Strict null check mainThreadComments

src/tsconfig.strictNullChecks.json

@@ -360,6 +360,7 @@
 		"./vs/workbench/test/common/memento.test.ts",
 		"./vs/workbench/test/common/notifications.test.ts",
 		"./vs/workbench/test/electron-browser/api/extHost.api.impl.test.ts",
+		"./vs/workbench/test/electron-browser/api/extHostApiCommands.test.ts",
 		"./vs/workbench/test/electron-browser/api/extHostCommands.test.ts",
 		"./vs/workbench/test/electron-browser/api/extHostConfiguration.test.ts",
 		"./vs/workbench/test/electron-browser/api/extHostDiagnostics.test.ts",
@@ -388,6 +389,8 @@
 		"./vs/workbench/test/electron-browser/api/mock.ts",
 		"./vs/workbench/test/electron-browser/api/testRPCProtocol.ts",
 		"./vs/workbench/test/electron-browser/colorRegistry.releaseTest.ts",
+		"./vs/workbench/test/electron-browser/quickopen.perf.integrationTest.ts",
+		"./vs/workbench/test/electron-browser/textsearch.perf.integrationTest.ts",
 		"./vs/workbench/test/workbenchTestServices.ts"
 	],
 	"exclude": [

src/vs/workbench/api/electron-browser/mainThreadComments.ts

@@ -142,11 +142,11 @@ export class MainThreadCommentThread implements modes.CommentThread2 {
 		return this._additionalCommands;
 	}
 
-	set deleteCommand(newCommand: modes.Command) {
+	set deleteCommand(newCommand: modes.Command | undefined) {
 		this._deleteCommand = newCommand;
 	}
 
-	get deleteCommand(): modes.Command {
+	get deleteCommand(): modes.Command | undefined {
 		return this._deleteCommand;
 	}
 
@@ -476,6 +476,9 @@ export class MainThreadComments extends Disposable implements MainThreadComments
 
 	$unregisterCommentController(handle: number): void {
 		const providerId = this._handlers.get(handle);
+		if (typeof providerId !== 'string') {
+			throw new Error('unknown handler');
+		}
 		this._commentService.unregisterCommentController(providerId);
 		this._handlers.delete(handle);
 		this._commentControllers.delete(handle);