Add length check to ecma_builtin_array_prototype_object_slice (#3481)

Fixes #3479

JerryScript-DCO-1.0-Signed-off-by: Peter Marki marpeter@inf.u-szeged.hu

tests/jerry/es2015/array-prototype-slice.js

@@ -0,0 +1,55 @@
+// Copyright JS Foundation and other contributors, http://js.foundation
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+// Constructor creates longer array than expected.
+class LongArray extends Array {
+    constructor(len) {
+        super (42);
+        this.fill ("foo");
+    }
+}
+
+var a = new LongArray (5);
+a.length = 5;
+var sliced = a.slice ();
+assert (sliced.length == 5);
+assert (JSON.stringify (sliced) == '["foo","foo","foo","foo","foo"]')
+
+// Constructor creates shorter array than expected.
+class ShortArray extends Array {
+    constructor(len) {
+        super (2);
+        this.fill ("bar");
+    }
+}
+
+var b = new ShortArray (8);
+b.length = 8;
+b.fill ("asd", 2);
+var sliced2 = b.slice ();
+assert (sliced2.length == 8);
+assert (JSON.stringify (sliced2) == '["bar","bar","asd","asd","asd","asd","asd","asd"]');
+
+// Constructor creates array of the expected size.
+class ExactArray extends Array {
+    constructor(len) {
+        super (len);
+        this.fill ("baz");
+    }
+}
+
+var c = new ExactArray (5);
+var sliced3 = c.slice();
+assert (sliced3.length == 5);
+assert (JSON.stringify (sliced3) == '["baz","baz","baz","baz","baz"]');

tests/jerry/es2015/regression-test-issue-3479.js

@@ -0,0 +1,21 @@
+// Copyright JS Foundation and other contributors, http://js.foundation
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+class MyObservedArray extends Array {
+    constructor() {
+        super('"use strict"; var x = "\\411";')
+    } [Symbol]() {}
+}
+
+new MyObservedArray().slice()