Web extensions no longer load

[sdirix]

Bug Description:

VS Code web extensions fail to load.

root ERROR Failed to start plugins for 'frontend' host
Error: Failed to execute 'importScripts' on 'WorkerGlobalScope': The script at 'http://localhost:3000/context/plugin-vscode-init-fe.js' failed to load.
    at initialize (http://localhost:3000/packages_plugin-ext_lib_hosted_browser_worker_worker-main_js.js:9770:13)
    at http://localhost:3000/packages_plugin-ext_lib_hosted_browser_worker_worker-main_js.js:9819:21
    at Array.map (<anonymous>)
    at Object.init (http://localhost:3000/packages_plugin-ext_lib_hosted_browser_worker_worker-main_js.js:9813:57)
    at PluginManagerExtImpl.$start (http://localhost:3000/packages_plugin-ext_lib_hosted_browser_worker_worker-main_js.js:19499:59)
    at http://localhost:3000/packages_plugin-ext_lib_common_plugin-api-rpc_js.js:994:71
    at async RpcProtocol.handleRequest (http://localhost:3000/packages_plugin-ext_lib_hosted_browser_worker_worker-main_js.js:3852:28)

The code mentioning plugin-vscode-init-fe.js can be found here.
Executing a manual GET on http://localhost:3000/context/plugin-vscode-init-fe.js also fails.

The error is very likely related to the backend bundling. When deleting examples/browser/lib/backend directory and thereby forcing the non-bundling code path, the http://localhost:3000/context/plugin-vscode-init-fe.j is available again and the VS Code web extension loads.

The file is served here which fails in the bundling case.

Steps to Reproduce:

1. Add a VS Code web extension to the plugins directory (for example generated via yo code --extensionType web)
2. Build and start Theia browser example
3. Check error in the logs

Additional Information

• Operating System: Linux
• Theia Version: 6607185

[sdirix]

Thank you @msujew for the quick fix!