When a proxy's has() is true for a property, we try to look it up and if it isn't there, set it to the default value. This causes a semantically correct TypeError to be thrown from ToPropertyDescriptor.

dilijev · dilijev · commit 574fc7739c42 · 2016-04-28T13:59:52.000-07:00
diff --git a/lib/Parser/rterrors.h b/lib/Parser/rterrors.h
@@ -164,7 +164,7 @@ RT_ERROR_MSG(JSERR_Property_CannotDelete_NullOrUndefined, 5049, "Unable to delet
 RT_ERROR_MSG(JSERR_Property_VarDate, 5050, "Unable to access property '%s': type 'VarDate' does not support user-defined properties", "Object expected", kjstTypeError, JSERR_NeedObject)
 RT_ERROR_MSG(JSERR_Property_NeedFunction, 5051, "The value of the property '%s' is not a Function object", "Function expected", kjstTypeError, JSERR_NeedFunction)
 RT_ERROR_MSG(JSERR_Property_NeedFunction_NullOrUndefined, 5052, "The value of the property '%s' is null or undefined, not a Function object", "Function expected", kjstTypeError, JSERR_NeedObject)
-RT_ERROR_MSG(JSERR_Property_CannotHaveAccessorsAndValue, 5053, "", "Property cannot have both accessors and a value", kjstTypeError, VBSERR_ActionNotSupported)
+RT_ERROR_MSG(JSERR_Property_CannotHaveAccessorsAndValue, 5053, "", "Invalid property descriptor: cannot both specify accessors and a 'value' attribute", kjstTypeError, VBSERR_ActionNotSupported)
 
 RT_ERROR_MSG(JSERR_This_NullOrUndefined, 5054, "%s: 'this' is null or undefined", "'this' is null or undefined", kjstTypeError, JSERR_NeedObject) // {Locked="\'this\'"}
 RT_ERROR_MSG(JSERR_This_NeedObject, 5055, "%s: 'this' is not an Object", "Object expected", kjstTypeError, JSERR_NeedObject) // {Locked="\'this\'"}
diff --git a/lib/Runtime/Language/JavascriptOperators.cpp b/lib/Runtime/Language/JavascriptOperators.cpp
@@ -8686,6 +8686,11 @@ namespace Js
             {
                 descriptor->SetEnumerable(JavascriptConversion::ToBoolean(value, scriptContext) ? true : false);
             }
+            else
+            {
+                // The proxy said we have the property, so we try to read the property and get the default value.
+                descriptor->SetEnumerable(false);
+            }
         }
 
         if (JavascriptOperators::HasProperty(propertySpecObj, PropertyIds::configurable) == TRUE)
@@ -8694,6 +8699,11 @@ namespace Js
             {
                 descriptor->SetConfigurable(JavascriptConversion::ToBoolean(value, scriptContext) ? true : false);
             }
+            else
+            {
+                // The proxy said we have the property, so we try to read the property and get the default value.
+                descriptor->SetConfigurable(false);
+            }
         }
 
         if (JavascriptOperators::HasProperty(propertySpecObj, PropertyIds::value) == TRUE)
@@ -8702,6 +8712,11 @@ namespace Js
             {
                 descriptor->SetValue(value);
             }
+            else
+            {
+                // The proxy said we have the property, so we try to read the property and get the default value.
+                descriptor->SetValue(scriptContext->GetLibrary()->GetUndefined());
+            }
         }
 
         if (JavascriptOperators::HasProperty(propertySpecObj, PropertyIds::writable) == TRUE)
@@ -8710,6 +8725,11 @@ namespace Js
             {
                 descriptor->SetWritable(JavascriptConversion::ToBoolean(value, scriptContext) ? true : false);
             }
+            else
+            {
+                // The proxy said we have the property, so we try to read the property and get the default value.
+                descriptor->SetWritable(false);
+            }
         }
 
         if (JavascriptOperators::HasProperty(propertySpecObj, PropertyIds::get) == TRUE)
@@ -8722,6 +8742,11 @@ namespace Js
                 }
                 descriptor->SetGetter(value);
             }
+            else
+            {
+                // The proxy said we have the property, so we try to read the property and get the default value.
+                descriptor->SetGetter(scriptContext->GetLibrary()->GetUndefined());
+            }
         }
 
         if (JavascriptOperators::HasProperty(propertySpecObj, PropertyIds::set) == TRUE)
@@ -8734,6 +8759,11 @@ namespace Js
                 }
                 descriptor->SetSetter(value);
             }
+            else
+            {
+                // The proxy said we have the property, so we try to read the property and get the default value.
+                descriptor->SetSetter(scriptContext->GetLibrary()->GetUndefined());
+            }
         }
 
         return TRUE;

