method for calling to entry point of contract instance (?) created by contract.create

Question

Contract A is not able to find the address of the contract created by contract.create. Tried adding the signature of B as well as it's complete definition in contract A but still, it doesn't solve the issue.

Contract A is as described below:

[%%version 0.9]

(* Contract A *)

(*Signature of contract B*)
  (*
    contract ContractB = struct
      type storage = nat 
      let%init storage (param : nat) = (param) 
      let%entry update_param
          (param : nat) (storage: storage) = [], storage 
    end*)

contract ContractB = struct 
  type storage = nat 
  let%init storage (param: nat) = (param) 
  let%entry update_param
      (param : nat) (storage: storage) = 
    let storage = param in 
    [], storage
end

(*Signature of contract A*)
contract ContractA = struct
  type storage = address 
  let%init storage (param : address) = (param) 
  let%entry create_InstanceB (param : nat) (storage: storage) = [], storage
  let%entry call_InstanceB (param : nat) (storage: storage) = [], storage 
end

type storage = address

let%init storage (param : address) = (param)

let%entry create_InstanceB (param : nat) (storage: storage) = 

  let mgr = tz1RYq8wjcCbRZykY7XH15WPkzK7TWwPvJJt in 
  (* Creating the instance of B *)
  let (op, b_addr) = 
    Contract.create 
      ~manager:mgr 
      ~delegate:None
      ~spendable:true 
      ~delegatable:true 
      ~amount:100tz
      (param) 
      (contract ContractB) 
  in
  let storage = b_addr in
  [], storage


let%entry call_InstanceB (param : nat) (storage: storage) = 
  let addr1 =  storage in
  let _contract = (Contract.at addr1 : ContractB.instance option)  in
  match _contract with 
  |None -> Current.failwith ("Not able to find contract B's instance.");
  |Some contract_ -> (*Current.failwith ("Found some contract's instance.");*)
      let op = Contract.call ~dest:contract_ ~amount:0tz ~entry:update_param ~parameter:(param) in
      [op], storage

Contract B is as below:

[%%version 0.9]

(* Contract B *)

(*Signature of contract B*)
contract ContractB = struct
  type storage = nat 
  let%init storage (param : nat) = (param) 
  let%entry update_param
      (param : nat) (storage: storage) = [], storage 
end

type storage = nat

let%init storage (param: nat) = (param)

let%entry update_param
    (param : nat) (storage: storage) = 
  let storage = param in 
  [], storage

First I have deployed the contract B and then A and then performed a call to entry point "create_and_call_InstanceB" of A but got the following Error:

Error
liquidity_buffer:58.11-58.72: Failed at runtime: in failed
Failed with "Not able to find contract B's instance."
Call to contract failed

If I don't perform the contract call and try getting the address of created contract and try performing call to one of it's entry points, I get the following error:

Error
Response error: in failed
- temporary: proto.003-PsddFKi3.contract.non_existing_contract
Call to contract failed

Seems like something very basic is missing here from conceptual point of view. Please explain the following:

a) Is it needed that contract B should be deployed first and then it's instance can be created by contract.create? If so, which prototype of contract B will be taken at the time of instantiation of contract B from contract.create?

b) If above is not the right way then how to create and deploy a contract from another contract and then perform a call to an entry point of a newly created contract?

c) How to create an instance of already deployed contract and perform a call to an entry point of that instance?

Answer 1

You cannot create a contract and call it immediately.

It goes like this, chronologically:

• Your script is running. You invoke CREATE_CONTRACT or CREATE_ACCOUNT. An operation and address are returned and your script continues on. The operation will create the account after your script returns it. Right now, the account does not exist.
• You now immediately try to CONTRACT p on the address, to get a contract p so that you can call TRANSFER_TOKENS. This fails, because the contract doesn't exist.

To work around this, you could either break the functionality into two top-level operations, or have the script transfer to itself (returning the create account operation, and then the transfer) in order to run more code after the account is created.