Wait for cmd detection if running command at start up

Fixes microsoft#205744

Author: Tyriar

src/vs/workbench/contrib/terminal/browser/terminalInstance.ts

@@ -824,10 +824,29 @@ export class TerminalInstance extends Disposable implements ITerminalInstance {
 	}
 
 	async runCommand(commandLine: string, shouldExecute: boolean): Promise<void> {
+		let commandDetection = this.capabilities.get(TerminalCapability.CommandDetection);
+
+		// Await command detection if the terminal is starting up
+		if (!commandDetection && (this._processManager.processState === ProcessState.Uninitialized || this._processManager.processState === ProcessState.Launching)) {
+			const store = new DisposableStore();
+			await Promise.race([
+				new Promise<void>(r => {
+					store.add(this.capabilities.onDidAddCapabilityType(e => {
+						if (e === TerminalCapability.CommandDetection) {
+							commandDetection = this.capabilities.get(TerminalCapability.CommandDetection);
+							r();
+						}
+					}));
+				}),
+				timeout(2000),
+			]);
+			store.dispose();
+		}
+
 		// Determine whether to send ETX (ctrl+c) before running the command. This should always
 		// happen unless command detection can reliably say that a command is being entered and
 		// there is no content in the prompt
-		if (this.capabilities.get(TerminalCapability.CommandDetection)?.hasInput !== false) {
+		if (commandDetection?.hasInput !== false) {
 			await this.sendText('\x03', false);
 			// Wait a little before running the command to avoid the sequences being echoed while the ^C
 			// is being evaluated