Merge pull request #682 from github-for-unity/fixes/infinite-loop-on-cache-update

Fix an infinite cache invalidation loop

Author: StanleyGoldman

src/UnityExtension/Assets/Editor/GitHub.Unity/ApplicationCache.cs

@@ -136,6 +136,7 @@ abstract class ManagedCacheBase<T> : ScriptObjectSingleton<T> where T : Scriptab
         [SerializeField] private string initializedAtString = DateTimeOffset.MinValue.ToString(Constants.Iso8601Format);
         [NonSerialized] private DateTimeOffset? lastUpdatedAtValue;
         [NonSerialized] private DateTimeOffset? initializedAtValue;
+        [NonSerialized] private bool isInvalidating;
 
         public event Action<CacheType> CacheInvalidated;
         public event Action<CacheType, DateTimeOffset> CacheUpdated;
@@ -151,7 +152,7 @@ public bool ValidateData()
             var isInitialized = IsInitialized;
             var timedOut = DateTimeOffset.Now - LastUpdatedAt > DataTimeout;
             var needsInvalidation = !isInitialized || timedOut;
-            if (needsInvalidation)
+            if (needsInvalidation && !isInvalidating)
             {
                 Logger.Trace("needsInvalidation isInitialized:{0} timedOut:{1}", isInitialized, timedOut);
                 InvalidateData();
@@ -161,21 +162,27 @@ public bool ValidateData()
 
         public void InvalidateData()
         {
-            Logger.Trace("Invalidate");
-            LastUpdatedAt = DateTimeOffset.MinValue;
-            CacheInvalidated.SafeInvoke(CacheType);
+            if (!isInvalidating)
+            {
+                Logger.Trace("Invalidate");
+                isInvalidating = true;
+                LastUpdatedAt = DateTimeOffset.MinValue;
+                CacheInvalidated.SafeInvoke(CacheType);
+            }
         }
 
         protected void SaveData(DateTimeOffset now, bool isChanged)
         {
             var isInitialized = IsInitialized;
             isChanged = isChanged || !isInitialized;
 
-            InitializedAt = !isInitialized ? now : InitializedAt;
-            LastUpdatedAt = isChanged ? now : LastUpdatedAt;
+            InitializedAt = !isInitialized || InitializedAt == DateTimeOffset.MinValue ? now : InitializedAt;
+            LastUpdatedAt = isChanged || LastUpdatedAt == DateTimeOffset.MinValue ? now : LastUpdatedAt;
 
             Save(true);
 
+            isInvalidating = false;
+
             if (isChanged)
             {
                 Logger.Trace("Updated: {0}", now);

src/tests/IntegrationTests/CachingClasses.cs

@@ -124,7 +124,7 @@ public bool ValidateData()
             var isInitialized = IsInitialized;
             var timedOut = DateTimeOffset.Now - LastUpdatedAt > DataTimeout;
             var needsInvalidation = !isInitialized || timedOut;
-            if (needsInvalidation)
+            if (needsInvalidation && !isInvalidating)
             {
                 Logger.Trace("needsInvalidation isInitialized:{0} timedOut:{1}", isInitialized, timedOut);
                 InvalidateData();
@@ -134,9 +134,9 @@ public bool ValidateData()
 
         public void InvalidateData()
         {
-            Logger.Trace("Invalidate");
             if (!isInvalidating)
             {
+                Logger.Trace("Invalidate");
                 isInvalidating = true;
                 LastUpdatedAt = DateTimeOffset.MinValue;
                 CacheInvalidated.SafeInvoke(CacheType);
@@ -148,8 +148,8 @@ protected void SaveData(DateTimeOffset now, bool isChanged)
             var isInitialized = IsInitialized;
             isChanged = isChanged || !isInitialized;
 
-            InitializedAt = !isInitialized ? now : InitializedAt;
-            LastUpdatedAt = isChanged ? now : LastUpdatedAt;
+            InitializedAt = !isInitialized || InitializedAt == DateTimeOffset.MinValue ? now : InitializedAt;
+            LastUpdatedAt = isChanged || LastUpdatedAt == DateTimeOffset.MinValue ? now : LastUpdatedAt;
 
             Save(true);