Tests for Proxy property descriptor behavior

Also add property descriptor print helpers and change a few test cases
to use them.

tests/ecmascript/test-bi-array-proto-reverse.js

@@ -1,27 +1,6 @@
 // XXX: shared test utils
 
-function formatValue(v) {
-    if (typeof v === 'function') {
-        return 'function';
-    }
-    return typeof(v) + ':' + String(v);
-}
-
-function printDescriptor(obj, key) {
-    var pd = Object.getOwnPropertyDescriptor(obj, key);
-    if (!pd) {
-        print('key=' + key, 'nonexistent');
-        return;
-    }
-
-    print('key=' + key,
-          'value=' + formatValue(pd.value),
-          'writable=' + formatValue(pd.writable),
-          'enumerable=' + formatValue(pd.enumerable),
-          'configurable=' + formatValue(pd.configurable),
-          'get=' + formatValue(pd.get),
-          'set=' + formatValue(pd.set));
-}
+/*@include util-object.js@*/
 
 function dumpValue(x) {
     var i, n, clipped;
@@ -157,33 +136,33 @@ try {
 /*===
 attributes
 true true false false false true false true
-key=0 value=undefined:undefined writable=undefined:undefined enumerable=boolean:false configurable=boolean:true get=function set=function
-key=1 value=undefined:undefined writable=undefined:undefined enumerable=boolean:false configurable=boolean:true get=function set=function
-key=2 nonexistent
-key=3 nonexistent
-key=4 nonexistent
-key=5 value=undefined:undefined writable=undefined:undefined enumerable=boolean:true configurable=boolean:true get=function set=function
-key=6 nonexistent
-key=7 value=undefined:undefined writable=undefined:undefined enumerable=boolean:true configurable=boolean:true get=function set=function
+key: 0, desc: get=function,set=function,enumerable=false,configurable=true
+key: 1, desc: get=function,set=function,enumerable=false,configurable=true
+key: 2, desc: none
+key: 3, desc: none
+key: 4, desc: none
+key: 5, desc: get=function,set=function,enumerable=true,configurable=true
+key: 6, desc: none
+key: 7, desc: get=function,set=function,enumerable=true,configurable=true
 get 0
 get 7
 set 0 val7
 set 7 val0
 get 1
 get 5
 true false true false false false true true
-key=0 value=undefined:undefined writable=undefined:undefined enumerable=boolean:false configurable=boolean:true get=function set=function
-key=1 nonexistent
-key=2 value=string:val5 writable=boolean:true enumerable=boolean:true configurable=boolean:true get=undefined:undefined set=undefined:undefined
-key=3 nonexistent
-key=4 nonexistent
-key=5 nonexistent
-key=6 value=string:val1 writable=boolean:true enumerable=boolean:true configurable=boolean:true get=undefined:undefined set=undefined:undefined
-key=7 value=undefined:undefined writable=undefined:undefined enumerable=boolean:true configurable=boolean:true get=function set=function
-key=0 value=string:foo writable=boolean:true enumerable=boolean:false configurable=boolean:true get=undefined:undefined set=undefined:undefined
-key=1 nonexistent
-key=0 value=string:foo writable=boolean:true enumerable=boolean:false configurable=boolean:true get=undefined:undefined set=undefined:undefined
-key=1 nonexistent
+key: 0, desc: get=function,set=function,enumerable=false,configurable=true
+key: 1, desc: none
+key: 2, desc: value="val5",writable=true,enumerable=true,configurable=true
+key: 3, desc: none
+key: 4, desc: none
+key: 5, desc: none
+key: 6, desc: value="val1",writable=true,enumerable=true,configurable=true
+key: 7, desc: get=function,set=function,enumerable=true,configurable=true
+key: 0, desc: value="foo",writable=true,enumerable=false,configurable=true
+key: 1, desc: none
+key: 0, desc: value="foo",writable=true,enumerable=false,configurable=true
+key: 1, desc: none
 ===*/
 
 print('attributes');
@@ -245,7 +224,7 @@ function attributesTest() {
           t.hasOwnProperty(6), t.hasOwnProperty(7));
 
     for (i = 0; i < 8; i++) {
-        printDescriptor(t, String(i));
+        printKeyPropDesc(t, String(i));
     }
 
     t.reverse();
@@ -256,7 +235,7 @@ function attributesTest() {
           t.hasOwnProperty(6), t.hasOwnProperty(7));
 
     for (i = 0; i < 8; i++) {
-        printDescriptor(t, String(i));
+        printKeyPropDesc(t, String(i));
     }
 
