[PHP web] Export setErrNo() to make less work as pager (#2554)

## Motivation for the change, related issues

Some WP-CLI commands fail in Playground web, notably just `wp` that
normally prints the help message. This PR addresses those shortcomings.

## Implementation details

* Ensure the `setErrNo` function is always exported, otherwise some
subprocess handler code paths try to call an undefined function.
* Don't call `_free()` that may be unavailable. Call `PHPLoader["free"]`
instead.
* Wait for the `stdin` data to finish subprocess handler before exiting
our mock `less` implementation

## Testing Instructions (or ideally a Blueprint)

Confirm the E2E test included with this PR passes in the CI.

Author: adamziel

packages/php-wasm/compile/php/Dockerfile

@@ -2106,10 +2106,10 @@ RUN set -euxo pipefail; \
 	source /root/emsdk/emsdk_env.sh; \
 	if [ "$WITH_JSPI" = "yes" ]; then \
 		# Both imports and exports are required for inter-module communication with wrapped methods, e.g., wasm_recv.
-		export ASYNCIFY_FLAGS=" -s ASYNCIFY=2 -sSUPPORT_LONGJMP=wasm -fwasm-exceptions -sJSPI_IMPORTS=js_open_process,js_fd_read,js_waitpid,js_process_status,js_create_input_device,wasm_setsockopt,wasm_shutdown,wasm_close,wasm_recv,__syscall_fcntl64,js_flock,js_release_file_locks,js_waitpid,fd_close -sJSPI_EXPORTS=php_wasm_init,fd_close,wasm_sleep,wasm_read,emscripten_sleep,wasm_sapi_handle_request,wasm_sapi_request_shutdown,wasm_poll_socket,wrap_select,__wrap_select,select,php_pollfd_for,fflush,wasm_popen,wasm_read,wasm_php_exec,run_cli,wasm_recv -s EXTRA_EXPORTED_RUNTIME_METHODS=ccall,PROXYFS,wasmExports,_malloc "; \
+		export ASYNCIFY_FLAGS=" -s ASYNCIFY=2 -sSUPPORT_LONGJMP=wasm -fwasm-exceptions -sJSPI_IMPORTS=js_open_process,js_fd_read,js_waitpid,js_process_status,js_create_input_device,wasm_setsockopt,wasm_shutdown,wasm_close,wasm_recv,__syscall_fcntl64,js_flock,js_release_file_locks,js_waitpid,fd_close -sJSPI_EXPORTS=php_wasm_init,fd_close,wasm_sleep,wasm_read,emscripten_sleep,wasm_sapi_handle_request,wasm_sapi_request_shutdown,wasm_poll_socket,wrap_select,__wrap_select,select,php_pollfd_for,fflush,wasm_popen,wasm_read,wasm_php_exec,run_cli,wasm_recv -s EXTRA_EXPORTED_RUNTIME_METHODS=ccall,PROXYFS,wasmExports,_malloc,setErrNo "; \
 		echo '#define PLAYGROUND_JSPI 1' > /root/php_wasm_asyncify.h; \
 	else \
-		export ASYNCIFY_FLAGS=" -s ASYNCIFY=1 -s ASYNCIFY_IGNORE_INDIRECT=1 -s EXPORTED_RUNTIME_METHODS=ccall,PROXYFS,wasmExports $(cat /root/.emcc-php-asyncify-flags)  "; \
+		export ASYNCIFY_FLAGS=" -s ASYNCIFY=1 -s ASYNCIFY_IGNORE_INDIRECT=1 -s EXPORTED_RUNTIME_METHODS=ccall,PROXYFS,wasmExports,setErrNo $(cat /root/.emcc-php-asyncify-flags)  "; \
 		echo '' > /root/php_wasm_asyncify.h; \
 	fi; \
 	export EXPORTED_FUNCTIONS=$'["_exit", \n\

packages/php-wasm/compile/php/phpwasm-emscripten-library.js

@@ -711,9 +711,9 @@ const LibraryExample = {
 					if (!cp.stdin.closed) {
 						cp.stdin.end();
 					}
-					_free(buffer);
-					_free(iov);
-					_free(pnum);
+					PHPLoader["free"](buffer);
+					PHPLoader["free"](iov);
+					PHPLoader["free"](pnum);
 				}
 
 				// pump() can never alter the result of this function.

packages/php-wasm/supported-php-versions.mjs

@@ -6,7 +6,7 @@
  * @property {string} lastRelease
  */
 
-export const lastRefreshed = '2025-08-04T12:45:56.385Z';
+export const lastRefreshed = '2025-08-25T10:10:32.564Z';
 
 /**
  * @type {PhpVersion[]}

packages/php-wasm/universal/src/lib/sandboxed-spawn-handler-factory.ts

@@ -47,7 +47,14 @@ export function sandboxedSpawnHandlerFactory(
 			processApi.on('stdin', (data: Uint8Array) => {
 				processApi.stdout(data);
 			});
+			// Exit after the stdin stream is exhausted.
+			await new Promise((resolve) => {
+				processApi.childProcess.stdin.on('finish', () => {
+					resolve(true);
+				});
+			});
 			processApi.exit(0);
+			return;
 		} else if (binaryName === 'php') {
 			const { php, reap } = await processManager.acquirePHPInstance({
 				considerPrimary: false,

packages/php-wasm/util/src/lib/create-spawn-handler.ts

@@ -96,7 +96,7 @@ export class ProcessApi extends EventEmitterPolyfill {
 	 * first listener was registered.
 	 */
 	private stdinBuffer: Uint8Array[] | null = [];
-	private childProcess: ChildProcess;
+	public childProcess: ChildProcess;
 	constructor(childProcess: ChildProcess) {
 		super();
 		this.childProcess = childProcess;