Fix preloading of enums

We should not store constants that resolve to objects.

Author: nikic

ext/opcache/ZendAccelerator.c

@@ -3711,6 +3711,19 @@ static void get_unlinked_dependency(zend_class_entry *ce, const char **kind, con
 	}
 }
 
+static zend_result preload_update_constant(zval *val, zend_class_entry *scope)
+{
+	zval tmp;
+	ZVAL_COPY(&tmp, val);
+	if (zval_update_constant_ex(&tmp, scope) == FAILURE || Z_TYPE(tmp) == IS_OBJECT) {
+		zval_ptr_dtor(&tmp);
+		return FAILURE;
+	}
+	zval_ptr_dtor_nogc(val);
+	ZVAL_COPY_VALUE(val, &tmp);
+	return SUCCESS;
+}
+
 static bool preload_try_resolve_constants(zend_class_entry *ce)
 {
 	bool ok, changed, was_changed = 0;
@@ -3724,7 +3737,7 @@ static bool preload_try_resolve_constants(zend_class_entry *ce)
 		ZEND_HASH_FOREACH_PTR(&ce->constants_table, c) {
 			val = &c->value;
 			if (Z_TYPE_P(val) == IS_CONSTANT_AST) {
-				if (EXPECTED(zval_update_constant_ex(val, c->ce) == SUCCESS)) {
+				if (EXPECTED(preload_update_constant(val, c->ce) == SUCCESS)) {
 					was_changed = changed = 1;
 				} else {
 					ok = 0;
@@ -3742,7 +3755,7 @@ static bool preload_try_resolve_constants(zend_class_entry *ce)
 				val = &ce->default_properties_table[i];
 				if (Z_TYPE_P(val) == IS_CONSTANT_AST) {
 					zend_property_info *prop = ce->properties_info_table[i];
-					if (UNEXPECTED(zval_update_constant_ex(val, prop->ce) != SUCCESS)) {
+					if (UNEXPECTED(preload_update_constant(val, prop->ce) != SUCCESS)) {
 						resolved = ok = 0;
 					}
 				}
@@ -3758,7 +3771,7 @@ static bool preload_try_resolve_constants(zend_class_entry *ce)
 			val = ce->default_static_members_table + ce->default_static_members_count - 1;
 			while (count) {
 				if (Z_TYPE_P(val) == IS_CONSTANT_AST) {
-					if (UNEXPECTED(zval_update_constant_ex(val, ce) != SUCCESS)) {
+					if (UNEXPECTED(preload_update_constant(val, ce) != SUCCESS)) {
 						resolved = ok = 0;
 					}
 				}

ext/opcache/tests/preload_enum.inc

@@ -0,0 +1,6 @@
+<?php
+
+enum MyEnum {
+    case Foo;
+    case Bar;
+}

ext/opcache/tests/preload_enum.phpt

@@ -0,0 +1,20 @@
+--TEST--
+Enum preloading
+--EXTENSIONS--
+opcache
+--INI--
+opcache.enable=1
+opcache.enable_cli=1
+opcache.optimization_level=-1
+opcache.preload={PWD}/preload_enum.inc
+--SKIPIF--
+<?php
+if (PHP_OS_FAMILY == 'Windows') die('skip Preloading is not supported on Windows');
+--FILE--
+<?php
+
+var_dump(MyEnum::Foo);
+
+?>
+--EXPECT--
+enum(MyEnum::Foo)