adds failing test case for #12986

Author: ju1ius

ext/zend_test/test.c

@@ -73,6 +73,22 @@ static zend_class_entry *zend_test_int_enum;
 static zend_class_entry *zend_test_magic_call;
 static zend_object_handlers zend_test_class_handlers;
 
+static ZEND_FUNCTION(zend_test_gh12986)
+{
+	ZEND_PARSE_PARAMETERS_NONE();
+	HashTable *ht = _zend_new_array_0();
+	HT_ALLOW_COW_VIOLATION(ht);
+	zval value;
+	ZVAL_LONG(&value, 1);
+	zend_hash_next_index_insert(ht, &value);
+	if (HT_FLAGS(ht) & HASH_FLAG_ALLOW_COW_VIOLATION) {
+		php_printf("OK: HASH_FLAG_ALLOW_COW_VIOLATION is preserved by zend_hash_real_init_ex\n");
+	} else {
+		php_printf("KO: HASH_FLAG_ALLOW_COW_VIOLATION was cleared by zend_hash_real_init_ex\n");
+	}
+	zend_array_release(ht);
+}
+
 static int le_throwing_resource;
 
 static ZEND_FUNCTION(zend_test_func)

ext/zend_test/test.stub.php

@@ -246,6 +246,8 @@ function zend_test_override_libxml_global_state(): void {}
 #endif
 
     function zend_test_is_pcre_bundled(): bool {}
+
+    function zend_test_gh12986(): void {}
 }
 
 namespace ZendTestNS {

ext/zend_test/test_arginfo.h

@@ -0,0 +1,12 @@
+--TEST--
+GH-12986 (HASH_FLAG_ALLOW_COW_VIOLATION is not preserved by zend_hash_real_init_ex)
+--EXTENSIONS--
+zend_test
+--FILE--
+<?php
+
+zend_test_gh12986();
+
+?>
+--EXPECT--
+OK: HASH_FLAG_ALLOW_COW_VIOLATION is preserved by zend_hash_real_init_ex