Studio: Finish site creation when the CLI reports done, not when telemetry lets the process exit

apps/cli/index.ts

@@ -331,6 +331,12 @@ async function main() {
 		.strict();
 
 	await studioArgv.argv;
+
+	// Tell the host that started this command it has finished, so it needn't wait for the
+	// process to exit after best-effort telemetry requests complete.
+	if ( process.connected && ! process.exitCode ) {
+		process.send?.( { action: 'done' } );
+	}
 }
 
 void main();

packages/common/lib/cli-process.ts

@@ -84,6 +84,16 @@ const cliErrorMessageSchema = z.object( {
 	message: z.string(),
 } );
 
+/**
+ * Sent by the CLI once a command has finished successfully. Its process can stay alive a while
+ * longer to finish sending best-effort telemetry, which its host doesn't need to wait for.
+ */
+const cliDoneMessageSchema = z.object( { action: z.literal( 'done' ) } );
+
+export function isCliCommandDone( message: unknown ): boolean {
+	return cliDoneMessageSchema.safeParse( message ).success;
+}
+
 type CliCommandEventEmitter< CapturesOutput extends boolean > = TypedEventEmitter<
 	CliCommandEventMap< CapturesOutput >
 >;
@@ -327,7 +337,8 @@ const cliProgressMessageSchema = z.object( {
 
 /**
  * Runs a CLI command and resolves with the result it reports (`logger.reportResult`), parsed by
- * `schema`. Rejects with the command's error, or when it succeeds without reporting a result.
+ * `schema`, once the command has finished. Rejects with the command's error, or when it succeeds
+ * without reporting a result.
  */
 export function runCliCommand< T >(
 	execute: ExecuteCliCommand,
@@ -338,27 +349,32 @@ export function runCliCommand< T >(
 	return new Promise( ( resolve, reject ) => {
 		let result: z.ZodSafeParseResult< T > | undefined;
 		const [ emitter ] = execute( args, { output: 'capture', logPrefix: options.logPrefix } );
+		const settle = () => {
+			if ( result?.success ) {
+				resolve( result.data );
+			} else {
+				reject(
+					result?.error ??
+						new Error( `\`studio ${ args.slice( 0, 2 ).join( ' ' ) }\` reported no result.` )
+				);
+			}
+		};
 		emitter.on( 'data', ( { data } ) => {
 			const message = cliResultMessageSchema.safeParse( data );
 			if ( message.success ) {
 				result = schema.safeParse( message.data.value );
 				return;
 			}
+			if ( isCliCommandDone( data ) ) {
+				settle();
+				return;
+			}
 			const progress = cliProgressMessageSchema.safeParse( data );
 			if ( progress.success ) {
 				options.onProgress?.( progress.data.message );
 			}
 		} );
-		emitter.on( 'success', () => {
-			if ( result?.success ) {
-				resolve( result.data );
-			} else {
-				reject(
-					result?.error ??
-						new Error( `\`studio ${ args.slice( 0, 2 ).join( ' ' ) }\` reported no result.` )
-				);
-			}
-		} );
+		emitter.on( 'success', settle );
 		emitter.on( 'failure', ( { error } ) => reject( error ) );
 		emitter.on( 'error', ( { error } ) => reject( error ) );
 	} );

packages/common/lib/tests/cli-process.test.ts

@@ -115,6 +115,21 @@ describe( 'runCliCommand', () => {
 		);
 	} );
 
+	it( 'resolves once the command says it finished, while its process is still running', async () => {
+		const emitter = new EventEmitter();
+		const execute = vi.fn( () => {
+			queueMicrotask( () => {
+				emitter.emit( 'data', { data: { action: 'result', value: { url: 'https://a.example' } } } );
+				emitter.emit( 'data', { data: { action: 'done' } } );
+			} );
+			return [ emitter, {} ];
+		} ) as unknown as ExecuteCliCommand;
+
+		await expect( runCliCommand( execute, [ 'site', 'create' ], schema ) ).resolves.toEqual( {
+			url: 'https://a.example',
+		} );
+	} );
+
 	it( 'rejects with the command error when it fails', async () => {
 		const emitter = new EventEmitter();
 		const execute = vi.fn( () => {

packages/common/sites/snapshots.ts

@@ -1,6 +1,10 @@
 import crypto from 'node:crypto';
 import { z } from 'zod';
-import { runCliCommand, type ExecuteCliCommand } from '@studio/common/lib/cli-process';
+import {
+	isCliCommandDone,
+	runCliCommand,
+	type ExecuteCliCommand,
+} from '@studio/common/lib/cli-process';
 import { PreviewCommandLoggerAction } from '@studio/common/logger-actions';
 import { snapshotSchema, type Snapshot } from '@studio/common/types/snapshot';
 
@@ -60,6 +64,9 @@ export function createSnapshotManager( ctx: SnapshotCommandContext ): SnapshotMa
 		const [ emitter ] = ctx.executeCliCommand( args, { output: 'capture', logPrefix: 'preview' } );
 
 		emitter.on( 'data', ( { data } ) => {
+			if ( isCliCommandDone( data ) ) {
+				return;
+			}
 			const parsed = snapshotEventSchema.safeParse( data );
 			if ( ! parsed.success ) {
 				console.error( 'Invalid snapshot event:', parsed.error );