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

Check the kernel log for the panic stack (the message includes the recovered value) and report it with the plugin name.

panic during siyuan.client.fetch: %v

Error message

panic during siyuan.client.fetch: %v

What it means

A panic was recovered inside the background goroutine that performs the HTTP request for siyuan.client.fetch. The %v is the recovered panic value. This is an internal failure (nil pointer, slice out of range, etc.) in the request path, not a caller argument error — argument errors are caught earlier and reject with their own message.

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)

View on GitHub (pinned to 251596fc0d)

Solutions

Check the kernel log for the panic stack (the message includes the recovered value) and report it with the plugin name.
Ensure the plugin is not being unloaded/reloaded while requests are in flight.
Update to the latest kernel/plugin version — panics are usually fixed bugs.

Example fix

try {
  await siyuan.client.fetch('/api/x');
} catch (e) {
  // internal panic, not an argument error — log and degrade
  console.error('fetch panic', e);
}

Defensive patterns

Strategy: try-catch

Try / catch

try {
  const res = await siyuan.client.fetch('/api/x');
} catch (e) {
  if (String(e).startsWith('panic during')) {
    // internal runtime failure — log; optionally retry once
  } else {
    // argument or network error — handle by message
  }
}

Prevention

Always await fetch inside try/catch in plugins.
Avoid unloading/reloading a plugin while it has pending requests.
Keep kernel and plugin runtime versions in sync.

When it happens

Trigger: A bug in the kernel plugin runtime or a dependency panicking during request construction, send, or response assembly; or the plugin being unloaded (context cancelled) mid-request racing with response building.

Common situations: Kernel/plugin version mismatch, plugin hot-reload while a fetch is in flight, or an unhandled nil from httpClient.R(). Rare in normal use.

Related errors

AI-assisted analysis of siyuan-note/siyuan@251596fc0d (2026-08-12). Data as JSON: /api/errors/70efe2d878e8fc41. Report an issue: GitHub.