From 38486dcbba25c04a2cb97f7e0d6f8e32d1991d46 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Mart=C3=ADn=20Bigio?= <martinb@fb.com>
Date: Fri, 15 Jan 2016 10:31:22 -0800
Subject: [PATCH] Throw if there's an error persisting the cache

Reviewed By: davidaurelio

Differential Revision: D2824116

fb-gh-sync-id: 46b3c51a11d22e2da750f9c5a4b431a88004cd81
---
 .../src/DependencyResolver/Cache/index.js     | 22 +++++++++++--------
 1 file changed, 13 insertions(+), 9 deletions(-)

diff --git a/packager/react-packager/src/DependencyResolver/Cache/index.js b/packager/react-packager/src/DependencyResolver/Cache/index.js
index 3f601bd49..02384a202 100644
--- a/packager/react-packager/src/DependencyResolver/Cache/index.js
+++ b/packager/react-packager/src/DependencyResolver/Cache/index.js
@@ -109,18 +109,18 @@ class Cache {
       return this._persisting;
     }
 
-    var data = this._data;
-    var cacheFilepath = this._cacheFilePath;
+    const data = this._data;
+    const cacheFilepath = this._cacheFilePath;
 
-    var allPromises = getObjectValues(data)
+    const allPromises = getObjectValues(data)
       .map(record => {
-        var fieldNames = Object.keys(record.data);
-        var fieldValues = getObjectValues(record.data);
+        const fieldNames = Object.keys(record.data);
+        const fieldValues = getObjectValues(record.data);
 
         return Promise
           .all(fieldValues)
           .then(ref => {
-            var ret = Object.create(null);
+            const ret = Object.create(null);
             ret.metadata = record.metadata;
             ret.data = Object.create(null);
             fieldNames.forEach((field, index) =>
@@ -134,18 +134,22 @@ class Cache {
 
     this._persisting = Promise.all(allPromises)
       .then(values => {
-        var json = Object.create(null);
+        const json = Object.create(null);
         Object.keys(data).forEach((key, i) => {
-          if (!values[i]) {
+          // make sure the key wasn't added nor removed after we started
+          // persisting the cache
+          const value = values[i];
+          if (!value) {
             return;
           }
 
           json[key] = Object.create(null);
           json[key].metadata = data[key].metadata;
-          json[key].data = values[i].data;
+          json[key].data = value.data;
         });
         return Promise.denodeify(fs.writeFile)(cacheFilepath, JSON.stringify(json));
       })
+      .catch(e => console.error('Error while persisting cache:', e.message))
       .then(() => {
         this._persisting = null;
         return true;