zed-industries/zed · error

Failed to unwrap Mutex

Error message

Failed to unwrap Mutex

What it means

After unwrapping the Arc, run_prediction locks the example's Mutex via into_inner; it fails because the mutex was still locked elsewhere (a task holding the guard leaked or panicked), so exclusive access cannot be obtained.

Source

Thrown at crates/edit_prediction_cli/src/predict.rs:337

        if ix == repetition_count - 1 {
            let (info, style) = if has_prediction {
                ("predicted", InfoStyle::Normal)
            } else {
                ("no prediction", InfoStyle::Warning)
            };
            step_progress.set_info(info, style);
        }
    }

    ep_store.update(&mut cx, |store, _| {
        store.remove_project(&state.project);
    });
    debug_task.await?;

    *example = Arc::into_inner(updated_example)
        .ok_or_else(|| anyhow::anyhow!("Failed to unwrap Arc"))?
        .into_inner()
        .map_err(|_| anyhow::anyhow!("Failed to unwrap Mutex"))?;
    Ok(())
}

async fn predict_teacher(
    example: &mut Example,
    backend: TeacherBackend,
    batched: bool,
    repetition_count: usize,
    cache_only: bool,
    step_progress: &crate::progress::StepProgress,
) -> anyhow::Result<()> {
    match backend {
        TeacherBackend::Sonnet45 | TeacherBackend::Sonnet46 => {
            predict_anthropic(
                example,
                backend,
                batched,
                repetition_count,

View on GitHub (pinned to f4178619ac)

Solutions

1. Find and fix the task that retains the mutex guard (often a panicked worker)
2. Ensure guards are scoped so they drop before prediction finishes

When it happens

Trigger: Thrown at crates/edit_prediction_cli/src/predict.rs:337 when the library encounters an invalid state.

Common situations: See trigger scenarios.

AI-assisted analysis of zed-industries/zed@f4178619ac (2026-08-20). Data as JSON: /api/errors/1305d455c3333273. Report an issue: GitHub.