{"record":{"id":"9969b7ef5e78d04c","repo":"facebook/relay","slug":"failed-to-spawn-daemon-process","errorCode":null,"errorMessage":"Failed to spawn daemon process","messagePattern":"Failed to spawn daemon process","errorType":"panic","errorClass":null,"httpStatus":null,"severity":"error","filePath":"compiler/crates/relay-compiler/src/server_daemon.rs","lineNumber":397,"sourceCode":"    args.extend(start_extra_args.iter().cloned());\n\n    let log_path = get_log_file_path(config_path, projects);\n    let log_file = File::options()\n        .create(true)\n        .append(true)\n        .open(&log_path)\n        .expect(\"Failed to open daemon log file\");\n    let log_file_clone = log_file\n        .try_clone()\n        .expect(\"Failed to clone daemon log file handle\");\n\n    let mut child = Command::new(current_exe)\n        .args(&args)\n        .stdin(Stdio::null())\n        .stdout(Stdio::from(log_file))\n        .stderr(Stdio::from(log_file_clone))\n        .spawn()\n        .expect(\"Failed to spawn daemon process\");\n\n    let socket_path = get_socket_path(config_path, projects);\n    let max_attempts = 60;\n    for i in 0..max_attempts {\n        tokio::time::sleep(std::time::Duration::from_secs(1)).await;\n\n        // Detect early daemon-process exit (e.g. invalid project name).\n        if let Some(status) = child\n            .try_wait()\n            .expect(\"Failed to check daemon process status\")\n        {\n            error!(\"Daemon process exited during startup with {status}\");\n            log_daemon_file(&log_path);\n            std::process::exit(1);\n        }\n\n        if send_request(&socket_path, DaemonRequest::Version)\n            .await","sourceCodeStart":379,"sourceCodeEnd":415,"githubUrl":"https://github.com/facebook/relay/blob/668b1b85e06261aa3b58dabfc51f8b5524a70955/compiler/crates/relay-compiler/src/server_daemon.rs#L379-L415","documentation":"Startup panic in start_daemon_process: Command::spawn failed when trying to launch the compiler server as a background child process (current exe re-invoked with the 'server ... start --foreground' argument vector). Spawn failures are environmental — executable permissions, fd limits, or resource exhaustion — not compilation errors.","triggerScenarios":"Thrown at compiler/crates/relay-compiler/src/server_daemon.rs:397 when the library encounters an invalid state.","commonSituations":"See trigger scenarios.","solutions":["Verify the current executable is still present and executable (it may have been replaced mid-run by a rebuild)","Raise process/fd limits if the system refuses to fork or allocate stdio pipes","Check overall system memory and process counts; retry after freeing resources"],"exampleFix":null,"handlingStrategy":"retry","validationCode":null,"typeGuard":null,"tryCatchPattern":null,"preventionTips":[],"tags":[],"backgroundTag":null,"analyzedSha":"668b1b85e06261aa3b58dabfc51f8b5524a70955","analyzedAt":"2026-09-02T19:57:20.783Z","contentChangedAt":null,"schemaVersion":2},"datasetVersion":"2026-09-10T02:17:09.455Z"}