In strict mode throw type error when set/deleteProperty trap handler return falsy value.

Author: akroshg

lib/Parser/rterrors.h

@@ -365,6 +365,7 @@ RT_ERROR_MSG(JSERR_InvalidIteratorObject, 5672, "%s : Invalid iterator object",
 RT_ERROR_MSG(JSERR_NoAccessors, 5673, "Invalid property descriptor: accessors not supported on this object", "", kjstTypeError, 0)
 RT_ERROR_MSG(JSERR_RegExpInvalidEscape, 5674, "", "Invalid regular expression: invalid escape in unicode pattern", kjstSyntaxError, 0)
 RT_ERROR_MSG(JSERR_RegExpTooManyCapturingGroups, 5675, "", "Regular expression cannot have more than 32,767 capturing groups", kjstRangeError, 0)
+RT_ERROR_MSG(JSERR_ProxyHandlerReturnedFalse, 5676, "Proxy %s handler returned false", "Proxy handler returned false", kjstTypeError, 0)
 
 //Host errors
 RT_ERROR_MSG(JSERR_HostMaybeMissingPromiseContinuationCallback, 5700, "", "Host may not have set any promise continuation callback. Promises may not be executed.", kjstTypeError, 0)

lib/Runtime/Language/JavascriptOperators.cpp

@@ -2326,7 +2326,7 @@ using namespace Js;
                         PropertyValueInfo::SetNoCache(info, proxy);
                         PropertyValueInfo::DisablePrototypeCache(info, proxy);
                     }
-                    return proxy->SetPropertyTrap(receiver, JavascriptProxy::SetPropertyTrapKind::SetPropertyWPCacheKind, propertyKey, newValue, requestContext);
+                    return proxy->SetPropertyTrap(receiver, JavascriptProxy::SetPropertyTrapKind::SetPropertyWPCacheKind, propertyKey, newValue, requestContext, propertyOperationFlags);
                 }
                 else
                 {
@@ -2410,7 +2410,7 @@ using namespace Js;
                     JavascriptProxy* proxy = JavascriptProxy::FromVar(setterValueOrProxy);
                     const PropertyRecord* propertyRecord = nullptr;
                     proxy->PropertyIdFromInt(index, &propertyRecord);
-                    return proxy->SetPropertyTrap(receiver, JavascriptProxy::SetPropertyTrapKind::SetItemOnTaggedNumberKind, propertyRecord->GetPropertyId(), newValue, requestContext);
+                    return proxy->SetPropertyTrap(receiver, JavascriptProxy::SetPropertyTrapKind::SetItemOnTaggedNumberKind, propertyRecord->GetPropertyId(), newValue, requestContext, propertyOperationFlags);
                 }
                 else
                 {
@@ -2458,7 +2458,7 @@ using namespace Js;
                 {
                     Assert(JavascriptProxy::Is(setterValueOrProxy));
                     JavascriptProxy* proxy = JavascriptProxy::FromVar(setterValueOrProxy);
-                    return proxy->SetPropertyTrap(receiver, JavascriptProxy::SetPropertyTrapKind::SetPropertyOnTaggedNumberKind, propertyId, newValue, requestContext);
+                    return proxy->SetPropertyTrap(receiver, JavascriptProxy::SetPropertyTrapKind::SetPropertyOnTaggedNumberKind, propertyId, newValue, requestContext, propertyOperationFlags);
                 }
                 else
                 {
@@ -2549,7 +2549,7 @@ using namespace Js;
                 PropertyValueInfo::SetNoCache(info, proxy);
                 PropertyValueInfo::DisablePrototypeCache(info, proxy); // We can't cache prototype property either
 
-                *result = proxy->SetPropertyTrap(receiver, JavascriptProxy::SetPropertyTrapKind::SetPropertyKind, propertyId, newValue, requestContext);
+                *result = proxy->SetPropertyTrap(receiver, JavascriptProxy::SetPropertyTrapKind::SetPropertyKind, propertyId, newValue, requestContext, propertyOperationFlags);
                 return true;
             }
             else
@@ -3305,7 +3305,7 @@ using namespace Js;
                 JavascriptProxy* proxy = JavascriptProxy::FromVar(setterValueOrProxy);
                 const PropertyRecord* propertyRecord = nullptr;
                 proxy->PropertyIdFromInt(index, &propertyRecord);
-                return proxy->SetPropertyTrap(receiver, JavascriptProxy::SetPropertyTrapKind::SetItemKind, propertyRecord->GetPropertyId(), value, scriptContext, skipPrototypeCheck);
+                return proxy->SetPropertyTrap(receiver, JavascriptProxy::SetPropertyTrapKind::SetItemKind, propertyRecord->GetPropertyId(), value, scriptContext, propertyOperationFlags, skipPrototypeCheck);
             }
             else
             {

lib/Runtime/Library/JavascriptProxy.cpp

@@ -827,6 +827,10 @@ namespace Js
         BOOL trapResult = JavascriptConversion::ToBoolean(deletePropertyResult, requestContext);
         if (!trapResult)
         {
+            if (flags & PropertyOperation_StrictMode)
+            {
+                JavascriptError::ThrowTypeError(requestContext, JSERR_ProxyHandlerReturnedFalse, _u("deleteProperty"));
+            }
             return trapResult;
         }
 
