Acknowledge that telemetryListener may be undefined

extensions/ql-vscode/src/commandRunner.ts

@@ -147,7 +147,7 @@ export function commandRunner(
       return undefined;
     } finally {
       const executionTime = Date.now() - startTime;
-      telemetryListener.sendCommandUsage(commandId, executionTime, error);
+      telemetryListener?.sendCommandUsage(commandId, executionTime, error);
     }
   });
 }
@@ -201,7 +201,7 @@ export function commandRunnerWithProgress<R>(
       return undefined;
     } finally {
       const executionTime = Date.now() - startTime;
-      telemetryListener.sendCommandUsage(commandId, executionTime, error);
+      telemetryListener?.sendCommandUsage(commandId, executionTime, error);
     }
   });
 }

extensions/ql-vscode/src/telemetry.ts

@@ -227,12 +227,15 @@ export class TelemetryListener extends ConfigListener {
 /**
  * The global Telemetry instance
  */
-export let telemetryListener: TelemetryListener;
+export let telemetryListener: TelemetryListener | undefined;
 
 export async function initializeTelemetry(
   extension: Extension<any>,
   ctx: ExtensionContext,
 ): Promise<void> {
+  if (telemetryListener !== undefined) {
+    throw new Error("Telemetry is already initialized");
+  }
   telemetryListener = new TelemetryListener(
     extension.id,
     extension.packageJSON.version,