Fix #1915 Update property

kernels/ZendEngine3/object.c

@@ -750,7 +750,9 @@ int zephir_update_property_array_append(zval *object, char *property, unsigned i
 				zval new_zv;
 				ZVAL_DUP(&new_zv, &tmp);
 				ZVAL_COPY_VALUE(&tmp, &new_zv);
-				Z_TRY_DELREF(new_zv);
+				if (Z_REFCOUNT(tmp) > 1) {
+				    Z_TRY_DELREF(new_zv);
+				}
 				separated = 1;
 			}
 		}

test/properties/propertyupdate.zep

@@ -0,0 +1,10 @@
+namespace Test\Properties;
+
+class PropertyUpdate
+{
+    public p1;
+
+    public function update1() {
+        let this->p1[] = "aaa";
+    }
+}

unit-tests/Extension/Properties/PropertyUpdateTest.php

@@ -0,0 +1,28 @@
+<?php
+
+/*
+ * This file is part of the Zephir.
+ *
+ * (c) Zephir Team <[email protected]>
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+namespace Extension\Properties;
+
+use PHPUnit\Framework\TestCase;
+use Test\Properties\PropertyUpdate;
+
+class PropertyUpdateTest extends TestCase
+{
+    public function testUpdate11()
+    {
+        // before fixed. Assertion failed: (((ht)->gc.refcount == 1) || ((ht)->u.flags & (1<<6))), function _zend_hash_index_add_or_update_i
+        $t = new PropertyUpdate();
+        $t->p1 = [111];
+        $t->update1();
+
+        $this->assertSame($t->p1, [111, 'aaa']);
+    }
+}