[plugin] fix resolution of missing and promisified activation

Before a promise will be returned instead of an API or a VS Code extension is never considered activated (for missing activate fn)

Signed-off-by: Anton Kosyakov <anton.kosyakov@typefox.io>

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

@@ -35,6 +35,7 @@ import { Memento, KeyValueStorageProxy } from './plugin-storage';
 import { ExtPluginApi } from '../common/plugin-ext-api-contribution';
 import { RPCProtocol } from '../common/rpc-protocol';
 import { Emitter } from '@theia/core/lib/common/event';
+import { MaybePromise } from '@theia/core/lib/common/types';
 
 export interface PluginHost {
 
@@ -254,17 +255,18 @@ export class PluginManagerExtImpl implements PluginManagerExt, PluginManager {
         if (typeof pluginMain[plugin.lifecycle.stopMethod] === 'function') {
             stopFn = pluginMain[plugin.lifecycle.stopMethod];
         }
+        // No activate found => the module is the extension's exports
+        let pluginExports = pluginMain;
         if (typeof pluginMain[plugin.lifecycle.startMethod] === 'function') {
-            const pluginExport = await pluginMain[plugin.lifecycle.startMethod].apply(getGlobal(), [pluginContext]);
-            this.activatedPlugins.set(plugin.model.id, new ActivatedPlugin(pluginContext, pluginExport, stopFn));
+            const maybePluginExports: MaybePromise<PluginAPI> | undefined = await pluginMain[plugin.lifecycle.startMethod].apply(getGlobal(), [pluginContext]);
+            pluginExports = await maybePluginExports;
+        }
+        this.activatedPlugins.set(plugin.model.id, new ActivatedPlugin(pluginContext, pluginExports, stopFn));
 
-            // resolve activation promise
-            if (this.pluginActivationPromises.has(plugin.model.id)) {
-                this.pluginActivationPromises.get(plugin.model.id)!.resolve();
-                this.pluginActivationPromises.delete(plugin.model.id);
-            }
-        } else {
-            console.log(`There is no ${plugin.lifecycle.startMethod} method on plugin`);
+        // resolve activation promise
+        if (this.pluginActivationPromises.has(plugin.model.id)) {
+            this.pluginActivationPromises.get(plugin.model.id)!.resolve();
+            this.pluginActivationPromises.delete(plugin.model.id);
         }
     }