Fixed: Don't retry grabbing the same release if download client is unavailable

Closes #3116

src/NzbDrone.Core.Test/Download/DownloadServiceFixture.cs

@@ -32,7 +32,7 @@ namespace NzbDrone.Core.Test.Download
                 .Returns(_downloadClients);
 
             Mocker.GetMock<IProvideDownloadClient>()
-                .Setup(v => v.GetDownloadClient(It.IsAny<DownloadProtocol>(), It.IsAny<int>()))
+                .Setup(v => v.GetDownloadClient(It.IsAny<DownloadProtocol>(), It.IsAny<int>(), It.IsAny<bool>()))
                 .Returns<DownloadProtocol, int>((v, i) => _downloadClients.FirstOrDefault(d => d.Protocol == v));
 
             var episodes = Builder<Episode>.CreateListOfSize(2)

src/NzbDrone.Core/Download/DownloadClientProvider.cs

@@ -9,7 +9,7 @@ namespace NzbDrone.Core.Download
 {
     public interface IProvideDownloadClient
     {
-        IDownloadClient GetDownloadClient(DownloadProtocol downloadProtocol, int indexerId = 0);
+        IDownloadClient GetDownloadClient(DownloadProtocol downloadProtocol, int indexerId = 0, bool filterBlockedClients = false);
         IEnumerable<IDownloadClient> GetDownloadClients(bool filterBlockedClients = false);
         IDownloadClient Get(int id);
     }
@@ -35,8 +35,9 @@ namespace NzbDrone.Core.Download
             _lastUsedDownloadClient = cacheManager.GetCache<int>(GetType(), "lastDownloadClientId");
         }
 
-        public IDownloadClient GetDownloadClient(DownloadProtocol downloadProtocol, int indexerId = 0)
+        public IDownloadClient GetDownloadClient(DownloadProtocol downloadProtocol, int indexerId = 0, bool filterBlockedClients = false)
         {
+            var blockedProviders = new HashSet<int>(_downloadClientStatusService.GetBlockedProviders().Select(v => v.ProviderId));
             var availableProviders = _downloadClientFactory.GetAvailableProviders().Where(v => v.Protocol == downloadProtocol).ToList();
 
             if (!availableProviders.Any())
@@ -52,11 +53,14 @@ namespace NzbDrone.Core.Download
                 {
                     var client = availableProviders.SingleOrDefault(d => d.Definition.Id == indexer.DownloadClientId);
 
-                    return client ?? throw new DownloadClientUnavailableException($"Indexer specified download client is not available");
-                }
+                    if (client == null || (filterBlockedClients && blockedProviders.Contains(client.Definition.Id)))
+                    {
+                        throw new DownloadClientUnavailableException($"Indexer specified download client is not available");
                     }
 
-            var blockedProviders = new HashSet<int>(_downloadClientStatusService.GetBlockedProviders().Select(v => v.ProviderId));
+                    return client;
+                }
+            }
 
             if (blockedProviders.Any())
             {
@@ -66,6 +70,10 @@ namespace NzbDrone.Core.Download
                 {
                     availableProviders = nonBlockedProviders;
                 }
+                else if (filterBlockedClients)
+                {
+                    throw new DownloadClientUnavailableException($"All download clients for {downloadProtocol} are not available");
+                }
                 else
                 {
                     _logger.Trace("No non-blocked Download Client available, retrying blocked one.");

src/NzbDrone.Core/Download/DownloadService.cs

@@ -6,6 +6,7 @@ using NzbDrone.Common.Http;
 using NzbDrone.Common.Instrumentation.Extensions;
 using NzbDrone.Common.TPL;
 using NzbDrone.Core.Download.Clients;
+using NzbDrone.Core.Download.Pending;
 using NzbDrone.Core.Exceptions;
 using NzbDrone.Core.Indexers;
 using NzbDrone.Core.Messaging.Events;
@@ -50,9 +51,11 @@ namespace NzbDrone.Core.Download
 
         public void DownloadReport(RemoteEpisode remoteEpisode, int? downloadClientId)
         {
+            var filterBlockedClients = remoteEpisode.Release.PendingReleaseReason == PendingReleaseReason.DownloadClientUnavailable;
+
             var downloadClient = downloadClientId.HasValue
                 ? _downloadClientProvider.Get(downloadClientId.Value)
-                : _downloadClientProvider.GetDownloadClient(remoteEpisode.Release.DownloadProtocol, remoteEpisode.Release.IndexerId);
+                : _downloadClientProvider.GetDownloadClient(remoteEpisode.Release.DownloadProtocol, remoteEpisode.Release.IndexerId, filterBlockedClients);
 
             DownloadReport(remoteEpisode, downloadClient);
         }

src/NzbDrone.Core/Download/Pending/PendingReleaseService.cs

@@ -139,7 +139,14 @@ namespace NzbDrone.Core.Download.Pending
 
         public List<ReleaseInfo> GetPending()
         {
-            var releases = _repository.All().Select(p => p.Release).ToList();
+            var releases = _repository.All().Select(p =>
+            {
+                var release = p.Release;
+
+                release.PendingReleaseReason = p.Reason;
+
+                return release;
+            }).ToList();
 
             if (releases.Any())
             {

src/NzbDrone.Core/Parser/Model/ReleaseInfo.cs

@@ -1,6 +1,8 @@
 using System;
 using System.Collections.Generic;
 using System.Text;
+using Newtonsoft.Json;
+using NzbDrone.Core.Download.Pending;
 using NzbDrone.Core.Indexers;
 using NzbDrone.Core.Languages;
 
@@ -37,6 +39,10 @@ namespace NzbDrone.Core.Parser.Model
 
         public List<Language> Languages { get; set; }
 
+        // Used to track pending releases that are being reprocessed
+        [JsonIgnore]
+        public PendingReleaseReason? PendingReleaseReason { get; set; }
+
         public int Age
         {
             get