add permissionless lending features #634

KevinMomanyi · 2025-03-22T09:33:13Z

#Description of my work
I have implemented the followings in the contract system;

Permissionless deployment of new lending pools through a factory contract
Automatic registration of newly deployed pools with the global ledger
Role-based access control to ensure only registered pools can interact with the global ledger

Closes #613

gitshreevatsa

Thanks for opening the PR. There are some things to be addressed:

Cross shard deployment of Lending pool is not supported in this model. Please go through this for understanding how to deploy to different shards
One of the acceptance criteria was to not change existing functionality but the code introduced here, has empty functions.
There is a deadlock between constructor of global ledger contract and lending pool factory contract, according to the current implementation introduced I would need global ledger to deploy the factory but to deploy the factory I need the global ledger as well, which is not possible.

Please address these and let us know if you have any issues on implementing the given functionalities.

Also, please mention the issue you are solving, by linking it to this PR.

KevinMomanyi · 2025-03-27T13:33:54Z

hello @gitshreevatsa thanks for your update on some of things I need to address on my issue assigned. I have already made the changes to reflect your guidance and the things we need to address as follows;
Feature requirements;
✅ Factory-Based Pool Deployment – user can deploy a new lending pool with a specified token.
✅ Automatic Global Ledger Registration – Each deployed pool gets registered with the GlobalLedger contract.
✅ Role-Based Access Control – Only registered pools can interact with ledger functions.
✅ Support for Custom Tokens – Each lending pool supports a unique token.

gitshreevatsa

Please review the changes mentioned

gitshreevatsa · 2025-03-27T16:41:19Z

academy/lending-protocol/contracts/GlobalLedger.sol

+import "@nilfoundation/smart-contracts/contracts/NilTokenBase.sol";
+
+// Axelar Gateway Interface for cross-chain communication
+interface IAxelarGateway {


I don't think axelar gateway is something that works over here. As we support our own inter shard communication system. I would prefer you to go through our docs of cross shard communication: here

You would have to deploy a lending pool using the asyncDeploy and then call a registration function.

gitshreevatsa · 2025-03-27T16:42:07Z

academy/lending-protocol/contracts/GlobalLedger.sol

+        address gateway,
+        address token
+    ) external returns (address) {
+        LendingPool newPool = new LendingPool(globalLedger, lendingPoolChain, gateway, msg.sender, token);


This method wouldn't work if the contracts are deployed on different shards

gitshreevatsa · 2025-03-27T16:43:19Z

academy/lending-protocol/contracts/GlobalLedger.sol

+        token = _token;
+    }
+
+    function deposit(uint256 amount) external {


I see that you have changed the deposit function such that it is not backward compatible. One of the main criterias is to make sure backward compatiblity, these changes don't let the interaction remain same.

KevinMomanyi · 2025-03-27T23:49:03Z

hello @gitshreevatsa, the changes you suggested have already made in the code such as using the default inter shard communication system, deploy a lending pool using the asyncDeploy and then call a registration function and also backward compatibility. hope this will function, thanks.

gitshreevatsa

Thanks for some changes, I have left some comments to align on completing this issue.

gitshreevatsa · 2025-03-28T06:30:25Z

academy/lending-protocol/contracts/LendingPoolFactory.sol

+    }
+
+    function deployLendingPool() external returns (address) {
+        LendingPool newPool = new LendingPool(


As mentioned previously, this method would just deploy on the same shard but not on other shards. The requirement is to use asyncDeploy and deploy into other shards based on a round robin fashion, have a counter which doesn't exceed 4 and on every deployment it increments so that you have deploy onto different shards.

gitshreevatsa · 2025-03-28T06:31:48Z

academy/lending-protocol/contracts/LendingPoolFactory.sol

+        address poolAddress = address(newPool);
+
+        // Asynchronously register the new lending pool with the GlobalLedger
+        globalLedger.asyncCall(


I doubt this is the signature of asyncCall. You can see the signature here

gitshreevatsa · 2025-03-28T06:38:32Z

academy/lending-protocol/contracts/LendingPool.sol

@@ -5,22 +5,15 @@ import "@nilfoundation/smart-contracts/contracts/Nil.sol";
 import "@nilfoundation/smart-contracts/contracts/NilTokenBase.sol";

 /// @title LendingPool
-/// @dev The LendingPool contract facilitates lending and borrowing of tokens and handles collateral management.
-/// It interacts with other contracts such as GlobalLedger, InterestManager, and Oracle for tracking deposits, calculating interest, and fetching token prices.
+/// @dev A contract for decentralized lending and borrowing, integrating GlobalLedger, InterestManager, and Oracle.


