From dd4e78b6bd746f210ab92d6b3e01db496c8a867e Mon Sep 17 00:00:00 2001
From: Drygin <DryginAlexander@gmail.com>
Date: Thu, 7 Apr 2022 23:17:21 +0300
Subject: [PATCH] add return list of inst to createInstanceClones()

---
 README.md                              |  4 ++--
 contracts/InstanceFactory.sol          | 12 ++++++------
 contracts/MultipleInstanceFactory.sol  |  6 ++++--
 test/multiple.instance.factory.test.js |  7 +++++++
 4 files changed, 19 insertions(+), 10 deletions(-)

diff --git a/README.md b/README.md
index 2463325..f20ffc0 100644
--- a/README.md
+++ b/README.md
@@ -61,8 +61,8 @@ Check config.js for actual values.
 
 With `salt` = `0x0000000000000000000000000000000000000000000000000000000047941987` address must be:
 
-1. `MultipleInstanceFactory` - `0xdacb0a030Bcfc7163922d34092a822cC19D12d40`
-2. `InstanceFactoryWithRegistry` - `0x6C1F437dFd70501Ad7f152897051446cc51F1eB6`
+1. `MultipleInstanceFactory` - `0x70A8e447E58480D68B56d88EF2C277Efe61e2b22`
+2. `InstanceFactoryWithRegistry` - `0xCAfb424689d3995c74a854e54cD24e2Be64C33D4`
 
 Check addresses with current config:
 
diff --git a/contracts/InstanceFactory.sol b/contracts/InstanceFactory.sol
index f3e5a80..03ac6d1 100644
--- a/contracts/InstanceFactory.sol
+++ b/contracts/InstanceFactory.sol
@@ -45,12 +45,12 @@ contract InstanceFactory is Ownable {
   function createInstanceClone(uint256 _denomination, address _token) public virtual returns (address) {
     bytes32 salt = keccak256(abi.encodePacked(_denomination, _token));
 
-    require(!implementation.predictDeterministicAddress(salt).isContract(), "Instance already exists");
-
-    address newClone = implementation.cloneDeterministic(salt);
-
-    emit NewInstanceCloneCreated(newClone);
-    ERC20TornadoCloneable(newClone).init(_denomination, merkleTreeHeight, _token);
+    address newClone = implementation.predictDeterministicAddress(salt);
+    if (!newClone.isContract()) {
+      implementation.cloneDeterministic(salt);
+      emit NewInstanceCloneCreated(newClone);
+      ERC20TornadoCloneable(newClone).init(_denomination, merkleTreeHeight, _token);
+    }
     return newClone;
   }
 
diff --git a/contracts/MultipleInstanceFactory.sol b/contracts/MultipleInstanceFactory.sol
index 645e682..04307e6 100644
--- a/contracts/MultipleInstanceFactory.sol
+++ b/contracts/MultipleInstanceFactory.sol
@@ -17,9 +17,11 @@ contract MultipleInstanceFactory is InstanceFactory {
    * @param _token address of ERC20 token for a new instance
    * @param _denominations list of denominations for each new instance
    */
-  function createInstanceClones(address _token, uint256[] memory _denominations) external {
+  function createInstanceClones(address _token, uint256[] memory _denominations) external returns (address[] memory) {
+    address[] memory newClones = new address[](_denominations.length);
     for (uint256 i = 0; i < _denominations.length; i++) {
-      createInstanceClone(_denominations[i], _token);
+      newClones[i] = createInstanceClone(_denominations[i], _token);
     }
+    return newClones;
   }
 }
diff --git a/test/multiple.instance.factory.test.js b/test/multiple.instance.factory.test.js
index 5e4a406..78f3be3 100644
--- a/test/multiple.instance.factory.test.js
+++ b/test/multiple.instance.factory.test.js
@@ -110,6 +110,13 @@ describe('Multiple Instance Factory Tests', () => {
     expect(await instance.hasher()).to.be.equal(config.hasher)
     expect(await instance.levels()).to.be.equal(config.merkleTreeHeight)
     expect(await instance.denomination()).to.equal(ethers.utils.parseEther('1000'))
+
+    // try to deploy the same instance again
+    await instanceFactory.connect(sender).createInstanceClone(ethers.utils.parseEther('1000'), config.COMP)
+
+    // check that instance has not been created - no new NewInstanceCloneCreated event
+    let curLogs = await instanceFactory.queryFilter('NewInstanceCloneCreated')
+    expect(curLogs.length).to.be.equal(logs.length)
   })
 
   it('Should successfully add instances', async function () {