{"record":{"id":"8651aa35cf76df1b","repo":"astrid-runtime/astrid","slug":"read-detached-fuse-stderr-during-sink-handoff","errorCode":null,"errorMessage":"read detached FUSE stderr during sink handoff","messagePattern":"read detached FUSE stderr during sink handoff","errorType":"exception","errorClass":null,"httpStatus":null,"severity":"error","filePath":"crates/astrid-storage-provider-fuse/src/main.rs","lineNumber":623,"sourceCode":"            if read == 0 {\n                break;\n            }\n            let remaining = (MAX_FUSE_STDERR_BYTES + 1).saturating_sub(bytes.len());\n            bytes.extend_from_slice(&buffer[..read.min(remaining)]);\n        }\n        std::io::Result::Ok(bytes)\n    });\n    let startup = read_service_startup(&mut child, launch, control_path).await;\n    match startup {\n        Ok(ready) => {\n            match tokio::time::timeout(Duration::from_secs(1), &mut stderr_task).await {\n                Ok(Ok(Ok(_))) => require_service_running_after_handoff(&mut child)\n                    .await\n                    .map(|()| ready),\n                Ok(Ok(Err(error))) => {\n                    let _ = child.kill().await;\n                    let status = child.wait().await;\n                    Err(anyhow::Error::new(error)\n                        .context(\"read detached FUSE stderr during sink handoff\")\n                        .context(format!(\"detached FUSE service status: {status:?}\")))\n                },\n                Ok(Err(error)) => {\n                    let _ = child.kill().await;\n                    let status = child.wait().await;\n                    Err(anyhow::anyhow!(\"detached FUSE stderr drain failed: {error}\")\n                        .context(format!(\"detached FUSE service status: {status:?}\")))\n                },\n                Err(_) => {\n                    stderr_task.abort();\n                    let _ = child.kill().await;\n                    let status = child.wait().await;\n                    Err(anyhow::anyhow!(\"detached FUSE stderr sink handoff timed out\")\n                        .context(format!(\"detached FUSE service status: {status:?}\")))\n                },\n            }\n        },","sourceCodeStart":605,"sourceCodeEnd":641,"githubUrl":"https://github.com/astrid-runtime/astrid/blob/affd8760f44190dbdfbec23403f4c4b642c33112/crates/astrid-storage-provider-fuse/src/main.rs#L605-L641","documentation":"When spawning the detached FUSE service, a handoff task reads the child's stderr through a sink after detachment. If that task returns an error, main kills the child, waits for its exit status, and wraps the error with this context plus the child's exit status for diagnostics.","triggerScenarios":"The stderr-sink handoff future completes with Err — the detached FUSE service wrote/closed stderr abnormally or the sink task failed — while main was waiting on Ok(Ok(Err(error))) from the select/join of readiness and handoff futures.","commonSituations":"The FUSE service crashes during startup and emits a panic trace to stderr; stderr pipe is closed unexpectedly; handoff task itself errors while relaying stderr.","solutions":["Read the detached FUSE service status printed in the error context and fix the underlying service startup failure first","Check the FUSE provider logs/stderr captured by the sink for the root-cause panic or message","Verify the FUSE mount point is available and the provider binary is runnable before spawning","Re-run in the foreground (non-detached mode) to see the service's stderr directly"],"exampleFix":null,"handlingStrategy":"try-catch","validationCode":"// pre-flight before spawning the detached FUSE service\nassert!(Path::new(&fuse_binary).exists(), \"FUSE provider binary missing\");\nassert!(Path::new(&mountpoint).exists(), \"mountpoint missing\");\nlet status = Command::new(&fuse_binary).arg(\"--version\").status()?;\nassert!(status.success(), \"FUSE provider not runnable\");","typeGuard":null,"tryCatchPattern":"match result {\n    Err(err) if err.to_string().contains(\"read detached FUSE stderr during sink handoff\") => {\n        eprintln!(\"FUSE service failed during startup handoff: {err:#}\");\n        eprintln!(\"re-run in foreground to capture stderr directly\");\n    }\n    other => other?,\n}","preventionTips":["Test the FUSE provider in foreground mode before enabling detached mode","Ensure mountpoint exists and is writable before spawn","Capture and persist the stderr sink output for post-mortem diagnostics"],"tags":["process","fuse","spawn","stderr"],"backgroundTag":"child-process-handoff-failed","analyzedSha":"affd8760f44190dbdfbec23403f4c4b642c33112","analyzedAt":"2026-09-09T21:28:12.402Z","contentChangedAt":"2026-09-09T21:28:12.402Z","schemaVersion":2},"datasetVersion":"2026-09-17T15:17:12.973Z"}