Fixed: Don't delete tags used by indexer proxies

src/NzbDrone.Core.Test/Housekeeping/Housekeepers/CleanupUnusedTagsFixture.cs

@@ -2,6 +2,8 @@ using FizzWare.NBuilder;
 using FluentAssertions;
 using NUnit.Framework;
 using NzbDrone.Core.Housekeeping.Housekeepers;
+using NzbDrone.Core.IndexerProxies;
+using NzbDrone.Core.IndexerProxies.Http;
 using NzbDrone.Core.Tags;
 using NzbDrone.Core.Test.Framework;
 
@@ -22,5 +24,30 @@ namespace NzbDrone.Core.Test.Housekeeping.Housekeepers
             Subject.Clean();
             AllStoredModels.Should().BeEmpty();
         }
+
+        [Test]
+        public void should_not_delete_used_tags()
+        {
+            var tags = Builder<Tag>
+                .CreateListOfSize(2)
+                .All()
+                .With(x => x.Id = 0)
+                .BuildList();
+
+            Db.InsertMany(tags);
+
+            var settings = Builder<HttpSettings>.CreateNew().Build();
+
+            var restrictions = Builder<IndexerProxyDefinition>.CreateListOfSize(2)
+                .All()
+                .With(x => x.Id = 0)
+                .With(x => x.Settings = settings)
+                .With(v => v.Tags.Add(tags[0].Id))
+                .BuildList();
+            Db.InsertMany(restrictions);
+
+            Subject.Clean();
+            AllStoredModels.Should().HaveCount(1);
+        }
     }
 }

src/NzbDrone.Core/Housekeeping/Housekeepers/CleanupUnusedTags.cs

@@ -19,7 +19,7 @@ namespace NzbDrone.Core.Housekeeping.Housekeepers
         {
             using (var mapper = _database.OpenConnection())
             {
-                var usedTags = new[] { "Notifications" }
+                var usedTags = new[] { "Notifications", "IndexerProxies", "Indexers", "Applications" }
                     .SelectMany(v => GetUsedTags(v, mapper))
                     .Distinct()
                     .ToArray();