Fix GH-18567: Preloading with internal class alias triggers assertion failure

The assertion is imprecise now, and the code assumed that from the
moment an internal class was encountered that there were only internal
classes remaining. This is wrong now, and we still have to continue if
we encounter an internal class. We can only skip the remaining iterations
if the entry in the hash table is not an alias.

Author: nielsdos

ext/opcache/ZendAccelerator.c

@@ -3522,7 +3522,7 @@ static void preload_shutdown(void)
 	if (EG(class_table)) {
 		ZEND_HASH_MAP_REVERSE_FOREACH_VAL(EG(class_table), zv) {
 			zend_class_entry *ce = Z_PTR_P(zv);
-			if (ce->type == ZEND_INTERNAL_CLASS) {
+			if (ce->type == ZEND_INTERNAL_CLASS && Z_TYPE_P(zv) != IS_ALIAS_PTR) {
 				break;
 			}
 		} ZEND_HASH_MAP_FOREACH_END_DEL();
@@ -3610,7 +3610,14 @@ static void preload_move_user_classes(HashTable *src, HashTable *dst)
 	zend_hash_extend(dst, dst->nNumUsed + src->nNumUsed, 0);
 	ZEND_HASH_MAP_FOREACH_BUCKET_FROM(src, p, EG(persistent_classes_count)) {
 		zend_class_entry *ce = Z_PTR(p->val);
-		ZEND_ASSERT(ce->type == ZEND_USER_CLASS);
+
+		/* Possible with internal class aliases */
+		if (ce->type == ZEND_INTERNAL_CLASS) {
+			_zend_hash_append(dst, p->key, &p->val);
+			zend_hash_del_bucket(src, p);
+			continue;
+		}
+
 		if (ce->info.user.filename != filename) {
 			filename = ce->info.user.filename;
 			if (filename) {
@@ -3904,7 +3911,11 @@ static void preload_link(void)
 
 		ZEND_HASH_MAP_FOREACH_STR_KEY_VAL_FROM(EG(class_table), key, zv, EG(persistent_classes_count)) {
 			ce = Z_PTR_P(zv);
-			ZEND_ASSERT(ce->type != ZEND_INTERNAL_CLASS);
+
+			/* Possible with internal class aliases */
+			if (ce->type == ZEND_INTERNAL_CLASS) {
+				continue;
+			}
 
 			if (!(ce->ce_flags & (ZEND_ACC_TOP_LEVEL|ZEND_ACC_ANON_CLASS))
 					|| (ce->ce_flags & ZEND_ACC_LINKED)) {
@@ -3990,9 +4001,15 @@ static void preload_link(void)
 
 		ZEND_HASH_MAP_REVERSE_FOREACH_VAL(EG(class_table), zv) {
 			ce = Z_PTR_P(zv);
+
+			/* Possible with internal class aliases */
 			if (ce->type == ZEND_INTERNAL_CLASS) {
-				break;
+				if (Z_TYPE_P(zv) != IS_ALIAS_PTR) {
+					break; /* can stop already */
+				}
+				continue;
 			}
+
 			if ((ce->ce_flags & ZEND_ACC_LINKED) && !(ce->ce_flags & ZEND_ACC_CONSTANTS_UPDATED)) {
 				if (!(ce->ce_flags & ZEND_ACC_TRAIT)) { /* don't update traits */
 					CG(in_compilation) = true; /* prevent autoloading */
@@ -4009,7 +4026,15 @@ static void preload_link(void)
 	ZEND_HASH_MAP_FOREACH_STR_KEY_VAL_FROM(
 			EG(class_table), key, zv, EG(persistent_classes_count)) {
 		ce = Z_PTR_P(zv);
-		ZEND_ASSERT(ce->type != ZEND_INTERNAL_CLASS);
+
+		/* Possible with internal class aliases */
+		if (ce->type == ZEND_INTERNAL_CLASS) {
+			if (Z_TYPE_P(zv) != IS_ALIAS_PTR) {
+				break; /* can stop already */
+			}
+			continue;
+		}
+
 		if ((ce->ce_flags & (ZEND_ACC_TOP_LEVEL|ZEND_ACC_ANON_CLASS))
 				&& !(ce->ce_flags & ZEND_ACC_LINKED)) {
 			zend_string *lcname = zend_string_tolower(ce->name);

ext/opcache/tests/gh18567.phpt

@@ -0,0 +1,27 @@
+--TEST--
+GH-18567 (Preloading with internal class alias triggers assertion failure)
+--INI--
+opcache.enable=1
+opcache.enable_cli=1
+opcache.preload={PWD}/preload_gh18567.inc
+--EXTENSIONS--
+opcache
+--SKIPIF--
+<?php
+if (PHP_OS_FAMILY == 'Windows') die('skip Preloading is not supported on Windows');
+?>
+--FILE--
+<?php
+abstract class Test implements MyStringable {
+}
+$rc = new ReflectionClass(Test::class);
+var_dump($rc->getInterfaces());
+?>
+--EXPECT--
+array(1) {
+  ["Stringable"]=>
+  object(ReflectionClass)#2 (1) {
+    ["name"]=>
+    string(10) "Stringable"
+  }
+}

ext/opcache/tests/preload_gh18567.inc

@@ -0,0 +1,2 @@
+<?php
+class_alias('Stringable', 'MyStringable');