feat(rln)!: generate contract types, migrate from ethers to viem #2705

adklempner · 2025-10-24T22:42:06Z

Problem / Description

Previous to this, the ABIs for the contracts were manually added to the rln package (not clear how).
Additionally, code related to calling the contracts was not typed, so any breaking changes to the ABI would not be detected at compile time.

Solution

Create a script that:

cloneshttps://github.com/waku-org/waku-rlnv2-contract
compiles it
uses the output to generate typesafe ABI code using wagmi

The rest of the code has been updated to use viem, which provides clean and typesafe ways to interact with the smart contracts.

Also adds new methods that were introduced in latest contract changes, specifically the ability to query for merkle root and merkle proof for a commitment directly from the smart contract.

Notes

Resolves feat(rln): replace manual smart contract classes/functions with generate typings #2630
Dogfooding PR: feat: use viem instead of ethers rln.waku.org#20

Checklist

Code changes are covered by unit tests.
Code changes are covered by e2e tests, if applicable.
Dogfooding has been performed, if feasible.
A test version has been published, if required.
All CI checks pass successfully.

github-actions · 2025-10-24T22:48:12Z

size-limit report 📦

Path	Size	Loading time (3g)	Running time (snapdragon)	Total time
Waku node	96.31 KB (0%)	2 s (0%)	669 ms (-31.94% 🔽)	2.6 s
Waku Simple Light Node	147.49 KB (0%)	3 s (0%)	669 ms (-4.67% 🔽)	3.7 s
ECIES encryption	22.62 KB (0%)	453 ms (0%)	372 ms (+80.18% 🔺)	825 ms
Symmetric encryption	22 KB (0%)	440 ms (0%)	271 ms (+66.13% 🔺)	711 ms
DNS discovery	52.17 KB (0%)	1.1 s (0%)	477 ms (+15.53% 🔺)	1.6 s
Peer Exchange discovery	52.91 KB (0%)	1.1 s (0%)	508 ms (-13.04% 🔽)	1.6 s
Peer Cache Discovery	46.64 KB (0%)	933 ms (0%)	315 ms (-9.08% 🔽)	1.3 s
Privacy preserving protocols	77.28 KB (0%)	1.6 s (0%)	714 ms (-6.1% 🔽)	2.3 s
Waku Filter	79.72 KB (0%)	1.6 s (0%)	622 ms (-16.1% 🔽)	2.3 s
Waku LightPush	77.99 KB (0%)	1.6 s (0%)	643 ms (-22.44% 🔽)	2.3 s
History retrieval protocols	83.65 KB (0%)	1.7 s (0%)	699 ms (-10.63% 🔽)	2.4 s
Deterministic Message Hashing	28.98 KB (0%)	580 ms (0%)	188 ms (-67.69% 🔽)	767 ms

packages/rln/tsconfig.json

Copilot

Pull Request Overview

This PR migrates the RLN package from ethers.js to viem for Ethereum interactions and introduces automated contract type generation using wagmi CLI. The changes enable type-safe contract interactions by generating TypeScript bindings directly from the smart contract ABIs.

Key changes:

Replaced ethers.js with viem for all blockchain interactions
Automated ABI generation via wagmi CLI from waku-rlnv2-contract repository
Updated all contract interaction code to use viem's type-safe APIs
Added new methods for querying merkle root and merkle proof directly from contracts

Reviewed Changes

Copilot reviewed 21 out of 23 changed files in this pull request and generated 8 comments.

