From b3bcd7310263121732fd052ae8f247f90d7bd406 Mon Sep 17 00:00:00 2001
From: Nikolai Tillmann <nikolait@fb.com>
Date: Fri, 31 Aug 2018 02:25:10 -0700
Subject: [PATCH] Add invariant that an object with modified properties must be
 valid. (#2278)

Summary:
Release notes: None

The uncovered bug is tracked in #2279.
Pull Request resolved: https://github.com/facebook/prepack/pull/2278

Differential Revision: D9472482

Pulled By: NTillmann

fbshipit-source-id: 5d6e24abd76fd83e9078c3908fa0be0e7f0b2c51
---
 src/serializer/ResidualHeapVisitor.js | 24 ++++++++++++++----------
 src/utils/generator.js                |  1 +
 src/values/ObjectValue.js             |  5 +++++
 3 files changed, 20 insertions(+), 10 deletions(-)

diff --git a/src/serializer/ResidualHeapVisitor.js b/src/serializer/ResidualHeapVisitor.js
index 3eaddbeb8e..365780d005 100644
--- a/src/serializer/ResidualHeapVisitor.js
+++ b/src/serializer/ResidualHeapVisitor.js
@@ -847,6 +847,7 @@ export class ResidualHeapVisitor {
   }
 
   visitValueObject(val: ObjectValue): void {
+    invariant(val.isValid());
     this._registerAdditionalRoot(val);
     if (isReactElement(val)) {
       this.residualReactElementVisitor.visitReactElement(val);
@@ -1038,17 +1039,20 @@ export class ResidualHeapVisitor {
       this.postProcessValue(equivalentValue);
       return (equivalentValue: any);
     }
-    if (val instanceof ObjectValue && isReactElement(val)) {
-      if (val.temporalAlias !== undefined) {
-        return this.visitEquivalentValue(val.temporalAlias);
+    if (val instanceof ObjectValue) {
+      invariant(val.isValid());
+      if (isReactElement(val)) {
+        if (val.temporalAlias !== undefined) {
+          return this.visitEquivalentValue(val.temporalAlias);
+        }
+        let equivalentReactElementValue = this.residualReactElementVisitor.reactElementEquivalenceSet.add(val);
+        if (this._mark(equivalentReactElementValue)) this.visitValueObject(equivalentReactElementValue);
+        return (equivalentReactElementValue: any);
+      } else if (isReactPropsObject(val)) {
+        let equivalentReactPropsValue = this.residualReactElementVisitor.reactPropsEquivalenceSet.add(val);
+        if (this._mark(equivalentReactPropsValue)) this.visitValueObject(equivalentReactPropsValue);
+        return (equivalentReactPropsValue: any);
       }
-      let equivalentReactElementValue = this.residualReactElementVisitor.reactElementEquivalenceSet.add(val);
-      if (this._mark(equivalentReactElementValue)) this.visitValueObject(equivalentReactElementValue);
-      return (equivalentReactElementValue: any);
-    } else if (val instanceof ObjectValue && isReactPropsObject(val)) {
-      let equivalentReactPropsValue = this.residualReactElementVisitor.reactPropsEquivalenceSet.add(val);
-      if (this._mark(equivalentReactPropsValue)) this.visitValueObject(equivalentReactPropsValue);
-      return (equivalentReactPropsValue: any);
     }
     this.visitValue(val);
     return val;
diff --git a/src/utils/generator.js b/src/utils/generator.js
index 371513ee32..71eba29a89 100644
--- a/src/utils/generator.js
+++ b/src/utils/generator.js
@@ -614,6 +614,7 @@ export class Generator {
 
     for (let propertyBinding of modifiedProperties.keys()) {
       let object = propertyBinding.object;
+      invariant(object.isValid());
       if (createdObjects.has(object)) continue; // Created Object's binding
       if (ObjectValue.refuseSerializationOnPropertyBinding(propertyBinding)) continue; // modification to internal state
       // modifications to intrinsic objects are tracked in the generator
diff --git a/src/values/ObjectValue.js b/src/values/ObjectValue.js
index e912926898..e97845b676 100644
--- a/src/values/ObjectValue.js
+++ b/src/values/ObjectValue.js
@@ -308,6 +308,11 @@ export default class ObjectValue extends ConcreteValue {
   // never be serialized.
   refuseSerialization: boolean;
 
+  // Checks whether effects are properly applied.
+  isValid(): boolean {
+    return this._isPartial !== undefined;
+  }
+
   equals(x: Value): boolean {
     return this === x;
   }