💡 [REQUEST] - Access instruction Return value in Fuzz Tests

[IaroslavMazur]

Summary

Problem

Currently, Trident's execute_transaction method doesn't allow accessing the Result<T> value returned by the executing instruction.

This limitation is especially troublesome in the context of View instructions, as they don't change the state of the blockchain - and, therefore, their Result<T> value is the only method there is to test the correctness of the respective instructions.

Current Workaround

None

Basic Example

let result = self.trident.execute_transaction(&mut my_tx, Some("MyTx"));
let returned_value = result.unwrap();

Drawbacks

None

Unresolved questions

No response

Implementation PR

No response

Reference Issues

No response

[lukacan]

Yes, good idea, we will have a look at it !

[IaroslavMazur]

Yes, good idea, we will have a look at it !

Looking forward to this!

[IaroslavMazur]

Hey, @lukacan, it looks like TransactionResult still doesn't expose instruction return data. The underlying SVM already captures it in ExecutedTransaction.execution_details.return_data (as Option<TransactionReturnData>), but it's never forwarded into TransactionResult::new(), so it gets silently dropped.

Right now, we're working around this by parsing the "Program return: <program_id> <base64_data>" string from transaction logs and manually base64-decoding the bytes. It works, but it's fragile, as it depends on the exact log format and breaks if that ever changes.

It seems like #399 addressed part of this by adding logs and timestamp to TransactionResult, but the return data was left out. The fix should be to pass return_data through to TransactionResult and add a get_return_data() getter, similar to how get_transaction_timestamp() already works.

[lukacan]

Would it be helpful if it were in format pub data: Vec<u8>,?

[IaroslavMazur]

Would it be helpful if it were in format pub data: Vec<u8>,?

As long as the result also contains the id of the program, this would work, yes!

Here's what I mean, more precisely:

// On TransactionResult:
  pub fn return_data(&self) -> Option<ReturnData>

  pub struct ReturnData {
      pub program_id: Pubkey,
      pub data: Vec<u8>,
  }

[lukacan]

Yes, will prepare

[lukacan]

Hello @IaroslavMazur , just created PR 456, will that work ? :)

[IaroslavMazur]

Hello @IaroslavMazur , just created PR 456, will that work ? :)

Yes, that should work.

Thank you for listening to user feedback!