Show a summary per file

File	Description
packages/rln/wagmi.config.ts	Configures wagmi CLI to generate TypeScript bindings from Foundry contracts
packages/rln/src/contract/wagmi/generated.ts	Auto-generated type-safe contract ABIs (977 lines)
packages/rln/src/contract/rln_base_contract.ts	Migrated from ethers Contract to viem getContract with type-safe reads/writes
packages/rln/src/utils/walletClient.ts	New utility to create viem client from window.ethereum
packages/rln/src/types.ts	Updated to use viem WalletClient instead of ethers.Signer
packages/rln/generate_contract_abi.sh	Shell script to clone, build, and generate contract types
packages/rln/package.json	Removed ethers dependency, added viem and wagmi tooling

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packages/rln/src/contract/types.ts

Copilot · 2025-11-12T11:56:12Z

packages/rln/src/contract/rln_base_contract.ts

+    const fromBlock = options.fromBlock
+      ? BigInt(options.fromBlock!)
+      : BigInt(this.deployBlock!);


Redundant non-null assertion after already checking with ternary operator. Line 195 uses options.fromBlock! after already checking options.fromBlock in the ternary condition. The non-null assertion is unnecessary here. Additionally, line 196 uses this.deployBlock! which could be undefined if the create() method hasn't been awaited, leading to a potential runtime error.

Suggested change

const fromBlock = options.fromBlock

? BigInt(options.fromBlock!)

: BigInt(this.deployBlock!);

let fromBlock: bigint;

if (options.fromBlock !== undefined) {

fromBlock = BigInt(options.fromBlock);

} else {

if (this.deployBlock === undefined) {

throw new Error("deployBlock is undefined. Ensure the contract is initialized and create() has been awaited before calling fetchMembers.");

}

fromBlock = BigInt(this.deployBlock);

}

Copilot · 2025-11-12T11:56:13Z

packages/rln/src/contract/rln_base_contract.ts

+    const registeredMemberEvents =
+      await this.contract.getEvents.MembershipRegistered({
+        fromBlock,
+        toBlock: fromBlock + BigInt(options.fetchRange!)


Missing null check for options.fetchRange. Lines 200, 204, and 209 use options.fetchRange! with non-null assertion, but there's no guarantee this value exists. This will cause undefined to be converted to NaN when passed to BigInt(), resulting in a runtime error.

reading it again, we don't actually need these events tracked with the new version of RLN smart contracts

perhaps we will, but I will re-implement when doing #2722

Copilot · 2025-11-12T11:56:13Z

packages/rln/src/contract/rln_base_contract.ts

-      return undefined;
-    }
+  private async getMemberIndex(idCommitmentBigInt: bigint): Promise<number> {
+    return (await this.contract.read.memberships([idCommitmentBigInt]))[5];


Magic number index [5] without explanation. Line 652 accesses array element at index 5 without documentation. According to the ABI at lines 573-584 in generated.ts, index 5 corresponds to the 'index' field of the membership struct. Consider adding a comment or using destructuring with named variables for clarity.

Suggested change

return (await this.contract.read.memberships([idCommitmentBigInt]))[5];

// According to the ABI, index 5 corresponds to the 'index' field of the membership struct

const [, , , , , index] = await this.contract.read.memberships([idCommitmentBigInt]);

return index;

packages/rln/src/contract/rln_base_contract.ts

packages/rln/generate_contract_abi.sh

Copilot · 2025-11-12T11:56:14Z

packages/rln/tsconfig.json

  "include": ["src"],
-  "exclude": ["src/**/*.spec.ts", "src/test_utils"]
-} 
+  "exclude": ["wagmi.config.ts"]


Removed exclusion of test files and test_utils. The original exclusion pattern [\"src/**/*.spec.ts\", \"src/test_utils\"] was removed and replaced with only [\"wagmi.config.ts\"]. This means test files and test utilities will now be included in the build output, which is likely unintended and could increase bundle size.

Suggested change

"exclude": ["wagmi.config.ts"]

"exclude": ["wagmi.config.ts", "src/**/*.spec.ts", "src/test_utils"]

Copilot · 2025-11-12T11:56:14Z

packages/rln/src/contract/rln_base_contract.ts

        return;
      }
-
+      const blockNumber = Number(evt.blockNumber);


Converting blockNumber to Number repeatedly in loop. Line 229 converts evt.blockNumber to Number inside the forEach loop (lines 225-256). If the block number exceeds JavaScript's MAX_SAFE_INTEGER (2^53-1), this conversion will lose precision. Consider keeping as bigint for accuracy or add a check for safe integer range.

current block number on linea sepolia is 20646374 so this shouldn't be an issue

Copilot

Pull Request Overview

Copilot reviewed 21 out of 23 changed files in this pull request and generated 4 comments.

