All: error handling

[gangov]

take this sample contract:

#![no_std]
use soroban_sdk::{contract, contracterror, contractimpl, log, Env};

#[contracterror]
#[derive(Copy, Clone, Debug, Eq, PartialEq, PartialOrd, Ord)]
#[repr(u32)]
pub enum Error {
    Bazz = 1,
}

#[contract]
pub struct ErrorContracts;

#[contractimpl]
impl ErrorContracts {
    pub fn error_enum(env: Env) -> Result<u32, Error> {
        log!(&env, "Error from an enum");
        return Err(Error::Bazz);
    }

    pub fn panic(env: Env) -> Result<u32, Error> {
        panic!("Error from a panic")
    }

    pub fn expect(env: Env) -> Result<u32, Error> {
        let _ = None::<i32>.expect("Error from expect");

        Ok(5u32)
    }
}

currently the error messages that we get from the 3 different calls are as follows:

• error_enum:

2025-01-09T10:39:40.284153Z ERROR soroban_cli::assembled: 0: "AAAAAAAAAAAAAAAAAAAAAgAAAAAAAAADAAAADwAAAAdmbl9jYWxsAAAAAA0AAAAgWXg0OM8MI6zLkjlxSGWoCYOv5CZngttZM
ZeU7dq6nx8AAAAPAAAACmVycm9yX2VudW0AAAAAAAE="
2025-01-09T10:39:40.284225Z ERROR soroban_cli::assembled: 1: "AAAAAAAAAAAAAAABWXg0OM8MI6zLkjlxSGWoCYOv5CZngttZMZeU7dq6nx8AAAACAAAAAAAAAAIAAAAPAAAABWVycm9yAAAAA
AAAAgAAAAAAAAABAAAADgAAADZlc2NhbGF0aW5nIE9rKFNjRXJyb3JUeXBlOjpDb250cmFjdCkgZnJhbWUtZXhpdCB0byBFcnIAAA=="
❌ error: transaction simulation failed: HostError: Error(Contract, #1)
Event log (newest first):
   0: [Diagnostic Event] contract:CBMXQNBYZ4GCHLGLSI4XCSDFVAEYHL7EEZTYFW2ZGGLZJ3O2XKPR6GR3, topics:[error, Error(Contract, #1)], data:"escalating Ok(ScErrorType::Contract) frame-exit to Err"
   1: [Diagnostic Event] topics:[fn_call, CBMXQNBYZ4GCHLGLSI4XCSDFVAEYHL7EEZTYFW2ZGGLZJ3O2XKPR6GR3, error_enum], data:Void

• panic:

2025-01-09T10:40:50.592672Z ERROR soroban_cli::assembled: 0: "AAAAAAAAAAAAAAAAAAAAAgAAAAAAAAADAAAADwAAAAdmbl9jYWxsAAAAAA0AAAAgWXg0OM8MI6zLkjlxSGWoCYOv5CZngttZM
ZeU7dq6nx8AAAAPAAAABXBhbmljAAAAAAAAAQ=="
2025-01-09T10:40:50.592757Z ERROR soroban_cli::assembled: 1: "AAAAAAAAAAAAAAABWXg0OM8MI6zLkjlxSGWoCYOv5CZngttZMZeU7dq6nx8AAAACAAAAAAAAAAIAAAAPAAAABWVycm9yAAAAA
AAAAgAAAAEAAAAGAAAAEAAAAAEAAAACAAAADgAAACdWTSBjYWxsIHRyYXBwZWQ6IFVucmVhY2hhYmxlQ29kZVJlYWNoZWQAAAAADwAAAAVwYW5pYwAAAA=="
❌ error: transaction simulation failed: HostError: Error(WasmVm, InvalidAction)
Event log (newest first):
   0: [Diagnostic Event] contract:CBMXQNBYZ4GCHLGLSI4XCSDFVAEYHL7EEZTYFW2ZGGLZJ3O2XKPR6GR3, topics:[error, Error(WasmVm, InvalidAction)], data:["VM call trapped: UnreachableCodeReached", panic]
   1: [Diagnostic Event] topics:[fn_call, CBMXQNBYZ4GCHLGLSI4XCSDFVAEYHL7EEZTYFW2ZGGLZJ3O2XKPR6GR3, panic], data:Void

• expect:

2025-01-09T10:43:57.766134Z ERROR soroban_cli::assembled: 0: "AAAAAAAAAAAAAAAAAAAAAgAAAAAAAAADAAAADwAAAAdmbl9jYWxsAAAAAA0AAAAgWXg0OM8MI6zLkjlxSGWoCYOv5CZngttZM
ZeU7dq6nx8AAAAPAAAABmV4cGVjdAAAAAAAAQ=="
2025-01-09T10:43:57.766214Z ERROR soroban_cli::assembled: 1: "AAAAAAAAAAAAAAABWXg0OM8MI6zLkjlxSGWoCYOv5CZngttZMZeU7dq6nx8AAAACAAAAAAAAAAIAAAAPAAAABWVycm9yAAAAA
AAAAgAAAAEAAAAGAAAAEAAAAAEAAAACAAAADgAAACdWTSBjYWxsIHRyYXBwZWQ6IFVucmVhY2hhYmxlQ29kZVJlYWNoZWQAAAAADwAAAAZleHBlY3QAAA=="
❌ error: transaction simulation failed: HostError: Error(WasmVm, InvalidAction)
Event log (newest first):
   0: [Diagnostic Event] contract:CBMXQNBYZ4GCHLGLSI4XCSDFVAEYHL7EEZTYFW2ZGGLZJ3O2XKPR6GR3, topics:[error, Error(WasmVm, InvalidAction)], data:["VM call trapped: UnreachableCodeReached", expect]
   1: [Diagnostic Event] topics:[fn_call, CBMXQNBYZ4GCHLGLSI4XCSDFVAEYHL7EEZTYFW2ZGGLZJ3O2XKPR6GR3, expect], data:Void

We should sweep through our codebase and make sure we are using Error enums, instead of panic or expecting