`dataSuffix` passed to `createConfig` is not applied to transactions sent through the connector client

[t0rbik]

Check existing issues

• I checked there isn't already an issue for the bug I encountered.

Describe the bug

I am passing dataSuffix to createConfig as the Base Builder Codes docs suggest (https://docs.base.org/base-chain/builder-codes/app-developers, "Quick Setup with Wagmi"):

const config = createConfig({
  chains: [base],
  transports: { [base.id]: http() },
  dataSuffix: DATA_SUFFIX,
});

It type-checks, but transactions sent with useWalletClient().data.sendTransaction, useWriteContract or useSendCalls do not include the suffix in their calldata.

createConfig forwards the extra client properties only into the public client in getClient. The connector client in getConnectorClient is built with account, chain, name and transport only, so client.dataSuffix is never set on it and viem's wallet actions have nothing to read:

https://github.com/wevm/wagmi/blob/main/packages/core/src/actions/getConnectorClient.ts

With the client() form of createConfig the option cannot be passed at all, OneOf types it as undefined.

I would expect dataSuffix on the config to reach the connector client, since viem's sendTransaction, writeContract and sendCalls already read client.dataSuffix.

Link to Minimal Reproducible Example

No response

Steps To Reproduce

1. anvil --fork-url https://mainnet.base.org --port 8545
2. Run the script below with @wagmi/core 3.6.5 (mock connector, transports form config with dataSuffix)
3. Every transaction sent through wagmi's write actions or the connector client has no suffix in input; the rebuilt client in the same run does

import { createConfig, http, connect, sendTransaction, getWalletClient, getClient, mock } from "@wagmi/core";
import { base } from "viem/chains";
import { createWalletClient, custom } from "viem";
import { Attribution } from "ox/erc8021";

const RPC = "http://127.0.0.1:8545";
const chain = { ...base, rpcUrls: { default: { http: [RPC] } } };
const ACCOUNT = "0xf39Fd6e51aad88F6F4ce6aB8827279cffFb92266"; // anvil #0
const DATA_SUFFIX = Attribution.toDataSuffix({ codes: ["bc_959ju7ya"] });

const config = createConfig({
  chains: [chain],
  connectors: [mock({ accounts: [ACCOUNT] })],
  transports: { [chain.id]: http(RPC) },
  dataSuffix: DATA_SUFFIX,
});
await connect(config, { connector: config.connectors[0] });

const publicClient = getClient(config);
const walletClient = await getWalletClient(config);
console.log(publicClient.dataSuffix); // 0x62635f...8021
console.log(walletClient.dataSuffix); // undefined

const check = async (label, hash) => {
  const tx = await publicClient.request({ method: "eth_getTransactionByHash", params: [hash] });
  console.log(label, tx.input.endsWith(DATA_SUFFIX.slice(2)), tx.input);
};

await check("sendTransaction(config)", await sendTransaction(config, { to: ACCOUNT, value: 0n }));
await check("getWalletClient().sendTransaction", await walletClient.sendTransaction({ to: ACCOUNT, value: 0n }));

const rebuilt = createWalletClient({
  account: walletClient.account,
  chain: walletClient.chain,
  transport: custom({ request: walletClient.request }, { retryCount: 0 }),
  dataSuffix: DATA_SUFFIX,
});
await check("rebuilt.sendTransaction", await rebuilt.sendTransaction({ to: ACCOUNT, value: 0n }));

Output:

0x62635f3935396a753779610b0080218021802180218021802180218021
undefined
sendTransaction(config) false 0x
getWalletClient().sendTransaction false 0x
rebuilt.sendTransaction true 0x62635f3935396a753779610b0080218021802180218021802180218021

writeContract(config) and sendCalls(config) behave the same way.

In the app I use the same rebuild inside useWalletClient's query.select; with it the suffix lands on chain.

What Wagmi package(s) are you using?

wagmi, @wagmi/core

Wagmi Package(s) Version(s)

wagmi 3.7.7, @wagmi/core 3.6.5

Viem Version

2.56.3

TypeScript Version

7.0.2

Anything else?

Happy to open a PR forwarding dataSuffix into getConnectorClient if that direction works for you.

[Tiancheng-Xu]

I’d like to work on this. I’ll add regression coverage showing that config-level dataSuffix reaches the connector client, then make the smallest forwarding change needed for the existing wallet actions.