facebook/flow · error

failed to flush status

Error message

failed to flush status

What it means

Raised by print_status when stderr.flush() fails after writing the status message. The write may have been buffered by the locked StderrLock, and the flush surfaces any deferred I/O error (EPIPE, ENOSPC, closed descriptor). The expect panics because a failed flush means the status output was not actually delivered.

Source

Thrown at rust_port/crates/flow_commands_connect/src/command_connect.rs:54

    pub show_progress: bool,
    pub flowconfig_name: &'a str,
    pub rerun_on_mismatch: bool,
}

fn print_status(env: &Env<'_>, message: &str) {
    if env.quiet {
        return;
    }

    let stderr = std::io::stderr();
    let mut stderr = stderr.lock();
    if env.show_progress && stderr.is_terminal() {
        write!(stderr, "{}: {}", message, flow_utils_tty::spinner(false))
            .expect("failed to write spinner status");
    } else {
        writeln!(stderr, "{}", message).expect("failed to write status");
    }
    stderr.flush().expect("failed to flush status");
}

fn arg(name: &str, value: Option<&str>, arr: &mut Vec<String>) {
    if let Some(value) = value {
        arr.push(name.to_string());
        arr.push(value.to_string());
    }
}

fn flag(name: &str, value: bool, arr: &mut Vec<String>) {
    if value {
        arr.push(name.to_string());
    }
}

// Starts up a flow server by literally calling flow start
fn start_flow_server(env: &Env) -> Result<(), (String, flow_common_exit_status::FlowExitStatus)> {
    let Env {

View on GitHub (pinned to 5c86586199)

Solutions

1. Reattach to a valid stderr (live terminal or writable file) and rerun the command.
2. Check and free disk space if stderr is file-redirected.
3. Ignore the broken output stream by rerunning with --quiet / progress disabled.
4. Change the library to treat flush errors as non-fatal (best-effort logging).

Example fix

// before
stderr.flush().expect("failed to flush status");
// after
let _ = stderr.flush(); // best-effort; status output is not critical

use std::io::Write;
fn flush_ok() -> bool { std::io::stderr().flush().is_ok() }

fn stderr_flushable() -> bool {
    use std::io::Write;
    std::io::stderr().flush().is_ok()
}

let result = std::panic::catch_unwind(run_connect);
if result.is_err() {
    eprintln!("flush failed mid-run: check stderr target (EPIPE/ENOSPC)");
}

When it happens

Trigger: connect_rec or handle_missing_server calls print_status; the writeln! succeeds into the buffer, but flushing to the underlying stderr descriptor fails — typically broken pipe on a detached terminal or ENOSPC on a redirected log file.

Common situations: Long-running connect loops where the terminal/SSH session dies mid-run; stderr redirected to a filesystem that fills up during the run; container runtimes that close the log stream.

Related errors

• failed to flush spinner status
• failed to write spinner status
• failed to write status
• failed to flush cli errors
• failed to clear spinner line

AI-assisted analysis of facebook/flow@5c86586199 (2026-09-08). Data as JSON: /api/errors/7222c85649642200. Report an issue: GitHub.