@@ -1775,15 +1779,15 @@ namespace Js
     }
 
 
-    BOOL JavascriptProxy::SetPropertyTrap(Var receiver, SetPropertyTrapKind setPropertyTrapKind, Js::JavascriptString * propertyNameString, Var newValue, ScriptContext* requestContext)
+    BOOL JavascriptProxy::SetPropertyTrap(Var receiver, SetPropertyTrapKind setPropertyTrapKind, Js::JavascriptString * propertyNameString, Var newValue, ScriptContext* requestContext, PropertyOperationFlags propertyOperationFlags)
     {
         const PropertyRecord* propertyRecord;
         requestContext->GetOrAddPropertyRecord(propertyNameString, &propertyRecord);
-        return SetPropertyTrap(receiver, setPropertyTrapKind, propertyRecord->GetPropertyId(), newValue, requestContext);
+        return SetPropertyTrap(receiver, setPropertyTrapKind, propertyRecord->GetPropertyId(), newValue, requestContext, propertyOperationFlags);
 
     }
 
-    BOOL JavascriptProxy::SetPropertyTrap(Var receiver, SetPropertyTrapKind setPropertyTrapKind, PropertyId propertyId, Var newValue, ScriptContext* requestContext, BOOL skipPrototypeCheck)
+    BOOL JavascriptProxy::SetPropertyTrap(Var receiver, SetPropertyTrapKind setPropertyTrapKind, PropertyId propertyId, Var newValue, ScriptContext* requestContext, PropertyOperationFlags propertyOperationFlags, BOOL skipPrototypeCheck)
     {
         PROBE_STACK(GetScriptContext(), Js::Constants::MinStackDefault);
 
@@ -1865,6 +1869,11 @@ namespace Js
         BOOL setResult = JavascriptConversion::ToBoolean(setPropertyResult, requestContext);
         if (!setResult)
         {
+            if (propertyOperationFlags & PropertyOperation_StrictMode)
+            {
+                JavascriptError::ThrowTypeError(requestContext, JSERR_ProxyHandlerReturnedFalse, _u("set"));
+            }
+
             return setResult;
         }
 

lib/Runtime/Library/JavascriptProxy.h

@@ -154,8 +154,8 @@ namespace Js
         virtual Var GetTypeOfString(ScriptContext* requestContext) override;
 
         bool IsRevoked() const;
-        BOOL SetPropertyTrap(Var receiver, SetPropertyTrapKind setPropertyTrapKind, PropertyId propertyId, Var newValue, ScriptContext* requestContext, BOOL skipPrototypeCheck = FALSE);
-        BOOL SetPropertyTrap(Var receiver, SetPropertyTrapKind setPropertyTrapKind, Js::JavascriptString * propertyString, Var newValue, ScriptContext* requestContext);
+        BOOL SetPropertyTrap(Var receiver, SetPropertyTrapKind setPropertyTrapKind, PropertyId propertyId, Var newValue, ScriptContext* requestContext, PropertyOperationFlags propertyOperationFlags, BOOL skipPrototypeCheck = FALSE);
+        BOOL SetPropertyTrap(Var receiver, SetPropertyTrapKind setPropertyTrapKind, Js::JavascriptString * propertyString, Var newValue, ScriptContext* requestContext, PropertyOperationFlags propertyOperationFlags);
 
         void PropertyIdFromInt(uint32 index, PropertyRecord const** propertyRecord);
 

test/Bugs/misc_bugs.js

@@ -165,6 +165,15 @@ var tests = [
         assert.areEqual([1], eval("let {x} = {}; [x] = [1]"));
     }
   },
+  {
+    name: "Strict Mode : throw type error when the handler returns falsy value",
+    body: function () {
+        assert.throws(() => {"use strict"; let p1 = new Proxy({}, { set() {}}); p1.foo = 1;}, TypeError, "returning undefined on set handler is return false which will throw type error",  "Proxy set handler returned false");
+        assert.throws(() => {"use strict"; let p1 = new Proxy({}, { deleteProperty() {}}); delete p1.foo;}, TypeError, "returning undefined on deleteProperty handler is return false which will throw type error",  "Proxy deleteProperty handler returned false");
+        assert.throws(() => {"use strict"; let p1 = new Proxy({}, { set() {return false;}}); p1.foo = 1;}, TypeError, "set handler is returning false which will throw type error",  "Proxy set handler returned false");
+        assert.throws(() => {"use strict"; let p1 = new Proxy({}, { deleteProperty() {return false;}}); delete p1.foo;}, TypeError, "deleteProperty handler is returning false which will throw type error",  "Proxy deleteProperty handler returned false");
+      }
+  },
 
 ];