loco-rs/loco · error

memory service must build with success

Error message

memory service must build with success

What it means

The in-memory storage driver constructs an OpenDAL `Operator` over a default `Memory` service. Because `Memory::default()` has no configurable fields that can be wrong, this `expect` can essentially only fire if the OpenDAL builder itself fails internally (library bug or version mismatch). It is an invariant guard: memory storage must always build.

Solutions

1. Run `cargo update -p opendal` / check `cargo tree -i opendal` to ensure a single compatible opendal version matching loco's (0.58-style API)
2. Restore the default loco dependency versions for opendal if they were patched
3. Report an upstream opendal bug if the memory builder fails with default settings

// Ensure a single compatible opendal in the tree before relying on drivers
// $ cargo tree -i opendal  # must show exactly one version
std::process::Command::new("cargo")
    .args(["tree", "-i", "opendal"])
    .status()?;

// Guard the construction in tests/tools
let driver = std::panic::catch_unwind(loco_rs::storage::drivers::mem::new)
    .map_err(|_| anyhow::anyhow!("memory storage driver failed; check opendal version"))?;

When it happens

Trigger: Calling `loco_rs::storage::drivers::mem::new()` with an opendal crate version mismatch in the dependency tree (e.g. two opendal major versions), or an opendal internal builder error on `Memory::default()`.

Common situations: Cargo dependency resolution pulling an incompatible opendal after an upgrade; vendored/patched builds where the memory service feature is disabled or broken.

Understand the failure class

Background: "This is a bug, please report it": internal invariant violations, unreachable panics, and SNH errors explained — this error's family across 47 libraries.

Related errors

• fs service should build with success
• failed to install signal handler
• logger initialization failed
• create cleanup runtime
• db cleanup thread panicked

AI-assisted analysis of loco-rs/loco@23639d1e36 (2026-09-12). Data as JSON: /api/errors/c3c457163662c33c. Report an issue: GitHub.

Appendix: source

Thrown at src/storage/drivers/mem.rs:21

use super::StoreDriver;
use crate::storage::drivers::opendal_adapter::OpendalAdapter;

/// Create new in-memory storage.
///
/// # Examples
///```
/// use loco_rs::storage::drivers::mem;
/// let mem_storage = mem::new();
/// ```
///
/// # Panics
///
/// Panics if the memory service built failed.
#[must_use]
pub fn new() -> Box<dyn StoreDriver> {
    // opendal 0.58: Operator::new returns a finished Operator (no .finish()).
    Box::new(OpendalAdapter::new(
        Operator::new(Memory::default()).expect("memory service must build with success"),
    ))
}

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