[Bug]: iOS with golang static lib webview load failure

[betamos]

Capacitor Version

💊 Capacitor Doctor 💊

Latest Dependencies:

@capacitor/cli: 7.0.1
@capacitor/core: 7.0.1
@capacitor/android: 7.0.1
@capacitor/ios: 7.0.1

Installed Dependencies:

@capacitor/android: not installed
@capacitor/cli: 7.0.1
@capacitor/core: 7.0.1
@capacitor/ios: 7.0.1

[success] iOS looking great! 👌

Other API Details

➜  mobile git:(cap) ✗ npm --version 
11.0.0
➜  mobile git:(cap) ✗ node --version
v23.6.0
➜  mobile git:(cap) ✗ pod --version
1.16.2
➜  mobile git:(cap) ✗ go version
go version go1.23.4 darwin/arm64

Platforms Affected

• iOS
• Android
• Web

Current Behavior

I have custom native code to add a gomobile static lib as a framework. When I switched to use my bundled site in public for prod, it failed with:

⚡️  WebView failed provisional navigation
⚡️  Error: The file “public” couldn’t be opened.

This happens in both simulator and physical iPhone (both iOS 18.2).

This error returns exactly one search result: #6974 . It's closed, but nevertheless:

• It's suggested there's a workaround, but not how? I share mine below.
• The Go team blames Apple (Foundation Framework) and proceeds to stick head into sand
• Tim Apple isn't even informed, afaik
• In development with HMR, I didn't notice this because if there's a serverUrl it's not triggered

The gomobile command used was: gomobile bind -ldflags="-s" -target ios -tags ios -o ./ios/App/Pld.xcframework

Expected Behavior

Webview should load normally & peacefully.

Project Reproduction

it's not easy to do atm...

Additional Information

I managed to find a workaround through MyViewController (see docs for how to set it up). The actual fix is a one-liner, but to set it up is quite tedious, especially if you're not already using a custom view controller.

import UIKit
import Capacitor

public struct CustomRouter: Router {
    public init() {}
    public var basePath: String = ""
    public func route(for path: String) -> String {
        // FIX: Never pass an empty string here
        let pathUrl = URL(fileURLWithPath: path.isEmpty ? "/" : path)

        // If there's no path extension it also means the path is empty or a SPA route
        if pathUrl.pathExtension.isEmpty {
            return basePath + "/index.html"
        }

        return basePath + path
    }
}

class MyViewController: CAPBridgeViewController {
    
    // CRITICAL: Must pass our own router otherwise *no bueno* 
    override open func router() -> any Router {
        CustomRouter()
    }
    override open func capacitorDidLoad() {
        // Here I register my plugin, but the failure occurs even if I don't register it.
        bridge?.registerPluginInstance(PldPlugin())
    }
}

My understanding is that the non-deterministic behavior of URL(fileURLWithPath:) occurs when the path is empty. Normally an empty path translates to file:/// which is equivalent to passing /.

God knows what combination of things causes this to happen, but if Capacitor can avoid this non-determinism perhaps that's an improvement? It certainly is for me (and clearly, whoever posted that other issue). Happy to send a PR if so.

(Obligatory thanks for a great framework. I'm new to mobile dev and I can't thank the contributors enough.)

[ionitron-bot]

This issue needs more information before it can be addressed. In particular, the reporter needs to provide a minimal sample app that demonstrates the issue. If no sample app is provided within 15 days, the issue will be closed.
Please see the Contributing Guide for how to create a Sample App.
Thanks! Ionitron 💙