Original file line number	Diff line number	Diff line change
`@@ -8686,6 +8686,11 @@ namespace Js`
`8686`	`8686`	`{`
`8687`	`8687`	`descriptor->SetEnumerable(JavascriptConversion::ToBoolean(value, scriptContext) ? true : false);`
`8688`	`8688`	`}`
	`8689`	`+ else`
	`8690`	`+ {`
	`8691`	`+ // The proxy said we have the property, so we try to read the property and get the default value.`
	`8692`	`+ descriptor->SetEnumerable(false);`
	`8693`	`+ }`
`8689`	`8694`	`}`
`8690`	`8695`
`8691`	`8696`	`if (JavascriptOperators::HasProperty(propertySpecObj, PropertyIds::configurable) == TRUE)`
`@@ -8694,6 +8699,11 @@ namespace Js`
`8694`	`8699`	`{`
`8695`	`8700`	`descriptor->SetConfigurable(JavascriptConversion::ToBoolean(value, scriptContext) ? true : false);`
`8696`	`8701`	`}`
	`8702`	`+ else`
	`8703`	`+ {`
	`8704`	`+ // The proxy said we have the property, so we try to read the property and get the default value.`
	`8705`	`+ descriptor->SetConfigurable(false);`
	`8706`	`+ }`
`8697`	`8707`	`}`
`8698`	`8708`
`8699`	`8709`	`if (JavascriptOperators::HasProperty(propertySpecObj, PropertyIds::value) == TRUE)`
`@@ -8702,6 +8712,11 @@ namespace Js`
`8702`	`8712`	`{`
`8703`	`8713`	`descriptor->SetValue(value);`
`8704`	`8714`	`}`
	`8715`	`+ else`
	`8716`	`+ {`
	`8717`	`+ // The proxy said we have the property, so we try to read the property and get the default value.`
	`8718`	`+ descriptor->SetValue(scriptContext->GetLibrary()->GetUndefined());`
	`8719`	`+ }`
`8705`	`8720`	`}`
`8706`	`8721`
`8707`	`8722`	`if (JavascriptOperators::HasProperty(propertySpecObj, PropertyIds::writable) == TRUE)`
`@@ -8710,6 +8725,11 @@ namespace Js`
`8710`	`8725`	`{`
`8711`	`8726`	`descriptor->SetWritable(JavascriptConversion::ToBoolean(value, scriptContext) ? true : false);`
`8712`	`8727`	`}`
	`8728`	`+ else`
	`8729`	`+ {`
	`8730`	`+ // The proxy said we have the property, so we try to read the property and get the default value.`
	`8731`	`+ descriptor->SetWritable(false);`
	`8732`	`+ }`
`8713`	`8733`	`}`
`8714`	`8734`
`8715`	`8735`	`if (JavascriptOperators::HasProperty(propertySpecObj, PropertyIds::get) == TRUE)`
`@@ -8722,6 +8742,11 @@ namespace Js`
`8722`	`8742`	`}`
`8723`	`8743`	`descriptor->SetGetter(value);`
`8724`	`8744`	`}`
	`8745`	`+ else`
	`8746`	`+ {`
	`8747`	`+ // The proxy said we have the property, so we try to read the property and get the default value.`
	`8748`	`+ descriptor->SetGetter(scriptContext->GetLibrary()->GetUndefined());`
	`8749`	`+ }`
`8725`	`8750`	`}`
`8726`	`8751`
`8727`	`8752`	`if (JavascriptOperators::HasProperty(propertySpecObj, PropertyIds::set) == TRUE)`
`@@ -8734,6 +8759,11 @@ namespace Js`
`8734`	`8759`	`}`
`8735`	`8760`	`descriptor->SetSetter(value);`
`8736`	`8761`	`}`
	`8762`	`+ else`
	`8763`	`+ {`
	`8764`	`+ // The proxy said we have the property, so we try to read the property and get the default value.`
	`8765`	`+ descriptor->SetSetter(scriptContext->GetLibrary()->GetUndefined());`
	`8766`	`+ }`
`8737`	`8767`	`}`
`8738`	`8768`
`8739`	`8769`	`return TRUE;`