This contracts still lacks repayment so it wouldn't support backward compatiblity, please add the repayment functions that are associated. They are currently present in the academy.

gitshreevatsa · 2025-03-28T06:39:37Z

academy/lending-protocol/contracts/GlobalLedger.sol

+}
+
+/// @title LendingPool - Individual lending pools for decentralized lending
+contract LendingPool {


Why is the extra contract written here when there is already LendingPool.sol in another file. And moreover this contracts lacks a lot of funtionalities. This seems extra contract. You can remove this

gitshreevatsa · 2025-03-28T06:41:07Z

academy/lending-protocol/contracts/GlobalLedger.sol

+        return userDeposits[user];
+    }
+
+    function deployLendingPool() external {


I am confused why does the GlobalLedger have deployLendingPool function while it had to be the Factory contract that should have this. Please explain me the arcitecutre that you intend to build, it would be of good discussion to know your thoughts!

KevinMomanyi · 2025-03-28T13:07:14Z

Hi @gitshreevatsa I have made some changes to align with the guidance you recommended;
my Architecture Summary includes;
LendingPoolFactory.sol - Handles pool deployment across shards.
LendingPool.sol - Handles deposits, loans, and interactions with GlobalLedger.
GlobalLedger.sol - Only tracks deposits, loans, and repayments.

academy/lending-protocol/package-lock.json

academy/lending-protocol/package.json

gitshreevatsa

Thanks for making some changes from previous comments. I think the issue requires these steps:

Don't change anything with respect to LendingPool contract(currently in the nil repository, the forked repository has some changes).
After asyncDeploy in the LendingPool Factory contract, please add a asyncCall to the GlobalLedger.
Change the GlobalLedger to have a role based access function in which only the factory can set the lending pool address and then use that modifier for recordLoan, recordDeposit and recordRepay
Also, please create a new Hardhat Task for testing, it would be easier to test.

gitshreevatsa · 2025-04-01T13:50:26Z

academy/lending-protocol/contracts/GlobalLedger.sol

+
+// @title GlobalLedger
+// @dev Tracks deposits, loans, and repayments across LendingPool contracts
+contract GlobalLedger {


While there already exists CollateralManager contract, why would we need this GlobalLedger Contract?

gitshreevatsa · 2025-04-01T13:51:35Z

academy/lending-protocol/contracts/LendingPool.sol

-    /// @param success Indicates if the loan clearing was successful.
-    /// @param returnData The collateral data returned from the GlobalLedger.
-    /// @param context The context containing borrower and collateral token.
-    function releaseCollateral(


Without these functions, thee=re would be no colateral release, please dont change them

gitshreevatsa · 2025-04-01T13:52:34Z

academy/lending-protocol/contracts/LendingPoolFactory.sol

+    }
+
+    /// @notice Deploys a new LendingPool contract to a shard
+    function deployLendingPool() external {


With the deployment of the contract, there should be a function which calls the globalLedger to register the lending pool

well noted Sir, I will make changes

KevinMomanyi · 2025-04-04T00:47:52Z

Hello @gitshreevatsa, hope you are well. The cha nges you requested have made some effort to ensure the project fuction smoothly.Below are the changes made;
1. No changes to LendingPool contract
You mentioned that the LendingPool contract should remain untouched as per the canonical version in the nil repo and this has been respected.
2. asyncCall to the GlobalLedger after asyncDeploy in the LendingPoolFactory
The LendingPoolFactory now performs an asyncDeploy for a new lending pool and follows it up with an asyncCall to GlobalLedger.registerLendingPool(address) using the new pool's address.This satisfies the requirement to automatically register the deployed pool with the ledger.
3. Role-based access in GlobalLedger
The GlobalLedger contract:
Inherits from Ownable (factory = owner).
Allows only the factory (owner) to register new lending pools.
Uses a modifier onlyLendingPool to restrict access to recordLoan, recordDeposit, and repayLoan. This meets the requirement of factory-controlled access for authorized lending pools.
4. Hardhat task for deployment/testing
There is now a custom Hardhat task for testing. This makes it much easier to test end-to-end deployment.

