[Bug] TxEnvelop json decoding fails with confusing error message

[ufoscout]

Component

serde

What version of Alloy are you on?

alloy v0.6.4

Operating System

Linux

Describe the bug

Deserializing a TxEnvelop produces a confusing error message: Error("data did not match any variant of untagged enum MaybeTaggedTxEnvelope", line: 0, column: 0) independently of the real error.

For example, this fails and there's no way to know why:

#[test]
fn test_serde_tx_envelop() {
    let data = r#"
    {
        "hash":"0x0000000000000000000000000000000000000000000000000000000000000000",
        "input":"0x",
        "r": "0x1",
        "s": "0x0",
        "v": "0x1",
        "gas":"0x2710",
        "from":"0x0202020202020202020202020202020202020202",
        "to":null,
        "value":"0x0",
        "nonce":"0x0",
        "gasPrice":"0x4e20",
        "type":"0x0"
    }
    "#;
    let _tx: TxEnvelope = serde_json::from_str(data).unwrap();
}

I am not sure why, but the error disappears if you change from "v": "0x1" to "v": "0x1c".

This test also fails because the hash length is 63 instead of 64, but the error reported makes it impossible to find it:

#[test]
fn test_serde_tx_envelop() {
    let data = r#"
    {
        "hash":"0x00000000000000000000000000000000000000000000000000000000000000",
        "input":"0x",
        "r": "0x1",
        "s": "0x0",
        "v": "0x1c",
        "gas":"0x2710",
        "from":"0x0202020202020202020202020202020202020202",
        "to":null,
        "value":"0x0",
        "nonce":"0x0",
        "gasPrice":"0x4e20"
    }
    "#;
    let _tx: TxEnvelope = serde_json::from_str(data).unwrap();
}

[klkvr]

Did you get this JSON payload from a real RPC response? This transaction matches legacy transaction and for them we are expecting v as 27/28. If it's not the case for some endpoint, we can look into adapting this

[mattsse]

we can def improve the error message by handrolling the deserde impl which would have the benefit of making this a lot more efficient, but would be a bit messy

[Toeplitz]

I'm getting the same error on my base network provider with this code:

    let block = provider.get_block_by_number(block_num, BlockTransactionsKind::Hashes).await?;

    if let Some(block) = block {
        let txs = block.transactions.as_hashes().unwrap();

        for hash in txs {
            let tx = provider.get_transaction_by_hash(*hash).await?;
            println!("tx = {:#?}", tx)
        }

Gives error:

Error: deserialization error: data did not match any variant of untagged enum MaybeTaggedTxEnvelope at line 1 column 888

Caused by:
data did not match any variant of untagged enum MaybeTaggedTxEnvelope at line 1 column 888

Related to the bug I reported here: #1716

The code works fine on the ethereum network.