linera-io/linera-protocol · error

Expected an `ExecutionError`. Got: {chain_error:#?}

Error message

Expected an `ExecutionError`. Got: {chain_error:#?}

What it means

The second stage of expect_execution_error: the WorkerError was a ChainError, but the inner chain error is not the ExecutionError variant (e.g. an arithmetic/validity error, a view error, or another ChainError kind). The panic prints the full chain_error debug so the actual variant is identifiable. A third assertion (context == expected_context) follows after this stage.

Source

Thrown at linera-core/src/worker.rs:538

            error => Self::ChainError(Box::new(error)),
        }
    }
}

#[cfg(with_testing)]
impl WorkerError {
    /// Returns the inner [`ExecutionError`] in this error.
    ///
    /// # Panics
    ///
    /// If this is not caused by an [`ExecutionError`].
    pub fn expect_execution_error(self, expected_context: ChainExecutionContext) -> ExecutionError {
        let WorkerError::ChainError(chain_error) = self else {
            panic!("Expected an `ExecutionError`. Got: {self:#?}");
        };

        let ChainError::ExecutionError(execution_error, context) = *chain_error else {
            panic!("Expected an `ExecutionError`. Got: {chain_error:#?}");
        };

        assert_eq!(context, expected_context);

        *execution_error
    }
}

type ChainWorkerArc<S> = Arc<tokio::sync::RwLock<ChainWorkerState<S>>>;
type ChainWorkerWeak<S> = std::sync::Weak<tokio::sync::RwLock<ChainWorkerState<S>>>;
type ChainWorkerFuture<S> = Shared<oneshot::Receiver<ChainWorkerWeak<S>>>;

/// Each map entry is a `Shared<oneshot::Receiver<Weak<...>>>`:
///
/// - `peek()` returns `None` while a task is loading the worker from storage.
/// - `peek()` returns `Some(Ok(weak))` once the worker is loaded.
/// - `peek()` returns `Some(Err(_))` if loading failed (sender dropped).
///

View on GitHub (pinned to 6c226ddcb3)

Solutions

1. Read the {chain_error:#?} dump and either match that variant directly or fix the fixture so execution actually reaches the failing operation.
2. Verify the expected ChainExecutionContext too — the following assert_eq!(context, expected_context) is a common next failure.
3. Prefer explicit matches on the expected error shape in tests instead of blanket expect_* helpers when the error layer is uncertain.

Example fix

// before
let exec = err.expect_execution_error(ChainExecutionContext::Query); // panics on ChainError::ArithError

// after
let WorkerError::ChainError(chain_err) = err else { panic!("expected chain error") };
match *chain_err {
    ChainError::ExecutionError(exec, ctx) => { assert_eq!(ctx, ChainExecutionContext::Query); /* ... */ }
    other => panic!("unexpected: {other:?}"),
}

// Rust
if !matches!(&err, WorkerError::ChainError(inner) if matches!(**inner, ChainError::ExecutionError(_, _))) {
    // handle the actual chain error variant instead of unwrapping
}

fn chain_error_is_execution(err: &WorkerError) -> bool {
    matches!(err, WorkerError::ChainError(inner) if matches!(&**inner, ChainError::ExecutionError(..)))
}

let WorkerError::ChainError(chain_err) = err else { panic!("expected chain error") };
match *chain_err {
    ChainError::ExecutionError(exec, ctx) => { assert_eq!(ctx, expected_ctx); /* assert on exec */ }
    other => panic!("unexpected chain error: {other:?}"),
}

When it happens

Trigger: In tests: the worker wrapped a non-execution ChainError — certificate validation failures, view/bucket errors, chain-state problems — where the test expected user-code execution to fail. The {chain_error:#?} output names the true variant.

Common situations: Tests asserting application-level execution failures that actually fail earlier at consensus/state level; changes in error taxonomy moving a case from ChainError::ExecutionError to a sibling variant; fixtures leaving the chain in a state that errors before operations run.

Related errors

• Expected an `ExecutionError`. Got: {self:#?}
• Failed to obtain a port
• {}: got non-zero error code {}
• owner should be different from spender
• invalid block export configuration: {message}

AI-assisted analysis of linera-io/linera-protocol@6c226ddcb3 (2026-08-22). Data as JSON: /api/errors/cfb3781966eece98. Report an issue: GitHub.