t8y2/dbx · error

checked one driver

Error message

checked one driver

What it means

tar_zstd_driver_package_info first validates that a tar.zst offline driver package contains exactly one driver, then calls registry.drivers.iter().next().expect("checked one driver") to extract it. The expect relies on the length check immediately above; it can only panic if the validation and extraction are separated or the length check is bypassed, which would be a code-invariant break.

Source

Thrown at crates/dbx-core/src/agent_service.rs:2588

                InstalledDriver {
                    version: info.version.clone(),
                    installed_at: chrono::Utc::now().to_rfc3339(),
                    jre: info.jre.clone(),
                },
            );
        })?;
    }
    am.stop_daemon_by_key(&info.db_type).await;
    result.drivers_installed.push(info.db_type);
    Ok(result)
}

fn tar_zstd_driver_package_info(package_path: &Path) -> Result<TarZstdDriverPackageInfo, String> {
    let registry = read_registry_from_tar_zstd(package_path)?;
    if registry.drivers.len() != 1 {
        return Err("A tar.zst driver package must contain exactly one driver".to_string());
    }
    let (db_type, driver) = registry.drivers.iter().next().expect("checked one driver");
    validate_offline_driver_key(db_type)?;
    let current_platform = AgentManager::current_platform();
    let (native_platform, native_artifact) = if let Some(artifact) = driver.native.get(current_platform) {
        (Some(current_platform.to_string()), Some(artifact))
    } else if driver.native.len() == 1 {
        let (platform, artifact) = driver.native.iter().next().expect("checked one native platform");
        (Some(platform.clone()), Some(artifact))
    } else {
        (None, None)
    };
    let jar_artifact = usable_driver_jar(driver);
    let (kind, artifact) = match (native_artifact, jar_artifact) {
        (Some(_), Some(_)) => {
            return Err("A tar.zst driver package must contain exactly one driver artifact".to_string());
        }
        (Some(artifact), None) => (DriverArtifactKind::Native, artifact),
        (None, Some(artifact)) => (DriverArtifactKind::Jar, artifact),
        (None, None) if !driver.native.is_empty() => {

View on GitHub (pinned to c0390bff16)

Solutions

1. Keep the len()!=1 guard immediately before extraction; never call iter().next() without it.
2. If you need a multi-driver tar.zst, use the registry-import path that supports multiple drivers instead of this single-driver helper.
3. For robustness, use a match on registry.drivers.len() returning a Result rather than expect.
4. Rebuild/repackage the offline driver so the archive contains exactly one driver.

Example fix

// before
let (db_type, driver) = registry.drivers.iter().next().expect("checked one driver");
// after
let Some((db_type, driver)) = registry.drivers.into_iter().next() else {
    return Err("A tar.zst driver package must contain exactly one driver".to_string());
};

// before importing a tar.zst driver package, check the registry layout
let registry = read_registry_from_tar_zstd(path)?;
if registry.drivers.len() != 1 {
    return Err(format!(
        "package must contain exactly one driver, found {}",
        registry.drivers.len()
    ));
}

fn single_driver(registry: &DriverRegistry) -> Option<(&str, &OfflineDriver)> {
    if registry.drivers.len() == 1 { registry.drivers.iter().next() } else { None }
}

let Some((db_type, driver)) = registry.drivers.iter().next() else {
    return Err("A tar.zst driver package must contain exactly one driver".to_string());
};

When it happens

Trigger: Programmatically impossible when the preceding `if registry.drivers.len() != 1 { return Err(...) }` guard is intact; it panics only if the guard is removed/reordered during refactoring or iter().next() is called on a mutated map. The real user-facing failure from this area is the Err "A tar.zst driver package must contain exactly one driver".

Common situations: Users building offline driver packages with zero or multiple drivers hit the Err message; developers refactoring the parsing function may turn the silent guard into a panic; packages built by older tooling versions with different layouts.

Related errors

• checked one native platform
• a batch cancellation token is always available
• driver token registered
• a cancellation token is always available
• root count checked above

AI-assisted analysis of t8y2/dbx@c0390bff16 (2026-09-05). Data as JSON: /api/errors/a2704bfa1c344483. Report an issue: GitHub.