ruvnet/RuView · error

cannot write {}: {e}

Error message

cannot write {}: {e}

What it means

std::fs::write failed to persist the pretty-printed enrollment JSON to --output at the end of a completed enroll session. OS-level io::Error: missing parent directory, permissions, disk full, or the path naming a directory. The interactive anchor captures succeeded but the features exist only in memory, so a write failure means re-enrolling.

Source

Thrown at v2/crates/wifi-densepose-cli/src/room.rs:208

        }
    }

    if session.is_complete() {
        session.apply(EnrollmentEvent::Completed { at: now_unix() });
    }
    let (got, total) = session.progress();
    let data = EnrollmentData {
        room_id: args.room_id.clone(),
        baseline_id,
        fs_hz: args.fs_hz,
        anchors: features,
        session,
    };
    std::fs::write(
        &args.output,
        serde_json::to_string_pretty(&data).map_err(|e| anyhow::anyhow!("serialize: {e}"))?,
    )
    .map_err(|e| anyhow::anyhow!("cannot write {}: {e}", args.output))?;
    eprintln!(
        "\n[enroll] done: {got}/{total} anchors accepted → {} (next: `train-room`)",
        args.output
    );
    Ok(())
}

// ---------------------------------------------------------------------------
// train-room
// ---------------------------------------------------------------------------

/// Arguments for `train-room`.
#[derive(Args, Debug, Clone)]
pub struct TrainRoomArgs {
    /// Enrollment file from `enroll`.
    #[arg(long, default_value = "./enrollment.json")]
    pub enrollment: String,
    /// Output specialist-bank file.

View on GitHub (pinned to 4685618388)

Solutions

1. Create the parent directory before starting enroll (mkdir -p)
2. Fix permissions/ownership on the output directory
3. Free disk space or choose another --output path
4. Confirm the path is a file location, then re-run the enrollment

Example fix

// before
std::fs::write(
    &args.output,
    serde_json::to_string_pretty(&data).map_err(|e| anyhow::anyhow!("serialize: {e}"))?,
)
.map_err(|e| anyhow::anyhow!("cannot write {}: {e}", args.output))?;

// after
if let Some(parent) = std::path::Path::new(&args.output).parent() {
    std::fs::create_dir_all(parent)
        .map_err(|e| anyhow::anyhow!("cannot create {}: {e}", parent.display()))?;
}
std::fs::write(
    &args.output,
    serde_json::to_string_pretty(&data).map_err(|e| anyhow::anyhow!("serialize: {e}"))?,
)
.map_err(|e| anyhow::anyhow!("cannot write {}: {e}", args.output))?;

fn enrollment_output_ok(path: &str) -> bool {
    let p = std::path::Path::new(path);
    p.parent().map(|d| d.is_dir()).unwrap_or(true)
        && !p.is_dir()
        && std::fs::OpenOptions::new().write(true).create(true).truncate(false).open(p).is_ok()
}

When it happens

Trigger: --output pointing into a nonexistent directory; unwritable or foreign-owned target; disk full; --output naming an existing directory.

Common situations: Fresh directories never created; running as a different user; full disks in constrained environments — especially costly here because the whole interactive session must be repeated.

Related errors

• cannot write {output}: {e}
• cannot read {}: {e} — run `enroll` first
• cannot read {path}: {e}
• data_dir not accessible {}: {e}
• parent not accessible {}: {e}

AI-assisted analysis of ruvnet/RuView@4685618388 (2026-08-16). Data as JSON: /api/errors/7f059039b3f6bcdc. Report an issue: GitHub.