require(
-            msg.sender == Lib_ExecutionManagerWrapper.ovmADDRESS(),
-            "EOAs can only upgrade their own EOA implementation"
-        );
+        // NOTE: Upgrades are temporarily disabled because users can, in theory, modify their EOA
+        // so that they don't have to pay any fees to the sequencer. Function will remain disabled
+        // until a robust solution is in place.
+
+        // require(
+        //     msg.sender == Lib_ExecutionManagerWrapper.ovmADDRESS(),
+        //     "EOAs can only upgrade their own EOA implementation"
+        // );
 
-        _setImplementation(_implementation);
-        emit Upgraded(_implementation);
+        // _setImplementation(_implementation);
+        // emit Upgraded(_implementation);
     }
 
     /**

packages/contracts/test/contracts/OVM/accounts/OVM_ProxyEOA.spec.ts

@@ -44,7 +44,9 @@ describe('OVM_ProxyEOA', () => {
     })
   })
 
-  describe('upgrade()', () => {
+  // NOTE: Upgrades are disabled for now but will be re-enabled at a later point in time. See
+  // comment in OVM_ProxyEOA.sol for additional information.
+  describe.skip('upgrade()', () => {
     it(`should upgrade the proxy implementation`, async () => {
       const newImpl = `0x${'81'.repeat(20)}`
       Mock__OVM_ExecutionManager.smocked.ovmADDRESS.will.return.with(