1 files changed, 61 insertions, 0 deletions
diff --git a/js/src/tests/js1_8_5/regress/regress-591846.js b/js/src/tests/js1_8_5/regress/regress-591846.js
new file mode 100644
index 0000000..44b9dc6
--- /dev/null
+++ b/js/src/tests/js1_8_5/regress/regress-591846.js
@@ -0,0 +1,61 @@
+/*
+ * Any copyright is dedicated to the Public Domain.
+ * http://creativecommons.org/licenses/publicdomain/
+ */
+
+function check(obj, name, value, readonly) {
+    // Start with a non-configurable, writable data property implemented via
+    // js::PropertyOp getter and setter.
+    var pd = Object.getOwnPropertyDescriptor(obj, name);
+
+    assertEq(pd.configurable, false, "non-configurable " + name);
+    assertEq(pd.writable, !readonly, "writable " + name);
+
+    try {
+        // Do not allow a transition from js::PropertyOp to writable js::Value
+        // data property.
+        Object.defineProperty(obj, name, {writable: true});
+        assertEq(0, 1);
+    } catch (e) {
+        assertEq('' + e, "TypeError: can't redefine non-configurable property '" + name + "'");
+    }
+
+    if (!readonly) {
+        try {
+            // Do not allow the property denoted by name to become a true data
+            // property via a descriptor that preserves the native property's
+            // writable attribute.
+            Object.defineProperty(obj, name, {value: value});
+            assertEq(0, 1);
+        } catch (e) {
+            assertEq('' + e, "TypeError: can't redefine non-configurable property '" + name + "'");
+        }
+    }
+
+    try {
+        // Do not allow the property to be frozen at some bogus value.
+        Object.defineProperty(obj, name, {value: "bogus", writable: false});
+        assertEq(0, 1);
+    } catch (e) {
+        assertEq('' + e, "TypeError: can't redefine non-configurable property '" + name + "'");
+    }
+
+    // Now make name non-writable.
+    Object.defineProperty(obj, name, {writable: false})
+
+    // Assert that the right getter result "stuck".
+    assertEq(obj[name], value);
+
+    // Test that it is operationally non-writable now.
+    obj[name] = "eek!";
+    assertEq(obj[name], value);
+}
+
+check(Object, 'caller', null, false);
+check(Object, 'arguments', null, false);
+
+// Reset RegExp.leftContext to the empty string.
+/x/.test('x');
+check(RegExp, 'leftContext', '', true);
+
+reportCompare(0, 0, "ok");