{"record":{"id":"8ca5a7426b2f6822","repo":"xai-org/grok-build","slug":"error-8ca5a7","errorCode":null,"errorMessage":"{error}","messagePattern":"\\{error\\}","errorType":"exception","errorClass":null,"httpStatus":null,"severity":"error","filePath":"crates/codegen/xai-grok-pager-render/src/render/draw.rs","lineNumber":286,"sourceCode":"            let _ = h.join();\n        }\n    }\n}\nfn write_payload(\n    writer: &mut impl Write,\n    payload: &WriterPayload,\n    sync: &WriterSync,\n) -> std::io::Result<()> {\n    match writer\n        .write_all(&payload.data)\n        .and_then(|()| writer.flush())\n    {\n        Ok(()) => {\n            sync.mark_written(payload.sequence);\n            Ok(())\n        }\n        Err(error) => {\n            sync.mark_failed(std::io::Error::new(error.kind(), error.to_string()));\n            Err(error)\n        }\n    }\n}\n/// Spawn a background OS thread that writes frame data to stderr.\n///\n/// Returns the frame sender, shared writer state, completion-event receiver,\n/// and the thread handle that must be joined during terminal teardown.\npub fn spawn_writer_thread() -> (\n    WriterSender,\n    WriterSync,\n    tokio::sync::mpsc::UnboundedReceiver<WriterEvent>,\n    WriterThread,\n) {\n    let (tx, rx) = mpsc::channel::<WriterPayload>();\n    let (event_tx, event_rx) = tokio::sync::mpsc::unbounded_channel();\n    let sync = WriterSync::with_event_sender(event_tx);\n    let thread_sync = sync.clone();","sourceCodeStart":268,"sourceCodeEnd":304,"githubUrl":"https://github.com/xai-org/grok-build/blob/bc7f02eddd3d84085849dc19ed216f11c23b0571/crates/codegen/xai-grok-pager-render/src/render/draw.rs#L268-L304","documentation":"write_payload propagates the underlying io error from the writer thread's stderr write. Before returning Err it records the failure via sync.mark_failed (preserving kind and message, rendered into the message as {error}), so pending sequence accounting marks the frame as failed. The displayed message is simply the original io error text.","triggerScenarios":"Calling write_payload (invoked from spawn_writer_thread's loop) when writing the frame to stderr fails, e.g. stderr closed, EBADF, or the tty disappeared.","commonSituations":"Terminal/SSH session disconnecting mid-render; output redirection to a closed pipe; pager running after the parent process closed stderr.","solutions":["Verify stderr is a valid, open fd before rendering (avoid running after the parent closes it)","Handle the propagated io error and tear down the pager session gracefully","If stderr is redirected, redirect to a live sink (file or pty) instead of a closed pipe","Check mark_failed consumers to surface the failure to users instead of hanging on acknowledgements"],"exampleFix":"// before\nwriter.write_payload(frame)?; // raw io error propagates\n// after\nif let Err(e) = writer.write_payload(frame) {\n    eprintln!(\"render failed ({}): stopping pager\", e);\n    return Err(e);\n}","handlingStrategy":"try-catch","validationCode":"// ensure stderr is writable before spawning the renderer\nif std::io::stderr().write_all(b\"\").is_err() {\n    eprintln!(\"stderr unavailable; terminal rendering disabled\");\n    return;\n}","typeGuard":null,"tryCatchPattern":"match writer.write_payload(payload) {\n    Err(e) => {\n        eprintln!(\"frame write failed ({}): aborting render\", e);\n        session.teardown();\n    }\n    Ok(()) => {}\n}","preventionTips":["Do not close stderr while the pager is rendering","Avoid redirecting stderr to pipes that the parent may close","Surface mark_failed state to users instead of waiting on acks","Test rendering over SSH/disconnect scenarios"],"tags":["terminal","io","render","stderr"],"backgroundTag":"broken-pipe","analyzedSha":"bc7f02eddd3d84085849dc19ed216f11c23b0571","analyzedAt":"2026-08-31T04:59:42.031Z","schemaVersion":2},"datasetVersion":"2026-08-31T09:17:48.483Z"}