affaan-m/ECC · error · anyhow::Error

DB writer acknowledgement dropped

Error message

DB writer acknowledgement dropped

What it means

A DB write message was enqueued and awaited, but the writer task dropped the oneshot acknowledgement sender before replying — i.e. the writer stopped while processing this request. Whether the write landed is unknown; treat the DB writer as failed.

Source

Thrown at ecc2/src/session/runtime.rs:76

    }

    async fn touch_heartbeat(&self) -> Result<()> {
        self.send(|ack| DbMessage::TouchHeartbeat { ack }).await
    }

    async fn send<F>(&self, build: F) -> Result<()>
    where
        F: FnOnce(oneshot::Sender<DbAck>) -> DbMessage,
    {
        let (ack_tx, ack_rx) = oneshot::channel();
        self.tx
            .send(build(ack_tx))
            .map_err(|_| anyhow::anyhow!("DB writer channel closed"))?;

        match ack_rx.await {
            Ok(Ok(())) => Ok(()),
            Ok(Err(error)) => Err(anyhow::anyhow!(error)),
            Err(_) => Err(anyhow::anyhow!("DB writer acknowledgement dropped")),
        }
    }
}

fn run_db_writer(db_path: PathBuf, session_id: String, mut rx: mpsc::UnboundedReceiver<DbMessage>) {
    let (opened, open_error) = match StateStore::open(&db_path) {
        Ok(db) => (Some(db), None),
        Err(error) => (None, Some(error.to_string())),
    };

    while let Some(message) = rx.blocking_recv() {
        match message {
            DbMessage::UpdateState { state, ack } => {
                let result = match opened.as_ref() {
                    Some(db) => db
                        .update_state(&session_id, &state)
                        .map_err(|error| error.to_string()),
                    None => Err(open_error

View on GitHub (pinned to 06c5e118c4)

Solutions

1. Check whether the writer task panicked or was cancelled before acknowledging.
2. Add logging around writer shutdown to find the drop cause.

When it happens

Trigger: Thrown at ecc2/src/session/runtime.rs:76 when the library encounters an invalid state.

Common situations: See trigger scenarios.

AI-assisted analysis of affaan-m/ECC@06c5e118c4 (2026-08-18). Data as JSON: /api/errors/7e3b09c68c633b99. Report an issue: GitHub.