zero-length unformatted data fields should return 0x, not 0x0

[aakilfernandes]

Not sure if this is an issue or not, but eth_getCode returns 0x0 for non-contract accounts. My assumption is that it should return 0x.

[benjamincburns]

Hi @aakilfernandes! Funny story. I just started writing up a nice polite response telling you how wrong your assumption is, and then I went to grab a reference link from the Ethereum RPC wiki and discovered what an incorrect, smug jerk I am! 😂

You're absolutely correct - unformatted data values which are zero length should be returned as 0x.

Does this break anything for you?

[benjamincburns]

Was hoping to knock this out quickly, but I hit some snags. Will need to come back to it later. PRs welcome.

[jordanschalm]

A possible side-effect of this issue is sometimes non-zero fields are prefixed with a zero, which Geth no longer accepts as valid. For example 0x1234 would be returned by Ganache as 0x01234.

I have seen this occurring with eth_getBlockByNumber. Ganache returns the following transaction within the JSON response:

{  
    "hash":"0x3f8d3b83b6b14a020d8bb0a088027fc0ae5004feeb063e11841103ce6a331153",
    "nonce":"0x0",
    "blockHash":"0xcf57c1d749ce9c28cb6424c99e50f67641ebe78cc27f43a9751de64344f66df8",
    "blockNumber":"0x01",
    "transactionIndex":"0x00",
    "from":"0x627306090abab3a6e1400e9345bc60c78a8bef57",
    "to":"0xf17f52151ebef6c7334fad080c5704d77216b732",
    "value":"0x5af3107a4000",
    "gas":"0x5208",
    "gasPrice":"0x04a817c800",
    "input":"0x0"
}

gasPrice (non-zero) and nonce/input (zero) are both prefixed by a zero. This causes Geth's standard ethclient to fail while unmarshalling the response with the following error:

json: cannot unmarshal hex number with leading zero digits into Go struct field rpcBlock.transactions of type *hexutil.Big

[crzndx]

i also realized, that empty arrays return inconsistent results if empty, e.g. [0x0, 0x, 0x, ...]

[benjamincburns]

This should be fixed in develop by #92. Thanks for the contribution @AusIV!

[HowardBraham]

I don't think this issue was completely fixed before. I have submitted #171 to try to resolve it.