From ac16e66325570ce926a3485cce793037c09f7e20 Mon Sep 17 00:00:00 2001
From: Andreia Gaita <shana@spoiledcat.net>
Date: Thu, 1 Feb 2018 16:19:52 +0100
Subject: [PATCH] Make sure we always create a valid index if the database has
 old/invalid json data

Fixes #1319
---
 src/GitHub.App/Caches/CacheIndex.cs             | 1 +
 src/GitHub.App/Extensions/AkavacheExtensions.cs | 7 ++++++-
 2 files changed, 7 insertions(+), 1 deletion(-)

diff --git a/src/GitHub.App/Caches/CacheIndex.cs b/src/GitHub.App/Caches/CacheIndex.cs
index a3eca8a0e8..d3ad77de7f 100644
--- a/src/GitHub.App/Caches/CacheIndex.cs
+++ b/src/GitHub.App/Caches/CacheIndex.cs
@@ -62,6 +62,7 @@ public static IObservable<CacheIndex> AddAndSaveToIndex(IBlobCache cache, string
             Guard.ArgumentNotNull(item, nameof(item));
 
             return cache.GetOrCreateObject(indexKey, () => Create(indexKey))
+                .Select(x => x.IndexKey == null ? Create(indexKey) : x)
                 .Do(index =>
                 {
                     var k = string.Format(CultureInfo.InvariantCulture, "{0}|{1}", index.IndexKey, item.Key);
diff --git a/src/GitHub.App/Extensions/AkavacheExtensions.cs b/src/GitHub.App/Extensions/AkavacheExtensions.cs
index a95e4c5c8d..bbf59bed19 100644
--- a/src/GitHub.App/Extensions/AkavacheExtensions.cs
+++ b/src/GitHub.App/Extensions/AkavacheExtensions.cs
@@ -200,7 +200,11 @@ static IObservable<T> GetAndFetchLatestFromIndex<T>(this IBlobCache This,
             bool shouldInvalidateOnError = false)
                 where T : CacheItem
         {
-            var idx = Observable.Defer(() => This.GetOrCreateObject(key, () => CacheIndex.Create(key))).Replay().RefCount();
+            var idx = Observable.Defer(() => This
+                                            .GetOrCreateObject(key, () => CacheIndex.Create(key)))
+                                            .Select(x => x.IndexKey == null ? CacheIndex.Create(key) : x)
+                                            .Replay()
+                                            .RefCount();
 
 
             var fetch = idx
@@ -264,6 +268,7 @@ public static IObservable<T> PutAndUpdateIndex<T>(this IBlobCache blobCache,
             {
                 var absoluteExpiration = blobCache.Scheduler.Now + maxCacheDuration;
                 return blobCache.GetOrCreateObject(key, () => CacheIndex.Create(key))
+                    .Select(x => x.IndexKey == null ? CacheIndex.Create(key) : x)
                     .SelectMany(index => fetchFunc()
                             .Catch<T, Exception>(Observable.Throw<T>)
                             .SelectMany(x => x.Save<T>(blobCache, key, absoluteExpiration))