Add all signers to the Transaction when serializing with ToStackItem

[shargon]

Close #2460

[cloud8little]

Testing

[cloud8little]

Since the Signers is converted to ByteString, how can it be converted back to Signer type in the contract? The fourth result of Array type is the returned Signers. As @csmuller mentioned, I think the scripthash of the signers accounts is enough. Besides, I prefer to reserve the original Sender field, which can save a lot of time to make existing contract compatible when they use tx.Sender a lot.

{
  "jsonrpc": "2.0",
  "id": 1,
  "result": {
    "script": "wh8MC2NoZWNrU2lnbmVyDBRTmj3IXRZ1Tf+gBpCEMh4YG3SmkEFifVtS",
    "state": "HALT",
    "gasconsumed": "1050210",
    "exception": null,
    "stack": [
      {
        "type": "Array",
        "value": [
          {
            "type": "ByteString",
            "value": "qO1jTXO3f137AmS91H3MSookn8NFTdPtqgaURWsdf68="
          },
          {
            "type": "Integer",
            "value": "0"
          },
          {
            "type": "Integer",
            "value": "0"
          },
          {
            "type": "Array",
            "value": [
              {
                "type": "ByteString",
                "value": "fu4aq+tn7R15HUTk9fzzrpFxqHEQBPlbZ8nQL4JCkov3isQhmpO9EP21fj0kMR6lYXRJjn3DJQem7XroYNUBXdiaWwTnWPtnw6I+BU6v20QSknqeDm1/DzmQMR8r4GiZ90DEZznR"
              },
              {
                "type": "ByteString",
                "value": "Edm1mjSxnQkQ+yCRGOv8WYg6rvwQBPlbZ8nQL4JCkov3isQhmpO9EP21fj0kMR6lYXRJjn3DJQem7XroYNUBXdiaWwTnWPtnw6I+BU6v20QSknqeDm1/DzmQMR8r4GiZ90DEZznR"
              }
            ]
          },
          {
            "type": "Integer",
            "value": "0"
          },
          {
            "type": "Integer",
            "value": "0"
          },
          {
            "type": "Integer",
            "value": "0"
          },
          {
            "type": "ByteString",
            "value": ""
          }
        ]
      }
    ]
  }
}

[superboyiii]

We should avoid any incompatible changes on RC3 only if it's very critical.

[shargon]

The option B it's serialize Signers at the end, I think that this option it's most optimal, what do you prefer @erikzhang ?

[erikzhang]

The option B it's serialize Signers at the end

I think it's okay. But why do we need this?

[shargon]

I think it's okay. But why do we need this?

SC maybe will need to know all the signers

[erikzhang]

How to deserialize it in a contract?

[shargon]

Only the address better?

[erikzhang]

@csmuller Does it work for you?

[roman-khimov]

Think of contract-sponsored transactions that rely on contract's verify method. I want to see signers there, but I'd also like to see their witness scopes so that I could check them. Otherwise user can send {{0xCONTRACT, Global}, {0xUSER, Whatever}} transaction and if contract approves it then transaction could steal some assets from it.

Or maybe it can be generalized, even if contract is not a sender it still should be worried about its witness scope.

[erikzhang]

I think we should answer the question first: why do we need to read the signers in a contract?

[roman-khimov]

To implement some checks in verify?

[erikzhang]

Maybe we can create some syscalls to handle it? Just like CheckWitness?