`bundlerClient.sendUserOperation` pays way too much for gas

[johanneskares]

Check existing issues

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

Viem Version

2.23.6

Current Behavior

When sending a transaction using bundlerClient.sendUserOperation the gas price is way to high.

Here's a AA transaction, that was created using sendUserOperation on Base. Gas Price was over 1 Gwei.
https://basescan.org/tx/0xe1c9399343ea62ebf247492d6c8efc1c3e16ac38118b78cdeda1887333d8cc3b

The corresponding Bundler TX has only a gas price of 0.003 Gwei, so a 300x difference, so I massively overpaid the bundler.
https://basescan.org/tx/0x607f66017375f1eb655f931fdffb39e9ab6d349a9c60a1544d1869c979e9f01d

I tried it with both Pimlico Bundler and Coinbase Bundler, same result.

My quick fix was to do this

const userOpHash = await bundlerClient.sendUserOperation({
    calls: [...],
    maxFeePerGas: 2n * (await bundlerClient.client.getGasPrice()),
});

Is it possible that this should be Math.min? :

viem/src/account-abstraction/actions/bundler/prepareUserOperation.ts

Line 442 in c52c8ed

Math.max(

Currently, prepareUserOperation returns at least 3 Gwei for maxFeePerGas, doesn't really make sense.

Expected Behavior

Gas Price for sendUserOperation should be close to current gas price.

Steps To Reproduce

Use bundlerClient.sendUserOperation and send a transaction.

Link to Minimal Reproducible Example

No response

Anything else?

No response

[jxom]

This is because 4337 bundlers are unfortunately very brittle and some break when a fee is set below a price of 3 gwei 😅