debug_traceCall

Overview

debug_traceCall is an Ethereum RPC method that allows you to execute a given call (message), tracing the steps of its execution. This can be helpful for developers and auditors who want to inspect and analyze the internal operations and state changes of a contract call without modifying the blockchain state. This method can assist in debugging and identifying potential issues with contract execution, as well as understanding how gas is consumed during the execution of a call.

Parameters

1. Transaction call object (required)

object - The eth_call data

2. Block parameter (required)

• hexadecimal block number
• block hash
• The Tag "latest", "earliest", "pending", "safe" or "finalized" "Safe" and "finalized" are only available on Ethereum and Arbitrum One chain. Ethereum documentation.

3. Trace type (optional)

• The type of tracer - String - It might be callTracer or prestateTracer
  • callTracer - The calltracer keeps track of all call frames, including depth 0 calls, that are made during a transaction.
  • prestateTracer - The prestateTracer replays the transaction and tracks every part of state that occured during the transaction.
• tracerConfig - The object to specify the configurations of the tracer
  • onlyTopCall - When set to true, this will only trace the primary (top-level) call and not any sub-calls. It eliminates the additional processing for each call frame.

Additional configuration parameters

• disableStorage — when enabled, it prevents tracing of storage changes made by the transaction being analyzed, which can reduce the resource requirements of the analysis. By default, debug_traceTransaction traces both memory and storage changes, but storage tracing can be particularly resource-intensive, especially for large transactions.
• disableStack — when enabled, it skips tracing of stack changes made by the transaction being analyzed.
• disableMemory — when true, it stops tracing of memory changes made by the transaction being analyzed, reducing resource requirements.
• disableReturnData — when true, it prevents the method from tracing the return data of a transaction. This return data tracing can be very demanding on resources, as it requires a lot of time and processing power.
• timeout (default: 5s) — allows to customize the method's timeout period for JavaScript-based tracing calls.

🚧

When using a tracer type , disableMemory, disableStorage, disableStack, or disableReturnData will not have any effect. When no tracer is selected, the response defaults to Struct/opcode logger.

Returns

callTracer response:

prestateTracer response

• smart contract address — The address of the smart contract associated with the result.
  • balance — The balance of the contract, expressed in wei and encoded as a hexadecimal string.
  • code — The bytecode of the contract, encoded as a hexadecimal string.
  • nonce — The nonce of the account associated with the contract, represented as an unsigned integer.
  • storage — A map of key-value pairs representing the storage slots of the contract. The keys and values are both encoded as hexadecimal strings.

Struct/opcode response

• The transaction trace object:
• failed - Successful or failed
• gas - The total consumed gas in the transaction
• returnValue - The return value of the executed contract call
• structLogs - The trace result of each step:
  • pc - The current index in bytecode.
  • op - The name of current executing operation.
  • gas - The available gas in the execution.
  • gasCost - The gas cost of the operation.
  • depth - The number of levels of calling functions.
  • stack - An array of values in the current stack.
  • storage - The mapping of the current storage.
  • refund - The total of current refund value.
  • error - The error of the execution.
  • memory - An array of values in the current memory.

Request Example

curl --location 'https://api.tatum.io/v3/blockchain/node/ethereum-mainnet/' \
--header 'Content-Type: application/json' \
--header 'x-api-key: {API_KEY}' \
--data '{
    "method":"debug_traceCall",
    "params":[{
        "to":"0x742d35Cc6634C0532925a3b844Bc454e4438f44e"
        },
        "latest"
    ],
    "id":1,
    "jsonrpc":"2.0"
}'

// yarn add @tatumio/tatum

import { TatumSDK, Ethereum, Network } from '@tatumio/tatum'

const tatum = await TatumSDK.init<Ethereum>({network: Network.ETHEREUM})

const result = await tatum.rpc.debugTraceCall({
      "from": "0xa7d9ddbe1f17865597fbd27ec712455208b6b76d",
      "to": "0x742d35Cc6634C0532925a3b844Bc454e4438f44e",
      "gas": "0x76c0",
      "gasPrice": "0x9184e72a000",
      "value": "0x9184e72a",
      "data": "0x606060..."
    },
    "0x1b4",
    {
  tracer: 'callTracer',
  tracerConfig: {
      onlyTopCall: true,
      timeout: '5s',
  }
}
)

await tatum.destroy() // Destroy Tatum SDK - needed for stopping background jobs