feat(cheatcodes): add way to access the broadcasted transactions hashes inside of the current forge script run

[CodeSandwich]

Component

Forge

Describe the feature you would like

Currently transactions made with vm.broadcast are built, signed and stored in the JSON report by forge script, but they can't be accessed from the inside of the script itself. It would be great if the list of the hashes of the broadcasted transactions could be somehow obtained.

Additional context

Personally I would use it to document the operations made by the script. The current behavior of printing to STDOUT a message including the path to the transactions JSON makes automation rather difficult as it requires parsing the output and running custom tools after the script finishes.

[zerosnacks]

Hi @CodeSandwich thanks for your suggestion

I think this can be resolved by implementing the cheatcodes outlined in #4732

Marking in favor of that ticket, let me know if this is not accurate

[CodeSandwich]

Hi @zerosnacks,
Thank you for the insight, but I disagree with your assessment. #4732 is about addresses of deployed contracts, and this issue is about the transactions that are being made. These are 2 very different functionalities, and getting deployed contract addresses does NOT enable access to transaction hashes.

[zerosnacks]

I see, would it be solved if there was a cheatcode that would return additional information (struct Broadcast {...}, like a getBroadcast(string calldata artifactPath) returns (Broadcast broadcast) which includes both transactions and receipts?

A broadcast log looks like:

{
  "transactions": [
    {
      "hash": "0x26b118bd763de327628f1bf80044f6f9fe3d4156fdd398e642eb5d3f598f1903",
      "transactionType": "CREATE",
      "contractName": "Counter",
      "contractAddress": "0x5FbDB2315678afecb367f032d93F642f64180aa3",
      "function": null,
      "arguments": null,
      "transaction": {
        "from": "0xf39Fd6e51aad88F6F4ce6aB8827279cffFb92266",
        "gas": "0x21de9",
        "value": "0x0",
        "input": "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",
        "nonce": "0x0",
        "chainId": "0x7a69"
      },
      "additionalContracts": [],
      "isFixedGasLimit": false
    }
  ],
  "receipts": [
    {
      "status": "0x1",
      "cumulativeGasUsed": "0x1a0ed",
      "logs": [],
      "logsBloom": "0x00000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000",
      "type": "0x2",
      "transactionHash": "0x26b118bd763de327628f1bf80044f6f9fe3d4156fdd398e642eb5d3f598f1903",
      "transactionIndex": "0x0",
      "blockHash": "0x1bc0d6b4ed134a975e24c3d7ef64be4955aedd3dd728c01a956bc9c25c3d8ce0",
      "blockNumber": "0x1",
      "gasUsed": "0x1a0ed",
      "effectiveGasPrice": "0x3b9aca01",
      "blobGasPrice": "0x1",
      "from": "0xf39Fd6e51aad88F6F4ce6aB8827279cffFb92266",
      "to": null,
      "contractAddress": "0x5FbDB2315678afecb367f032d93F642f64180aa3",
      "root": "0x77a991671f45707778fafeb999ad80ec0c801d2cfb1b5683aa34a7ba0a39ba9b"
    }
  ],
  "libraries": [],
  "pending": [],
  "returns": {},
  "timestamp": 1728567099,
  "chain": 31337,
  "commit": "faef157"
}

From which we could extract the transaction hashes, etc..

If so, I still think we can expand the scope of #4732 to include this request

[CodeSandwich]

Yes, getBroadcast effectively returning the content of the broadcast summary JSON would be a great solution, it would cover the need for transaction hashes.

Is there a need for the artifactPath parameter? Scripts can't discover the previous runs, so it would require somebody to manually find the right broadcast/<SCRIPT>/<CHAIN-ID>/run-<ID>.json path and somehow passed it into the script. How would it be useful anyway? IMO artifactPath could be dropped and getBroadcast() could always return the current run information. I'm not even sure if run-latest.json is even available until the script ends running.

I don't think that it would be a viable alternative to #4732 though, these reports have limited usability when it comes to getting the deployed contracts. They only work if the script deploys a contract directly, as in vm.broadcast(); new MyContract();. Any indirection, like using CREATE3, calling a factory or deploying a contract that itself deploys another contract, makes the broadcast report omit the deployed contracts. The VM knows about all created contracts, so it can obtain all the information and serve it in a specialized cheatcode.

[zerosnacks]

Re-opening as it is significantly different from #4732 and possibly requires a different approach.

You make a good point regarding indirection.

This requires some further exploration in regards to how much context a cheatcode can have in regards to transaction hashes as, to my knowledge, the transactions are collected in order and then executed at the end of the run.

[mds1]

Also related: #3589, can imagine another version that does not wait for the receipt

[CodeSandwich]

Good catch, I think that this issue may be a duplicate of #3589. I'm not sure if forge script can access the TX hashes without explicitly waiting for them, so vm.waitForTransaction could be the the only viable design here.