     // Here, '0' is not enumerable, but when it gets swapped to position 1,
@@ -269,11 +248,11 @@ function attributesTest() {
         '0': { value: 'foo', writable: true, enumerable: false, configurable: true },
         'length': { value: 2 }
     });
-    printDescriptor(t, '0');
-    printDescriptor(t, '1');
+    printKeyPropDesc(t, '0');
+    printKeyPropDesc(t, '1');
     [].reverse();
-    printDescriptor(t, '0');
-    printDescriptor(t, '1');
+    printKeyPropDesc(t, '0');
+    printKeyPropDesc(t, '1');
 }
 
 try {

tests/ecmascript/test-bi-proxy-defineproperty.js

@@ -0,0 +1,40 @@
+/*
+ *  Proxy (ES2015) 'defineProperty'.
+ */
+
+/*@include util-object.js@*/
+
+/*===
+value=123,writable=false,enumerable=false,configurable=true
+get=function,set=function,enumerable=false,configurable=true
+===*/
+
+function passThroughTest() {
+    var T = {};
+    var P = new Proxy(T, {});
+    var pd;
+
+    Object.defineProperty(P, 'foo', {
+        value: 123,
+        writable: false,
+        enumerable: false,
+        configurable: true
+    });
+    Object.defineProperty(P, 'bar', {
+        get: function getter() {},
+        set: function setter() {},
+        enumerable: false,
+        configurable: true
+    });
+
+    pd = Object.getOwnPropertyDescriptor(T, 'foo');
+    printPropDesc(pd);
+    pd = Object.getOwnPropertyDescriptor(T, 'bar');
+    printPropDesc(pd);
+}
+
+try {
+    passThroughTest();
+} catch (e) {
+    print(e.stack || e);
+}

tests/ecmascript/test-bi-proxy-getownpropertydescriptor.js

@@ -0,0 +1,53 @@
+/*
+ *  Proxy (ES2015) 'getOwnPropertyDescriptor'.
+ */
+
+/*@include util-object.js@*/
+
+/*===
+value=123,writable=true,enumerable=false,configurable=true
+get=function,enumerable=true,configurable=false
+set=function,enumerable=false,configurable=false
+get=function,set=function,enumerable=true,configurable=true
+value=123,writable=true,enumerable=false,configurable=true
+get=function,enumerable=true,configurable=false
+set=function,enumerable=false,configurable=false
+get=function,set=function,enumerable=true,configurable=true
+===*/
+
+function passThroughTest() {
+    var T = {};
+    var P = new Proxy(T, {});
+    var pd;
+
+    Object.defineProperty(T, 'foo', { value: 123, writable: true, enumerable: false, configurable: true });
+    Object.defineProperty(T, 'bar', { get: function getter() {}, enumerable: true, configurable: false });
+    Object.defineProperty(T, 'quux', { set: function setter() {}, enumerable: false, configurable: false });
+    Object.defineProperty(T, 'baz', { get: function getter() {}, set: function setter() {}, enumerable: true, configurable: true });
+
+    pd = Object.getOwnPropertyDescriptor(T, 'foo');
+    printPropDesc(pd);
+    pd = Object.getOwnPropertyDescriptor(T, 'bar');
+    printPropDesc(pd);
+    pd = Object.getOwnPropertyDescriptor(T, 'quux');
+    printPropDesc(pd);
+    pd = Object.getOwnPropertyDescriptor(T, 'baz');
+    printPropDesc(pd);
+
+    // As of Duktape 2.2 getOwnPropertyDescriptor() properly passes through
+    // to the target object.
+    pd = Object.getOwnPropertyDescriptor(P, 'foo');
+    printPropDesc(pd);
+    pd = Object.getOwnPropertyDescriptor(P, 'bar');
+    printPropDesc(pd);
+    pd = Object.getOwnPropertyDescriptor(P, 'quux');
+    printPropDesc(pd);
+    pd = Object.getOwnPropertyDescriptor(P, 'baz');
+    printPropDesc(pd);
+}
+
+try {
+    passThroughTest();
+} catch (e) {
+    print(e.stack || e);
+}