Kind regards.

gitshreevatsa

Thank you for making these changes, there are a few things to address and things are going forward!

gitshreevatsa · 2025-04-04T07:18:14Z

academy/lending-protocol/contracts/LendingPoolFactory.sol

+        shardCounter = (shardCounter + 1) % 4; // Cycle through shards
+
+        // Async call to register LendingPool in GlobalLedger
+        (bool success, ) = globalLedger.call(


The call has to be made via asyncCall because when the global ledger is on different shard compared to the shard where Factory is deployed, this call would fail to work. Just include Nil.asyncCall and no need to resolve it!

gitshreevatsa · 2025-04-04T07:19:38Z

academy/lending-protocol/task/deployLendingPool.js

@@ -0,0 +1,42 @@
+const { task } = require("hardhat/config");
+
+task("deploy-lending-pool", "Deploys a new LendingPool contract and registers it in GlobalLedger")


Please check the run-lending-protocol task, in that you can see that the contracts are in fact deployed rather than taken from the params.

gitshreevatsa · 2025-04-04T07:20:50Z

academy/lending-protocol/task/deployLendingPool.js

+    const factory = LendingPoolFactory.attach(factoryAddress);
+
+    // Deploy LendingPool via factory
+    const tx = await factory.deployLendingPool();


Usage of ethers wouldn't work completely with =nil; as we have some differences while calling contracts. Please use niljs. You can learn more about niljs here.

gitshreevatsa · 2025-04-04T07:24:10Z

academy/lending-protocol/contracts/GlobalLedger.sol

+
+/// @title GlobalLedger
+/// @dev Tracks deposits, loans, and repayments across LendingPool contracts
+contract GlobalLedger is Ownable {


While we already have the GlobalLedger inside CollateralManager.sol why did you want to write an amended contract? I would advise you to use the GlobalLedger inside CollateralManager.sol as it has a lot of functionality that would support backward compatiblity. So only thing you would have to change in GlobalLedger inside CollateralManager.sol would be add factory based role access to it, as your code for factory based role access looks good.

Hello @gitshreevatsa, thanks for the update. I have made some changes on the code incuding removing Globalledger.sol to avoid duplicate and others.

gitshreevatsa

Please address the changes mentioned.

gitshreevatsa · 2025-04-05T10:04:01Z

academy/lending-protocol/contracts/LendingPoolFactory.sol

+
+        // Assuming Nil provides an alternative method for cross-shard calls
+        // Using Nil.asyncCall to interact with GlobalLedger
+        (bool success, ) = address(Nil).call(


Please change this to use Nil.asyncCall with the correct signature

gitshreevatsa · 2025-04-05T10:05:04Z

academy/lending-protocol/task/deployLendingPool.js

+const { task } = require("hardhat/config");
+const { Nil } = require("niljs");
+
+task("deploy-lending-pool", "Deploys a new LendingPool and registers in GlobalLedger")


The contracts have to deployed inside the task and not be taken as arguments of the script.

gitshreevatsa · 2025-04-05T10:06:44Z

academy/lending-protocol/task/deployLendingPool.js

+      eth,
+    } = taskArgs;
+
+    const nil = new Nil(hre.network.config.nilProviderUrl); // configure `nilProviderUrl` in hardhat.config.ts


Can you please go through run-lending-pool task file once to see how a client is initiated, how a smart contract/account is deployed and how transactions are sent to the network. This implementation wouldn't work.

