facebook/relay · error

Failed to get current exe path

Error message

Failed to get current exe path

What it means

Startup panic in start_daemon_process: the compiler server could not determine the path of its own executable via std::env::current_exe(). The daemon is relaunched by re-invoking the current binary, so without the exe path the watchdog cannot spawn the background server process and aborts immediately.

Source

Thrown at compiler/crates/relay-compiler/src/server_daemon.rs:370

/// to come up. The child is invoked as
/// `<current_exe> server <extra_args> --project <p>... start --foreground <start_extra_args>`,
/// with stdout/stderr redirected to the daemon log file derived from
/// `config_path` and `projects`.
///
/// Polls the daemon socket once per second for up to 60 seconds. Exits the
/// caller process with code 1 if the child exits during startup or fails
/// to bind the socket within the timeout. `extra_args` is inserted before
/// the project flags so callers can pass `Server`-subcommand-level options
/// (e.g. the OSS relay-bin passes `--config <path>`). `start_extra_args`
/// is appended after `--foreground` so callers can pass `Start`-subcommand-
/// level options (e.g. `--initial-import-state <path>`).
pub async fn start_daemon_process(
    config_path: &Path,
    projects: &[String],
    extra_args: &[String],
    start_extra_args: &[String],
) {
    let current_exe = std::env::current_exe().expect("Failed to get current exe path");
    let mut args = vec!["server".to_string()];
    args.extend(extra_args.iter().cloned());
    for project in projects {
        args.push("--project".to_string());
        args.push(project.clone());
    }
    args.push("start".to_string());
    args.push("--foreground".to_string());
    args.extend(start_extra_args.iter().cloned());

    let log_path = get_log_file_path(config_path, projects);
    let log_file = File::options()
        .create(true)
        .append(true)
        .open(&log_path)
        .expect("Failed to open daemon log file");
    let log_file_clone = log_file
        .try_clone()

View on GitHub (pinned to 668b1b85e0)

Solutions

1. On Linux, check that /proc is mounted and the exe entry is readable
2. Ensure the binary wasn't deleted or replaced while running (re-exec requires the original path to exist)
3. Run the compiler from a stable installed location rather than a temporary build artifact that gets cleaned up

When it happens

Trigger: Thrown at compiler/crates/relay-compiler/src/server_daemon.rs:370 when the library encounters an invalid state.

Common situations: See trigger scenarios.

AI-assisted analysis of facebook/relay@668b1b85e0 (2026-09-02). Data as JSON: /api/errors/036bd79e9a1d56eb. Report an issue: GitHub.