impersonated accounts do not get returned by eth_accounts

[MartinquaXD]

Component

Anvil

Have you ensured that all of these are up to date?

• Foundry
• Foundryup

What version of Foundry are you on?

forge 0.2.0 (ae3ec74 2023-08-26T00:18:16.173100000Z)

What command(s) is the bug in?

No response

Operating System

macOS (Apple Silicon)

Describe the bug

I'm trying to use an impersonated account via ethers.js with this function:

export const impersonate = async (address: string, provider: ethers.JsonRpcProvider) => {
  // Impersonate the account
  await provider.send("anvil_impersonateAccount", [address]);

  // Create a signer for the impersonated account
  return await provider.getSigner(address);
}

Which fails with following error (anvil output included as it gives a bit more context):

Listening on 127.0.0.1:8545
eth_chainId
anvil_impersonateAccount
eth_accounts
eth_chainId
error: Uncaught (in promise) Error: invalid account
    at JsonRpcProvider.getSigner (file:///Users/martin/work/ethers/node_modules/.deno/ethers@6.7.1/node_modules/ethers/lib.esm/providers/provider-jsonrpc.js:717:15)
    at Object.runMicrotasks (ext:core/01_core.js:838:30)
    at processTicksAndRejections (ext:deno_node/_next_tick.ts:53:14)
    at runNextTicks (ext:deno_node/_next_tick.ts:71:5)
    at eventLoopTick (ext:core/01_core.js:189:21)
    at async impersonate (file:///Users/martin/work/ethers/src/utils.ts:61:10)
    at async file:///Users/martin/work/ethers/src/test.ts:10:16

After digging a bit I think ethers.js expects all accounts the node can sign transactions as to be returned by eth_accounts which conforms with the spec. However, when using anvil_impersonateAccount the list of addresses returned by eth_account does not change which leads to this incompatibility with ethers.js. Although this seems to work when using anvil from rust as it's shown in the can_impersonate_account test.

I adjusted the test with the provided diff to show that anvil_impersonateAccount indeed does not change the list reported by eth_account. It looks in the code that impersonated accounts and the accounts managed by the node from the beginning are stored in 2 places (CheatsState::impersonated_accounts vs. EthApi::signers) which would both have to be queried for a fix.

test setup

Run test with: cargo test -- can_impersonate_account --nocapture

Diff:

diff --git a/crates/anvil/tests/it/anvil_api.rs b/crates/anvil/tests/it/anvil_api.rs
index a4213dc4..b4b1a93f 100644
--- a/crates/anvil/tests/it/anvil_api.rs
+++ b/crates/anvil/tests/it/anvil_api.rs
@@ -81,7 +81,10 @@ async fn can_impersonate_account() {
     let res = provider.send_transaction(tx.clone(), None).await;
     res.unwrap_err();
 
+    let before_impersonation = api.accounts().unwrap();
     api.anvil_impersonate_account(impersonate).await.unwrap();
+    let after_impersonation = api.accounts().unwrap();
+    assert_ne!(before_impersonation, after_impersonation);
 
     let res = provider.send_transaction(tx.clone(), None).await.unwrap().await.unwrap().unwrap();
     assert_eq!(res.from, impersonate);