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Copilot · 2025-11-12T21:06:11Z

packages/rln/src/contract/rln_base_contract.ts

+   * Withdraw deposited tokens after membership is erased
+   * @param token - Token address to withdraw
+   * NOTE: Funds are sent to msg.sender (the walletClient's address)


The comment on line 325 mentions that "Funds are sent to msg.sender (the walletClient's address)", but the function signature no longer includes a walletAddress parameter. This is a breaking API change that should be clearly documented. The previous implementation accepted walletAddress as a parameter but now it implicitly uses the wallet client's address. Consider noting this in the PR description or adding a migration guide.

Suggested change

* Withdraw deposited tokens after membership is erased

* @param token - Token address to withdraw

* NOTE: Funds are sent to msg.sender (the walletClient's address)

* Withdraw deposited tokens after membership is erased.

* @param token - Token address to withdraw

* @note Funds are sent to msg.sender (the walletClient's address).

* @breaking The `walletAddress` parameter has been removed. This function now always sends funds to the wallet client's address (`msg.sender`).

Copilot · 2025-11-12T21:06:12Z

packages/rln/README.md

+We use `wagmi` to generate TypeScript bindings for interacting with the RLN smart contracts. When changes are pushed to the `waku-rlnv2-contract` repository, run the following script to fetch and build the latest contracts and generate the TypeScript bindings:
+
+```
+./generate_contract_abi.sh


The script name in package.json is setup:contract-abi but the README refers to ./generate_contract_abi.sh. The npm script should be referenced instead for consistency: npm run setup:contract-abi

Suggested change

./generate_contract_abi.sh

npm run setup:contract-abi

Copilot · 2025-11-12T21:06:12Z

packages/rln/package.json

    "prepublish": "npm run build",
-    "reset-hard": "git clean -dfx -e .idea && git reset --hard && npm i && npm run build"
+    "reset-hard": "git clean -dfx -e .idea && git reset --hard && npm i && npm run build",
+    "setup:contract-abi": "./setup-contract-abi.sh",


The file path in the package.json script is ./setup-contract-abi.sh, but the actual file is named generate_contract_abi.sh. This mismatch will cause the script to fail when executed.

Suggested change

"setup:contract-abi": "./setup-contract-abi.sh",

"setup:contract-abi": "./generate_contract_abi.sh",

thank you robot

packages/rln/src/contract/rln_base_contract.ts

weboko · 2025-11-12T22:37:02Z

packages/rln/src/utils/rpcClient.ts

+    );
+  }
+
+  const [account] = await ethereum.request({ method: "eth_requestAccounts" });


this is not safe if .request doesn't resolve into array

looks like viem has a fully-typed polyfill for window which includes all the rpc requests, replacing with that

what was the fix? I think I still see old code, @adklempner

weboko · 2025-11-12T22:39:26Z

packages/rln/src/contract/constants.ts


 export const RLN_CONTRACT = {
  chainId: 59141,
  address: "0xb9cd878c90e49f797b4431fbf4fb333108cb90e6",


can we get these addresses from some other place similarly to abi?

Unfortunately no; we can move this elsewhere but this is a value that needs to be manually set for now.

weboko · 2025-11-12T22:40:47Z

packages/rln/package.json

-    "reset-hard": "git clean -dfx -e .idea && git reset --hard && npm i && npm run build"
+    "reset-hard": "git clean -dfx -e .idea && git reset --hard && npm i && npm run build",
+    "setup:contract-abi": "./setup-contract-abi.sh",
+    "generate:contract": "npx wagmi generate"


questions:

this command is not needed - if we have previous setup:contract-abi

how is setup:contract-abi supposed to run? before commit / build?

yes we can remove this one

it only needs to be run if the smart contracts are updated and we need to re-generate typings

weboko · 2025-11-12T22:43:33Z

packages/rln/generate_contract_abi.sh

@@ -0,0 +1,42 @@
+#!/bin/bash


this file is not cross platform and will not work on Windows

https://github.com/search?q=org%3Awaku-org+%23%21%2Fbin%2Fbash&type=code

¯_(ツ)_/¯

also, I can't imagine someone trying to make contributions to our repos without WSL, which should enable running bash...

