[plugin system] Add stubbed support for proposed extensions.allAcross ExtensionHosts and related APIs

packages/plugin-ext/src/plugin/plugin-context.ts

@@ -753,7 +753,8 @@ export function createAPIFactory(
 
         const extensions: typeof theia.extensions = Object.freeze({
             // eslint-disable-next-line @typescript-eslint/no-explicit-any
-            getExtension<T = any>(extensionId: string): theia.Extension<T> | undefined {
+            getExtension<T = any>(extensionId: string, includeFromDifferentExtensionHosts: boolean = false): theia.Extension<T> | undefined {
+                includeFromDifferentExtensionHosts = false;
                 const plg = pluginManager.getPluginById(extensionId.toLowerCase());
                 if (plg) {
                     return new PluginExt(pluginManager, plg);
@@ -764,6 +765,10 @@ export function createAPIFactory(
             get all(): readonly theia.Extension<any>[] {
                 return pluginManager.getAllPlugins().map(plg => new PluginExt(pluginManager, plg));
             },
+            get allAcrossExtensionHosts(): readonly theia.Extension<any>[] {
+                // we only support one extension host ATM so equivalent to calling "all()"
+                return this.all;
+            },
             get onDidChange(): theia.Event<void> {
                 return pluginManager.onDidChange;
             }
@@ -1369,13 +1374,15 @@ export class PluginExt<T> extends Plugin<T> implements ExtensionPlugin<T> {
     extensionPath: string;
     extensionUri: theia.Uri;
     extensionKind: ExtensionKind;
+    isFromDifferentExtensionHost: boolean;
 
-    constructor(protected override readonly pluginManager: PluginManager, plugin: InternalPlugin) {
+    constructor(protected override readonly pluginManager: PluginManager, plugin: InternalPlugin, isFromDifferentExtensionHost = false) {
         super(pluginManager, plugin);
 
         this.extensionPath = this.pluginPath;
         this.extensionUri = this.pluginUri;
         this.extensionKind = ExtensionKind.UI; // stub as a local extension (not running on a remote workspace)
+        this.isFromDifferentExtensionHost = isFromDifferentExtensionHost;
     }
 
     override get isActive(): boolean {

packages/plugin/src/theia-proposed.d.ts

@@ -608,6 +608,40 @@ export module '@theia/plugin' {
         export function registerTimelineProvider(scheme: string | string[], provider: TimelineProvider): Disposable;
     }
 
+    // Copied from https://github.com/microsoft/vscode/blob/ad4470522ecd858cfaf53a87c2702d7a40946ba1/src/vscode-dts/vscode.proposed.extensionsAny.d.ts
+    // https://github.com/microsoft/vscode/issues/145307
+
+    export interface Extension<T> {
+
+        /**
+         * `true` when the extension is associated to another extension host.
+         *
+         * *Note* that an extension from another extension host cannot export
+         * API, e.g {@link Extension.exports its exports} are always `undefined`.
+         */
+        readonly isFromDifferentExtensionHost: boolean;
+    }
+
+    export namespace extensions {
+
+        /**
+         * Get an extension by its full identifier in the form of: `publisher.name`.
+         *
+         * @param extensionId An extension identifier.
+         * @param includeDifferentExtensionHosts Include extensions from different extension host
+         * @return An extension or `undefined`.
+         */
+        export function getExtension<T = any>(extensionId: string, includeDifferentExtensionHosts: boolean): Extension<T> | undefined;
+
+        /**
+         * All extensions across all extension hosts.
+         *
+         * @see {@link Extension.isFromDifferentExtensionHost}
+         */
+        export const allAcrossExtensionHosts: readonly Extension<void>[];
+
+    }
+
     // #endregion
 }