…action

KevinMomanyi · 2025-04-05T22:20:02Z

hello @gitshreevatsa , some changes made as guided. Thanks

gitshreevatsa

Please address the comments mentioned. Thank you for making previous changes.

gitshreevatsa · 2025-04-07T10:47:44Z

academy/lending-protocol/task/deployLendingPool.ts

+  FaucetClient,
+  generateSmartAccount,
+  waitTillCompleted,
+  Contract,


There is no class named Contract that is exposed in niljs

gitshreevatsa · 2025-04-07T10:48:45Z

academy/lending-protocol/contracts/LendingPoolFactory.sol

+
+        // Cross-shard async call to GlobalLedger to register the new LendingPool
+        Nil.asyncCall(
+            0, // Shard ID for GlobalLedger


A contract cannot be deployed on shard 0. Please change this to the respective shard id of global ledger that you deploy in the script

gitshreevatsa · 2025-04-07T10:50:33Z

academy/lending-protocol/test/FactoryLendingPool.test.ts

+    [deployer, user] = await ethers.getSigners();
+
+    // Deploy LendingPoolFactory contract
+    const LendingPoolFactory = await ethers.getContractFactory("LendingPoolFactory");


You would have to use niljs as I had previously mentioned.

gitshreevatsa · 2025-04-07T10:51:29Z

academy/lending-protocol/task/deployLendingPool.ts

+  console.log(`Oracle deployed: ${oracle}`);
+
+  // Step 3: Deploy LendingPool with linked contracts
+  const { address: lendingPool, hash: lendingPoolHash } = await deployer.deployContract({


You have to deploy the lending pool via the factory not via a separate script

Well noted Sir. Thanks

Good Afternoon @gitshreevatsa,
The changes you guided from my code have tried to address it, am requesting if you can check on it. Thanks.

…nd test scripts

gitshreevatsa

Thank you for implementing the changes. Please address these comments

gitshreevatsa · 2025-04-09T14:03:32Z

academy/lending-protocol/contracts/LendingPoolFactory.sol

+            constructorArgs
+        );
+
+        address poolAddress = INilAsync(NIL_ASYNC_PRECOMPILE).asyncDeploy(


You can directly use Nil.sol than creating an interface. Please use that

gitshreevatsa · 2025-04-09T14:05:12Z

academy/lending-protocol/task/deployLendingPool.ts

+    args: [],
+  });
+
+  const { hash: deployHash } = await deployer.execute({


This would be deloyer.sendTransaction not execute

Hello @gitshreevatsa ,
I have address the changes requested, thanks.

…ransaction handling

gitshreevatsa

Thank you for making changes. Please address the issues with respect to Factory contract and the file structures.

gitshreevatsa · 2025-04-18T09:34:52Z

academy/lending-protocol/contracts/LendingPoolFactory.sol

+    uint8 public shardCounter;
+
+    /// @dev Nil precompile interface for async deploy/call
+    Nil constant nil = Nil(0x0000000000000000000000000000000000008003);


You dont need to do this. Nil.sol directly gives you access to asyncCall or asyncDeploy

gitshreevatsa · 2025-04-18T09:37:36Z

academy/lending-protocol/contracts/LendingPoolFactory.sol

+            0
+        );
+
+        require(success, "asyncCall to GlobalLedger failed");


You dont get a response back from asyncCall precompile

gitshreevatsa · 2025-04-18T09:37:55Z

academy/lending-protocol/contracts/tsconfig.json

@@ -0,0 +1,113 @@
+{


Why is this file present inside comtracts?

gitshreevatsa · 2025-04-18T09:40:37Z

academy/lending-protocol/contracts/LendingPoolFactory.sol

+            0,
+            0,
+            bytecode,
+            0


Generally the salt argument shouldn,t be set 0. You can instead use a counter

Thanks @gitshreevatsa for your feedback ,
I have address the issues with respect to Factory contract and the file structures.

add permissionless lending features

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add missing functionalities to the code

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Fix: Remove asyncCall return check in LendingPoolFactory

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		@@ -0,0 +1,42 @@
		const { task } = require("hardhat/config");

		task("deploy-lending-pool", "Deploys a new LendingPool contract and registers it in GlobalLedger")

add permissionless lending features #634

Are you sure you want to change the base?

add permissionless lending features #634

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KevinMomanyi commented Mar 22, 2025 •

edited by gitshreevatsa

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