¯_(ツ)_/¯

there is no js-waku related script that are needed for contribution

I can't imagine someone trying to make contributions to our repos without WSL

and what exactly requiring WSL?

weboko

good first iteration

left comments in addition to Copilot's

and make sure you properly integrate it with release CI

Copilot

Pull Request Overview

Copilot reviewed 21 out of 23 changed files in this pull request and generated 5 comments.

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packages/rln/generate_contract_abi.sh

packages/rln/src/contract/rln_base_contract.ts

Copilot

Pull Request Overview

Copilot reviewed 21 out of 23 changed files in this pull request and generated 7 comments.

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Copilot · 2025-11-20T12:54:27Z

packages/rln/src/contract/rln_base_contract.ts

-    instance.maxRateLimit = ethers.BigNumber.from(max).toNumber();
+
+    instance.minRateLimit = min;
+    instance.maxRateLimit = max;


The type assertion address! as \0x${string}`` uses the non-null assertion operator which could throw at runtime if address is undefined. Consider adding a runtime check instead:

if (!address) { throw new Error("Contract address is required"); }

Copilot · 2025-11-20T12:54:28Z

packages/rln/src/contract/rln_base_contract.ts

+        }
+      );
+    } catch (err) {
+      throw new Error("Failed to simulate register membership: " + err);


Another error message formatting issue. Consider using proper error formatting:

throw new Error(`Failed to simulate register membership: ${err instanceof Error ? err.message : String(err)}`);

Suggested change

throw new Error("Failed to simulate register membership: " + err);

throw new Error(

`Failed to simulate register membership: ${err instanceof Error ? err.message : String(err)}`

);

Copilot · 2025-11-20T12:54:28Z

packages/rln/src/contract/rln_base_contract.ts

+   * and will only send tokens to that address.
+   * @param token - Token address to withdraw
+   */
+  public async withdraw(token: string): Promise<Hash> {


The withdraw method signature has changed - it no longer requires walletAddress parameter. This is a breaking change. The documentation comment explains this is intentional (the smart contract validates the sender), but consider whether the removal of this parameter might confuse users who were previously required to provide it. The comment at line 323 correctly documents the new behavior.

Copilot · 2025-11-20T12:54:28Z

packages/rln/src/contract/types.ts


 export interface MembershipInfo {
-  index: ethers.BigNumber;
+  index: number;


The index type has changed from ethers.BigNumber to number. This is a breaking change that could cause issues if index values exceed JavaScript's MAX_SAFE_INTEGER (2^53 - 1). Consider whether membership indices could realistically exceed this limit, and if so, keep using bigint instead.

Suggested change

index: number;

index: bigint;

Copilot · 2025-11-20T12:54:29Z

packages/rln/src/contract/rln_base_contract.ts

      }

      return {
        index,


The index field is assigned directly from the contract without type conversion, but the MembershipInfo type expects index: number. Since the contract returns uint32, this should be safe, but for consistency with other conversions in this function, consider explicitly converting:

index: Number(index),

Suggested change

index,

index: Number(index),

Copilot · 2025-11-20T12:54:29Z

packages/rln/src/contract/rln_base_contract.ts

+        }
+      );
+    } catch (err) {
+      throw new Error("Error simulating eraseMemberships: " + err);


Similar error message formatting issue. Consider using proper error formatting:

throw new Error(`Error simulating eraseMemberships: ${err instanceof Error ? err.message : String(err)}`);

Suggested change

throw new Error("Error simulating eraseMemberships: " + err);

throw new Error(`Error simulating eraseMemberships: ${err instanceof Error ? err.message : String(err)}`);

Copilot · 2025-11-20T12:54:29Z

packages/rln/src/contract/rln_base_contract.ts

+        account: this.rpcClient.account.address
+      });
+    } catch (err) {
+      throw new Error("Error simulating withdraw: " + err);


