Bug: AbortSignal.timeout is not a function

[unicome37]

AbortSignal.timeout() is a new Web API not available in older WebView2. See details below.

[Please copy the content from ISSUE_REPORT.md file]
Bug Report: AbortSignal.timeout is not a function

Summary

OpenCode fails to start on Windows with the error:

TypeError: AbortSignal.timeout is not a function

This occurs because AbortSignal.timeout() is a relatively new Web API that is not available in older WebView2 versions.

Environment

• OS: Windows
• OpenCode Version: 1.1.13 (installed from D:\OpenCode\OpenCode.exe)
• WebView2 Version: [Check with: powershell "Get-ItemProperty 'HKLM:\SOFTWARE\WOW6432Node\Microsoft\EdgeUpdate\Clients\{F3017226-FE2A-4295-8BDF-00C3A9A7E4C5}' | Select-Object pv"]

Steps to Reproduce

1. Install OpenCode
2. Launch OpenCode.exe
3. Application fails to start with error in console

Error Details

TypeError: AbortSignal.timeout is not a function
    at check (http://tauri.localhost/assets/index-DOiGjfJu.js:1705:38678)
    at run (http://tauri.localhost/assets/index-DOiGjfJu.js:1705:38843)
    at Object.fn (http://tauri.localhost/assets/index-DOiGjfJu.js:1705:38896)
    at runComputation (http://tauri.localhost/assets/index-DOiGjfJu.js:2:8250)
    at updateComputation (http://tauri.localhost/assets/index-DOiGjfJu.js:2:7981)
    at runTop (http://tauri.localhost/assets/index-DOiGjfJu.js:2:9466)
    at runUserEffects (http://tauri.localhost/assets/index-DOiGjfJu.js:2:10730)
    at http://tauri.localhost/assets/index-DOiGjfJu.js:2:10322
    at runUpdates (http://tauri.localhost/assets/index-DOiGjfJu.js:2:9655)
    at completeUpdates (http://tauri.localhost/assets/index-DOiGjfJu.js:2:10315)

The error occurs in the updater plugin's check() function which uses AbortSignal.timeout().

Root Cause

The codebase uses AbortSignal.timeout() in multiple locations:

• packages/app/src/context/server.tsx
• packages/app/src/components/dialog-select-server.tsx
• packages/opencode/src/provider/models.ts
• packages/opencode/src/provider/provider.ts
• packages/opencode/src/session/system.ts

This API is only available in:

• Chrome 103+
• Node.js 17.3.0+, 16.14.0+
• WebView2 (older versions don't support it)

Proposed Fix

Add a polyfill for AbortSignal.timeout at the entry point of each package.

Implementation

Create a polyfill file packages/util/src/abort-signal-polyfill.ts:

/**
 * Polyfill for AbortSignal.timeout
 *
 * This API is not available in older WebView2 versions.
 * This polyfill provides a compatible implementation.
 *
 * See: https://developer.mozilla.org/en-US/docs/Web/API/AbortSignal/timeout_static
 */

if (typeof (AbortSignal as any).timeout !== 'function') {
  (AbortSignal as any).timeout = function(ms: number): AbortSignal {
    const controller = new AbortController();
    setTimeout(() => controller.abort(), ms);
    return controller.signal;
  };
}

Then import it at the top of entry points:

• packages/desktop/src/index.tsx
• packages/app/src/index.ts
• packages/opencode/src/index.ts

Workaround

Users can work around this by:

1. Upgrading WebView2 to the latest version
2. Or installing Microsoft Edge (which includes the latest WebView2)

However, a polyfill is the better solution as it ensures compatibility.

Impact

This blocks users from using OpenCode on systems with older WebView2 versions, which is still common on Windows 10/11.

Related

• MDN: https://developer.mozilla.org/en-US/docs/Web/API/AbortSignal/timeout_static
• Chrome Platform Status: https://chromestatus.com/feature/5669063187824640