Fix GH-24256: fclose() returns false for wrappers without stream_flush()

NEWS

@@ -40,6 +40,8 @@ PHP                                                                        NEWS
     when getpwnam_r() needs a larger buffer. (Ilia Alshanetsky)
   . Fixed password_get_info() and password_needs_rehash() accepting malformed
     bcrypt costs. (Ilia Alshanetsky)
+  . Fixed bug GH-24256 (fclose() returns false for stream wrappers without
+    stream_flush()). (Lazizbek Ergashev)
 
 - Zip:
   . Fixed use-after-free when re-entering ZipArchive during destruction or

ext/standard/tests/file/gh24256.phpt

@@ -0,0 +1,34 @@
+--TEST--
+GH-24256 (fclose() returns false for stream wrappers without stream_flush())
+--FILE--
+<?php
+class TestStream {
+    public $context;
+
+    function stream_open($path, $mode, $options, &$opened_path) {
+        return true;
+    }
+
+    function stream_write($data) {
+        return strlen($data);
+    }
+
+    function url_stat($path, $flags) {
+        return false;
+    }
+}
+
+stream_wrapper_register('test', TestStream::class);
+
+$fp = fopen('test://foo', 'w');
+var_dump(fwrite($fp, 'data'));
+var_dump(fclose($fp));
+
+var_dump(file_put_contents('test://foo', 'data'));
+var_dump(copy(__FILE__, 'test://foo'));
+?>
+--EXPECT--
+int(4)
+bool(true)
+int(4)
+bool(true)

main/streams/userspace.c

@@ -741,7 +741,13 @@ static int php_userstreamop_flush(php_stream *stream)
 	zend_result call_result = zend_call_method_if_exists(Z_OBJ(us->object), func_name, &retval, 0, NULL);
 	zend_string_release_ex(func_name, false);
 
-	int ret = call_result == SUCCESS && Z_TYPE(retval) != IS_UNDEF && zend_is_true(&retval) ? 0 : -1;
+	int ret;
+	if (call_result == FAILURE) {
+		/* stream_flush is optional, so a missing one is not an error when closing */
+		ret = stream->in_free ? 0 : -1;
+	} else {
+		ret = Z_TYPE(retval) != IS_UNDEF && zend_is_true(&retval) ? 0 : -1;
+	}
 
 	zval_ptr_dtor(&retval);