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The to header is normally optional when creating a smart contract… But though reading JSON-RPC documentation, I saw it was possible to set the To field of a transaction creating a smart contract ?
Does the field is ignored in the case of contract creation ? If yes, please quote the source code lines where the recipient is ignored (as an example in a widely used implementation) ? If not what it does since it doesn’t sets contract address ?
The actual behavior is described in the Yellow Paper section 4.2. The Transaction:
to: The 160-bit address of the message call’s recipient or, for a contract creation transaction, ∅, used here to denote the only member of B0; formally Tt.
The only possible values for to are:
to will contain the 0 address as null is not a recognized state. The 0 address links to an external account (which we all know contains a trove of ether and tokens). So, how does ethereum distinguish a contract creation request from a value transfer request originating from sender to address 0x0?
Jun 14, 2018 at 2:33
data property then determine whether this is a contract creation request, e.g., parser sees to == 0x0 && data == 0x0 and results in value transfer to 0x0.
Jun 14, 2018 at 2:43
undefined to represent contract creation (it is unfortunate feature of the language that 0 can be used instead of undefined).
The way you indicate that a transaction is creating a contract is to use an empty to address. This is equivalent to leaving it out in the JSON-RPC interface.
If you set it to something non-empty, the transaction will not create a contract.
This is only relative to the ᴊꜱᴏɴ-ʀᴘᴄ protocol : In order to get a transaction treated as contract creation, to must be unset as shown by go-ethereum :
func (st *StateTransition) TransitionDb() (ret []byte, usedGas uint64, failed bool, err error) {
if err = st.preCheck(); err != nil {
return
}
msg := st.msg
sender := vm.AccountRef(msg.From())
homestead := st.evm.ChainConfig().IsHomestead(st.evm.BlockNumber)
contractCreation := msg.To() == nil
