What causes "panic during siyuan.client.fetch: %v" in siyuan-note/siyuan?

Wrap the call in try/catch or .catch() and handle the rejection gracefully

panic during siyuan.client.fetch

Error message

panic during siyuan.client.fetch: %v

What it means

The actual HTTP request of siyuan.client.fetch runs on a background goroutine; any panic there (or a returned error) is converted into a rejection of the fetch promise with this message. It wraps unexpected kernel-side failures during request execution or response handling so plugin code sees a catchable error instead of crashing the runtime.

Solutions

Wrap the call in try/catch or .catch() and handle the rejection gracefully
Retry the request once after a short delay if the kernel was busy or restarting
Check the kernel log for the underlying panic/error detail
Verify the target API path exists and the payload size is reasonable

Example fix

// before
const res = await siyuan.client.fetch("/api/query/sql", { method: "POST", body: JSON.stringify({ stmt }) });

// after
let res;
try {
  res = await siyuan.client.fetch("/api/query/sql", { method: "POST", body: JSON.stringify({ stmt }) });
} catch (e) {
  console.error("siyuan.client.fetch failed:", e);
  res = null;
}

Defensive patterns

Strategy: try-catch

Validate before calling

async function safeKernelFetch(path, opts, retries = 1) {
  for (let i = 0; i <= retries; i++) {
    try { return await siyuan.client.fetch(path, opts); }
    catch (e) { if (i === retries) throw e; await new Promise(r => setTimeout(r, 500)); }
  }
}

Try / catch

try {
  const res = await siyuan.client.fetch(path, opts);
} catch (e) {
  // every siyuan.client.fetch failure surfaces here; log and degrade gracefully
  console.error("kernel fetch failed:", e);
}

Prevention

Always await inside try/catch — every fetch failure rejects the promise
Add one retry with backoff for transient kernel load
Keep request payloads small; check kernel logs for the underlying cause

When it happens

Trigger: A kernel-side panic while performing the HTTP request (e.g. transport failure handling, response body processing bug) or an error returned by the request path; the promise rejects with this wrapped message.

Common situations: Kernel unreachable or shutting down while a plugin request is in flight; very large or malformed responses triggering a processing bug; concurrent plugin requests during workspace close.

Understand the failure class

Background: 'Something went wrong' / 'Request failed (500)' / 'HTTP error! status: 404' — what failed HTTP requests actually mean and how to find the real cause — this error's family across 28 libraries.

Related errors

AI-assisted analysis of siyuan-note/siyuan@9f775e8a12 (2026-09-19). Data as JSON: /api/errors/70efe2d878e8fc41. Report an issue: GitHub.

Appendix: source

Thrown at kernel/plugin/api_client.go:106

								}
							}
						}
					}
				}
			}
		}

		runErr := p.worker.Run(func(rt *goja.Runtime) (_ any, err error) {
			if argErr != nil {
				err = argErr
				return
			}

			go func() {
				var err error
				defer func() {
					if r := recover(); r != nil {
						err = fmt.Errorf("panic during siyuan.client.fetch: %v", r)
					}

					if err != nil {
						p.worker.Run(func(rt *goja.Runtime) (_ any, _ error) {
							if rejectErr := reject(rt.NewGoError(err)); rejectErr != nil {
								logging.LogErrorf("[plugin:%s] siyuan.client.fetch reject: %v", p.Name, rejectErr)
							}
							return
						}, nil)
					}
				}()

				targetURL := fmt.Sprintf("http://127.0.0.1:%s%s", util.ServerPort, path)
				r := httpClient.R()
				for k, v := range headers {
					r.SetHeader(k, v)
				}
				r.SetHeader(model.XAuthTokenKey, p.token)

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