Improve handling of empty #[\Deprecated] message

Author: TimWolla

Zend/tests/attributes/deprecated/008.phpt

@@ -0,0 +1,14 @@
+--TEST--
+#[\Deprecated]: Empty message
+--FILE--
+<?php
+
+#[\Deprecated("")]
+function test() {
+}
+
+test();
+
+?>
+--EXPECTF--
+Deprecated: Function test() is deprecated in %s on line %d

Zend/zend_execute.c

@@ -1726,7 +1726,7 @@ ZEND_API ZEND_COLD void zend_wrong_string_offset_error(void)
 ZEND_API ZEND_COLD void ZEND_FASTCALL zend_deprecated_function(const zend_function *fbc)
 {
 	zend_attribute *deprecated;
-	zend_string *message_suffix = NULL;
+	zend_string *message_suffix = zend_empty_string;
 
 	if (fbc->common.attributes != NULL) {
 		deprecated = zend_get_attribute_str(fbc->common.attributes, "deprecated", sizeof("deprecated")-1);
@@ -1742,7 +1742,7 @@ ZEND_API ZEND_COLD void ZEND_FASTCALL zend_deprecated_function(const zend_functi
 
 	int code = fbc->type == ZEND_INTERNAL_FUNCTION ? E_DEPRECATED : E_USER_DEPRECATED;
 
-	if (message_suffix != NULL) {
+	if (ZSTR_LEN(message_suffix) > 0) {
 		if (fbc->common.scope) {
 			zend_error_unchecked(code, "Method %s::%s() is deprecated, %S",
 				ZSTR_VAL(fbc->common.scope->name),