add unset support and more tests

Author: withinboredom

Zend/tests/data_class_007.phpt

@@ -0,0 +1,18 @@
+--TEST--
+Private properties are included in equality checks
+--FILE--
+<?php
+
+data class Length {
+    public function __construct(private float $length) {}
+}
+
+$l1 = new Length(1.0);
+$l2 = new Length(1.0);
+$l3 = new Length(2.0);
+var_dump($l1 === $l2);
+var_dump($l1 !== $l3);
+?>
+--EXPECT--
+bool(true)
+bool(true)

Zend/tests/data_class_008.phpt

@@ -0,0 +1,16 @@
+--TEST--
+Data classes can be anonymous
+--FILE--
+<?php
+
+$data = new data class(1) {
+    public function __construct(private int $value) {}
+};
+
+var_dump($data);
+?>
+--EXPECT--
+data object(class@anonymous)#1 (1) {
+  ["value":"class@anonymous":private]=>
+  int(1)
+}

Zend/tests/data_class_009.phpt

@@ -0,0 +1,20 @@
+--TEST--
+unset triggers copy-on-write
+--FILE--
+<?php
+
+$data = new data class(1) {
+    public function __construct(public int $value) {}
+};
+
+$copy = $data;
+unset($copy->value);
+var_dump($data !== $copy);
+var_dump($data);
+?>
+--EXPECT--
+bool(true)
+data object(class@anonymous)#1 (1) {
+  ["value"]=>
+  int(1)
+}

Zend/zend_vm_def.h

@@ -6863,7 +6863,19 @@ ZEND_VM_HANDLER(76, ZEND_UNSET_OBJ, VAR|UNUSED|THIS|CV, CONST|TMPVAR|CV, CACHE_S
 				break;
 			}
 		}
-		Z_OBJ_HT_P(container)->unset_property(Z_OBJ_P(container), name, ((OP2_TYPE == IS_CONST) ? CACHE_ADDR(opline->extended_value) : NULL));
+		// if this is a data class, we may need to CoW
+		zend_object *zobj = Z_OBJ_P(container);
+		if (zobj->ce->ce_flags & ZEND_ACC_DATA_CLASS) {
+			if (GC_REFCOUNT(zobj) > 1) {
+				// clone the object
+				zend_object *new_obj = zend_objects_clone_obj(zobj);
+				// set the object zval to the new object
+				ZVAL_OBJ(container, new_obj);
+				GC_DELREF(zobj);
+				zobj = new_obj;
+			}
+		}
+		Z_OBJ_HT_P(container)->unset_property(zobj, name, ((OP2_TYPE == IS_CONST) ? CACHE_ADDR(opline->extended_value) : NULL));
 		if (OP2_TYPE != IS_CONST) {
 			zend_tmp_string_release(tmp_name);
 		}