Issue 6599 - Detect data corruption of storage.local

lib/subscriptionInit.js

Index: lib/subscriptionInit.js
===================================================================
--- a/lib/subscriptionInit.js
+++ b/lib/subscriptionInit.js
@@ -34,6 +34,8 @@
 
 let firstRun;
 let subscriptionsCallback = null;
+let reinitialized = false;
+let dataCorrupted = false;
 
 /**
  * If there aren't any filters, the default subscriptions are added.
@@ -50,7 +52,7 @@
   firstRun = FilterStorage.subscriptions.length == 0;
 
   if (firstRun && (!FilterStorage.firstRun || Prefs.currentVersion))
-    exports.reinitialized = true;
+    reinitialized = true;
 
   Prefs.currentVersion = info.addonVersion;
 }
@@ -225,7 +227,7 @@
   return subscriptions;
 }
 
-function finishInitialization(subscriptions)
+function addSubscriptionsAndNotifyUser(subscriptions)
 {
   if (subscriptionsCallback)
     subscriptions = subscriptionsCallback(subscriptions);
@@ -238,47 +240,60 @@
       Synchronizer.execute(subscription);
   }
 
-  if (!Prefs.suppress_first_run_page)
+  // Show first run page or the updates page. The latter is only shown
+  // on Chromium (since the current updates page announces features that
+  // aren't new to Firefox users), and only if this version of the
+  // updates page hasn't been shown yet.
+  if (firstRun || info.platform == "chromium" &&
+                  updatesVersion > Prefs.last_updates_page_displayed)
   {
-    let page = null;
-    if (firstRun)
-    {
-      page = "firstRun.html";
-    }
-    // For now we're limiting the updates page to users of
-    // Chromium-based browsers to gage its impact
-    else if (info.platform == "chromium" &&
-             updatesVersion > Prefs.last_updates_page_displayed)
+    return Prefs.set("last_updates_page_displayed", updatesVersion).catch(() =>
     {
-      page = "updates.html";
-    }
-
-    if (page)
+      dataCorrupted = true;
+    }).then(() =>
     {
-      browser.tabs.create({url: browser.extension.getURL(page)});
-
-      // For new users and users that have already seen this updates page we
-      // want to avoid showing it again for subsequent updates.
-      Prefs.last_updates_page_displayed = updatesVersion;
-    }
+      if (!Prefs.suppress_first_run_page)
+      {
+        // Always show the first run page if a data corruption was detected
+        // (either through failure of reading from or writing to storage.local).
+        // The first run page notifies the user about the data corruption.
+        let url;
+        if (firstRun || dataCorrupted)
+          url = "firstRun.html";
+        else
+          url = "updates.html";
+        browser.tabs.create({url});
+      }
+    });
   }
-
-  initNotifications();
 }
 
-Promise.all([FilterNotifier.once("load"),
-             Prefs.untilLoaded]).then(detectFirstRun)
-                                .then(getSubscriptions)
-                                .then(finishInitialization);
+Promise.all([
+  FilterNotifier.once("load"),
+  Prefs.untilLoaded.catch(() => { dataCorrupted = true; })
+]).then(detectFirstRun)
+  .then(getSubscriptions)
+  .then(addSubscriptionsAndNotifyUser)
+  // We have to require the "uninstall" module on demand,
+  // as the "uninstall" module in turn requires this module.
+  .then(() => { require("./uninstall").setUninstallURL() })
+  .then(initNotifications);
 
 /**
- * Indicates whether the default filter subscriptions have been added
- * again because there weren't any subscriptions even though this wasn't
+ * Gets a value indicating whether the default filter subscriptions have been
+ * added again because there weren't any subscriptions even though this wasn't
  * the first run.
  *
- * @type {boolean}
+ * @return {boolean}
  */
-exports.reinitialized = false;
+exports.isReinitialized = () => reinitialized;
+
+/**
+ * Gets a value indicating whether a data corruption was detected.
+ *
+ * @return {boolean}
+ */
+exports.isDataCorrupted = () => dataCorrupted;
 
 /**
  * Sets a callback that is called with an array of subscriptions to be added