Replace no-op spawn handler with native child_process.spawn bridge

The createNoopSpawnHandler unconditionally replaced PHP process spawning
with a handler that immediately exits with code 1, silently breaking
proc_open, exec, shell_exec, popen, and system calls.

This replaces it with a handler that bridges to Node.js child_process.spawn,
which php-wasm's setSpawnHandler already supports directly. Studio is a local
development tool where PHP already has host filesystem access via
createNodeFsMountHandler mounts, so process spawning is consistent with the
existing trust model.

Fixes: #3044
See also: #2519

Author: chubes4

apps/cli/lib/run-wp-cli-command.ts

@@ -1,3 +1,4 @@
+import { spawn } from 'node:child_process';
 import { rootCertificates } from 'node:tls';
 import { loadNodeRuntime, createNodeFsMountHandler } from '@php-wasm/node';
 import {
@@ -6,8 +7,8 @@ import {
 	PHP,
 	setPhpIniEntries,
 	ProcessIdAllocator,
+	type SpawnHandler,
 } from '@php-wasm/universal';
-import { createSpawnHandler } from '@php-wasm/util';
 import { IS_JSPI_AVAILABLE } from '@studio/common/lib/jspi';
 import { cleanupLegacyMuPlugins, getMuPlugins } from '@studio/common/lib/mu-plugins';
 import { LatestSupportedPHPVersion } from '@studio/common/types/php-versions';
@@ -18,22 +19,8 @@ import { getSqliteCommandPath, getWpCliPharPath } from 'cli/lib/server-files';
 const processIdAllocator = new ProcessIdAllocator();
 const PLAYGROUND_INTERNAL_SHARED_FOLDER = '/internal/shared';
 
-/**
- * Creates a no-op spawn handler that immediately exits with code 1.
- * This allows process spawning functions (proc_open, exec, etc.) to be called
- * without crashing, but they will fail gracefully. WP-CLI detects these failures
- * and falls back to single-threaded mode.
- *
- * The timeout before exit is required by the createSpawnHandler API — PHP needs
- * an event loop tick to set up its stream listeners after proc_open() returns.
- * Without it, the process exits before PHP registers its handlers and
- * createSpawnHandler throws a "exited synchronously" error.
- */
-function createNoopSpawnHandler() {
-	return createSpawnHandler( async ( args, processApi ) => {
-		await new Promise( ( resolve ) => setTimeout( resolve, 1 ) );
-		processApi.exit( 1 );
-	} );
+function createNativeSpawnHandler(): SpawnHandler {
+	return spawn as unknown as SpawnHandler;
 }
 
 export interface RunWpCliCommandOptions {
@@ -77,7 +64,7 @@ export async function runWpCliCommand(
 			allow_url_fopen: 1,
 		} );
 
-		await php.setSpawnHandler( createNoopSpawnHandler() );
+		await php.setSpawnHandler( createNativeSpawnHandler() );
 
 		await cleanupLegacyMuPlugins( siteFolder );
 
@@ -137,7 +124,7 @@ export async function runGlobalWpCliCommand( args: string[] ): Promise< Disposab
 			allow_url_fopen: 1,
 		} );
 
-		await php.setSpawnHandler( createNoopSpawnHandler() );
+		await php.setSpawnHandler( createNativeSpawnHandler() );
 
 		await php.mount( '/tmp/wp-cli.phar', createNodeFsMountHandler( getWpCliPharPath() ) );