dev server logs "Unknown message from front end: runtime:ready" for every browser client

[Trainingdlu]

Wails version family

v2

Operating System

Windows

Description

Every time a browser client loads the page under wails dev, two error lines show up in the terminal:

ERR | process message error: runtime:ready -> Unknown message from front end: runtime:ready
ERR | Unknown message from front end: runtime:ready

Nothing actually breaks, but the wording cost me a while: "Unknown message from front end" sounds like my own frontend sent something malformed. It didn't. runtime:ready comes from the runtime Wails injects.

The desktop window doesn't trigger it. Only browser clients do.

To Reproduce

1. wails init -n testbed -t vanilla
2. cd testbed && wails dev
3. Wait for the navigate to: http://localhost:34115 line. Terminal is still clean at this point.
4. Open http://localhost:34115 in a browser.
5. Two ERR lines appear, and two more on every refresh.

Expected behaviour

The dev server should swallow runtime:ready the way the desktop frontends already do, and log nothing. It's a runtime control message, not application traffic.

Screenshots

No response

Attempted Fixes

Traced it through the code:

• The injected runtime always ends init with WailsInvoke("runtime:ready") (v2/internal/frontend/runtime/desktop/main.js).
• In dev mode the asset server picks the IPC shim by User-Agent (v2/pkg/assetserver/assetserver_dev.go), so the desktop webview and a browser end up on different transports.
• windows/darwin/linux all consume runtime:ready before dispatching. The dev server's websocket loop only special-cases drag, so it reaches dispatcher.ProcessMessage, which routes on the first byte and has no case for r.

Two lines rather than one because the dispatcher logs it in a deferred handler and the dev server then logs the returned error again.

Searched the tracker for "Unknown message from front end" and "process message error", nothing existing. (runtime:ready itself isn't searchable, GitHub splits on the colon.)

I have a fix, PR to follow.

System Details

# Wails
Version | v2.12.0

# System
| OS           | Windows 10 Home China                                              |
| Version      | 2009 (Build: 26200)                                                |
| ID           | 25H2                                                               |
| Go Version   | go1.26.4                                                           |
| Platform     | windows                                                            |
| Architecture | amd64                                                              |
| CPU          | Intel(R) Core(TM) i7-14700HX                                       |
| GPU 1        | NVIDIA GeForce RTX 4070 Laptop GPU (NVIDIA) - Driver: 32.0.15.8088 |
| GPU 2        | Intel(R) UHD Graphics (Intel Corporation) - Driver: 32.0.101.6790  |
| Memory       | 16GB                                                               |

# Dependencies
| Dependency | Package Name | Status    | Version       |
| WebView2   | N/A          | Installed | 150.0.4078.83 |
| Nodejs     | N/A          | Installed | 22.15.1       |
| npm        | N/A          | Installed | 10.9.2        |
| *upx       | N/A          | Available |               |
| *nsis      | N/A          | Available |               |

Additional context

Only affects wails dev with a browser client, since the message only reaches the dispatcher over the websocket transport.

Terminal output from the steps above, trimmed to the first two loads:

Using DevServer URL: http://localhost:34115
Using Frontend DevServer URL: http://localhost:5173/
INF | Serving assets from frontend DevServer URL: http://localhost:5173/
Watching (sub)/directory: C:\Users...\testbed
[WebView2] Environment created successfully

To develop in the browser and call your bound Go methods from Javascript, navigate to: http://localhost:34115
ERR | process message error: runtime:ready -> Unknown message from front end: runtime:ready
ERR | Unknown message from front end: runtime:ready
ERR | process message error: runtime:ready -> Unknown message from front end: runtime:ready
ERR | Unknown message from front end: runtime:ready

The desktop window had already loaded before navigate to printed, and logged nothing of its own. Everything above appeared only once the browser connected.