viewsWelcome behavior does not match VSCode's

[clovis-dugue]

Bug Description:

ViewsWelcome content does not show on a standard VSCode extension.
It shows on the one provided in PR #8678

Steps to Reproduce:

See https://github.com/clovis-dugue/theia-viewswelcome-issue

Additional Information

• Operating System: Ubuntu LTS
• Theia Version: Current master branch browser example (1.12.0)
• Initial discussion: [vscode] support viewsWelcome contribution point #7178 (comment)

[xcariba]

I've investigated this issue a little bit. It seems that viewsWelcome will not show up until getChildren() promise is resolved. If promise returns empty array it shows up. Theia tries to load welcome widget, but it cannot find it - it cannot find it by key "{"factoryId":"plugin-view-data","options":{"id":"myExtensionId"}}". Seems that it is registered only after root model is fetched.

[clovis-dugue]

Thanks for the input! I don't really have time for this right now but I will be sure to use it when coming back to it.

[davide-sergi]

You need to register a TreeDataProvider which return an empty tree. This is not required for vscode environment.
You can keep same package.json.

I solved with following code:

import * as vscode from 'vscode';

export async function activate(context: vscode.ExtensionContext) { 
  vscode.window.registerTreeDataProvider(
	  "my-view-id",
	  new EmptyTreeDataProvider()
  );
}

export function deactivate() {}

export class EmptyTreeDataProvider implements vscode.TreeDataProvider<any> {
	constructor() {}

	getTreeItem(element: any): vscode.TreeItem {
		return {};
	}

	getChildren(element?: any): Thenable<any[]> {
		return new Promise((resolve) => resolve([]));
	}
}

[jcortell68]

@davide-sergi Your workaround worked for me. Thanks!