Another error message formatting issue. Consider using proper error formatting:

throw new Error(`Error simulating withdraw: ${err instanceof Error ? err.message : String(err)}`);

Suggested change

throw new Error("Error simulating withdraw: " + err);

throw new Error(`Error simulating withdraw: ${err instanceof Error ? err.message : String(err)}`);

weboko · 2025-11-20T14:06:15Z

from previous review one point is not addressed

and make sure you properly integrate it with release CI

I think we should:

re-generate contract primitive before release
try to build waku/rln and if fails - fail further release of this package
update release TODO list in Notion to make sure we don't forget to keep an eye on it

weboko

lgtm

please, address other comments before merge

adklempner force-pushed the feat/rln-contract-gen-types branch from 1fcf108 to a88dd8c Compare October 24, 2025 22:43

adklempner force-pushed the feat/rln-contract-gen-types branch from 264f2c0 to 5ea574e Compare October 27, 2025 20:48

This was referenced Oct 28, 2025

feat: use viem instead of ethers waku-org/rln.waku.org#20

Open

feat(rln): proof generation and verification #2716

Draft

adklempner force-pushed the feat/rln-contract-gen-types branch 3 times, most recently from 70922e5 to 7e5680f Compare November 11, 2025 21:42

adklempner marked this pull request as ready for review November 12, 2025 03:58

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adklempner force-pushed the feat/rln-contract-gen-types branch from 93c152a to e0c6a09 Compare November 13, 2025 01:37

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feat: use wagmi to generate contract types

904d648

adklempner added 10 commits November 17, 2025 18:38

feat: migrate rln from ethers to viem

89defd3

fix: remove .gitmodules

aa1e197

fix: update readme

64aef7b

fix: refactor to use a single viem client object

ad24c6c

fix: update comments, tsconfig

4672f83

feat: remove membership event tracking

2cda197

fix: script name in package.json and readme

31b8d32

fix: only allow linea sepolia

a8f1bfa

fix: consolidate viem types, typed window

f07f3cf

fix: use viem to infer type of decoded event

8221064

adklempner force-pushed the feat/rln-contract-gen-types branch from 44ad556 to 8221064 Compare November 18, 2025 02:38

weboko requested a review from Copilot November 20, 2025 12:50

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weboko approved these changes Nov 20, 2025

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adklempner added 2 commits November 20, 2025 15:10

fix: use js for generate abi script

25dce8c

feat: generate abi and build rln package as release condition

0b90116

-    const fromBlock = options.fromBlock
-      ? BigInt(options.fromBlock!)
-      : BigInt(this.deployBlock!);
+    let fromBlock: bigint;
+    if (options.fromBlock !== undefined) {
+      fromBlock = BigInt(options.fromBlock);
+    } else {
+      if (this.deployBlock === undefined) {
+        throw new Error("deployBlock is undefined. Ensure the contract is initialized and create() has been awaited before calling fetchMembers.");
+      }
+      fromBlock = BigInt(this.deployBlock);
+    }

-    return (await this.contract.read.memberships([idCommitmentBigInt]))[5];
+    // According to the ABI, index 5 corresponds to the 'index' field of the membership struct
+    const [, , , , , index] = await this.contract.read.memberships([idCommitmentBigInt]);
+    return index;

	"exclude": ["wagmi.config.ts"]
	"exclude": ["wagmi.config.ts", "src/*/.spec.ts", "src/test_utils"]

	"setup:contract-abi": "./setup-contract-abi.sh",
	"setup:contract-abi": "./generate_contract_abi.sh",

	throw new Error("Error simulating eraseMemberships: " + err);
	throw new Error(`Error simulating eraseMemberships: ${err instanceof Error ? err.message : String(err)}`);

	throw new Error("Error simulating withdraw: " + err);
	throw new Error(`Error simulating withdraw: ${err instanceof Error ? err.message : String(err)}`);

feat(rln)!: generate contract types, migrate from ethers to viem #2705

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feat(rln)!: generate contract types, migrate from ethers to viem #2705

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size-limit report 📦

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