The script for the ` `-variable exited unsuccessfully

Error message

The script for the `{}`-variable exited unsuccessfully

What it means

run_poll_once executes a polling script variable's command once and returns its output as a DynVal. For a shell command source, a non-zero exit is converted into this error (with a contextual warning naming the var and command); for a function source, any returned error is propagated.

Solutions

Run the command manually and fix the non-zero exit condition
Make the script resilient: append `|| echo fallback` or handle expected failures inside the script
Suppress stderr / normalize exit codes for commands that legitimately report via exit codes

Example fix

// before
(defpoll net :interval "5s" "curl -fsSL https://example.com/health")  ; fails when offline

// after
(defpoll net :interval "5s" "curl -fsSL https://example.com/health || echo offline")

Defensive patterns

Strategy: try-catch

Validate before calling

# sanity-check the poll command exits 0
bash -c "$(grep -oP '(?<=:command ")[^"]+' ~/.config/eww/eww.yuck)" || echo fix

Try / catch

match script_var_handler::run_poll_once(&var) {
    Ok(v) => update(v),
    Err(e) => { log::warn!("poll failed: {e:#}"); keep_last_value(); }
}

Prevention

Make poll scripts idempotent and always exit 0 on expected failures
Redirect stderr and emit fallback text
Avoid transient-network commands without `|| echo fallback`

When it happens

Trigger: The poll loop (or an explicit `eww poll` via force_poll_variable) invokes run_poll_once and the var's shell command exits non-zero, or its Rust function source returns Err.

Common situations: Script depends on a missing binary; intermittent failures (network check, acpi absent); quoting/whitespace bugs in the command; command returns non-zero on transient conditions.

Related errors

AI-assisted analysis of elkowar/eww@48f5aa8b37 (2026-09-08). Data as JSON: /api/errors/82a4dd017bcbf70e. Report an issue: GitHub.

Appendix: source

Thrown at crates/eww/src/script_var_handler.rs:202

        });
    }

    fn stop_for_variable(&mut self, name: &VarName) {
        if let Some(token) = self.poll_handles.remove(name) {
            log::debug!("stopped poll var {}", name);
            token.cancel()
        }
    }

    fn stop_all(&mut self) {
        self.poll_handles.drain().for_each(|(_, token)| token.cancel());
    }
}

pub fn run_poll_once(var: &PollScriptVar) -> Result<DynVal> {
    match &var.command {
        VarSource::Shell(span, command) => {
            script_var::run_command(command).map_err(|e| anyhow!(create_script_var_failed_warn(*span, &var.name, &e.to_string())))
        }
        VarSource::Function(x) => x().map_err(|e| anyhow!(e)),
    }
}

impl Drop for PollVarHandler {
    fn drop(&mut self) {
        self.stop_all();
    }
}

struct ListenVarHandler {
    evt_send: UnboundedSender<DaemonCommand>,
    listen_process_handles: HashMap<VarName, cancellation::AwaitableCancelationSender>,
}

impl ListenVarHandler {
    fn new(evt_send: UnboundedSender<DaemonCommand>) -> Result<Self> {

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