tests/ecmascript/test-bi-proxy-virtualized-enum.js

@@ -0,0 +1,62 @@
+/*
+ *  Example of virtualizing enumeration using a Proxy.
+ */
+
+/*===
+ownKeys trap: true
+getOwnPropertyDescriptor trap: true true string 0
+getOwnPropertyDescriptor trap: true true string 1
+getOwnPropertyDescriptor trap: true true string 2
+getOwnPropertyDescriptor trap: true true string 3
+getOwnPropertyDescriptor trap: true true string 4
+getOwnPropertyDescriptor trap: true true string noSuch
+getOwnPropertyDescriptor trap: true true string length
+0
+1
+2
+3
+4
+noSuch
+===*/
+
+function test() {
+    var target = [ 'foo', 'bar', 'quux' ];
+    var handler = {
+        ownKeys: function () {
+            // The ownKeys result set is validated against the Proxy to ensure
+            // enumerated keys are enumerable; unless a getOwnPropertyDescriptor
+            // trap exists these checks will be made against the target which
+            // means non-existent properties won't be enumerated.§
+            print('ownKeys trap:', this === handler);
+            return [ '0', '1', '2', '3', '4', 'noSuch', 'length' ]
+        },
+        getOwnPropertyDescriptor: function (targ, key) {
+            // Cannot report 'length' as enumerable (that would violate
+            // getOwnPropertyDescriptor trap constraints).  However,
+            // Duktape 2.2 (at least) won't enforce that constraint yet.
+            print('getOwnPropertyDescriptor trap:', this === handler, targ === target, typeof key, key);
+            if (key === 'length') {
+                return Object.getOwnPropertyDescriptor(target, key);
+            }
+            return {
+                value: target[key],
+                enumerable: true,
+                writable: true,
+                configurable: true
+            };
+        }
+    };
+    var proxy = new Proxy(target, handler);
+
+    // Without 'getOwnPropertyDescriptor' trap the only keys visible would be
+    // '0', '1', and '2' which backing in the target object.
+    for (var k in proxy) {
+        print(k);
+    }
+}
+
+try {
+    test();
+} catch (e) {
+    print(e.stack || e);
+}

tests/ecmascript/test-dev-array-property-attrs.js

@@ -3,31 +3,29 @@
  *  and without an internal "array part".
  */
 
-function printDesc(desc) {
-    print(desc.writable, desc.enumerable, desc.configurable);
-}
+/*@include util-object.js@*/
 
 /*===
-true true true
-true true true
-true true true
-true true true
-true true true
-true true true
-true true true
+value=1,writable=true,enumerable=true,configurable=true
+value=2,writable=true,enumerable=true,configurable=true
+value=3,writable=true,enumerable=true,configurable=true
+value=1,writable=true,enumerable=true,configurable=true
+value=2,writable=true,enumerable=true,configurable=true
+value=3,writable=true,enumerable=true,configurable=true
+value=4,writable=true,enumerable=true,configurable=true
 ===*/
 
 /* array is initially dense (array part exists) */
 a = [1,2,3];
 
-printDesc(Object.getOwnPropertyDescriptor(a, '0'));
-printDesc(Object.getOwnPropertyDescriptor(a, '1'));
-printDesc(Object.getOwnPropertyDescriptor(a, '2'));
+printPropDesc(Object.getOwnPropertyDescriptor(a, '0'));
+printPropDesc(Object.getOwnPropertyDescriptor(a, '1'));
+printPropDesc(Object.getOwnPropertyDescriptor(a, '2'));
 
 /* force array to be sparse (array part is abandoned) */
 a[10000] = 4;
 
-printDesc(Object.getOwnPropertyDescriptor(a, '0'));
-printDesc(Object.getOwnPropertyDescriptor(a, '1'));
-printDesc(Object.getOwnPropertyDescriptor(a, '2'));
-printDesc(Object.getOwnPropertyDescriptor(a, '10000'));
+printPropDesc(Object.getOwnPropertyDescriptor(a, '0'));
+printPropDesc(Object.getOwnPropertyDescriptor(a, '1'));
+printPropDesc(Object.getOwnPropertyDescriptor(a, '2'));
+printPropDesc(Object.getOwnPropertyDescriptor(a, '10000'));

tests/ecmascript/util-object.js

@@ -47,3 +47,50 @@ function getValuePublicType(val) {
 function getValueInternalTag(val) {
     return getDuktapeInfoField(val, 1, 'itag');
 }
+
+// String convert a descriptor object.
+function propDescToString(pd) {
+    function fmt(v) {
+        if (typeof v === 'function') {
+            return 'function';
+        }
+        return Duktape.enc('jx', v);
+    }
+
+    if (!pd) {
+        return 'none';
+    }
+
+    var res = [];
+    if (pd.value !== void 0) {
+        res.push('value=' + fmt(pd.value));
+    }
+    if (pd.get !== void 0) {
+        res.push('get=' + fmt(pd.get));
+    }
+    if (pd.set !== void 0) {
+        res.push('set=' + fmt(pd.set));
+    }
+    if (pd.writable !== void 0) {
+        res.push('writable=' + fmt(pd.writable));
+    }
+    if (pd.enumerable !== void 0) {
+        res.push('enumerable=' + fmt(pd.enumerable));
+    }
+    if (pd.configurable !== void 0) {
+        res.push('configurable=' + fmt(pd.configurable));
+    }
+
+    return res.join(',');
+}
+
+// Print a descriptor object.
+function printPropDesc(pd) {
+    print(propDescToString(pd));
+}
+
+// Print a key and a related property descriptor.
+function printKeyPropDesc(obj, key) {
+    var pd = Object.getOwnPropertyDescriptor(obj, key);
+    print('key: ' + key + ', desc: ' + propDescToString(pd));
+}