Avoid unnecessary zero-length array allocations

.editorconfig

@@ -194,7 +194,6 @@ dotnet_diagnostic.CA1819.severity = suggestion
 dotnet_diagnostic.CA1822.severity = suggestion
 dotnet_diagnostic.CA1823.severity = suggestion
 dotnet_diagnostic.CA1824.severity = suggestion
-dotnet_diagnostic.CA1825.severity = suggestion
 dotnet_diagnostic.CA1826.severity = suggestion
 dotnet_diagnostic.CA1827.severity = suggestion
 dotnet_diagnostic.CA1829.severity = suggestion

src/NzbDrone.Common.Test/EnvironmentTests/StartupArgumentsFixture.cs

@@ -1,3 +1,4 @@
+using System;
 using FluentAssertions;
 using NUnit.Framework;
 using NzbDrone.Common.EnvironmentInfo;
@@ -11,7 +12,7 @@ namespace NzbDrone.Common.Test.EnvironmentTests
         [Test]
         public void empty_array_should_return_empty_flags()
         {
-            var args = new StartupContext(new string[0]);
+            var args = new StartupContext(Array.Empty<string>());
             args.Flags.Should().BeEmpty();
         }
 

src/NzbDrone.Common.Test/Http/HttpClientFixture.cs

@@ -102,7 +102,7 @@ namespace NzbDrone.Common.Test.Http
             Mocker.SetConstant<ICertificateValidationService>(new X509CertificateValidationService(Mocker.GetMock<IConfigService>().Object, TestLogger));
 
             Mocker.SetConstant<IRateLimitService>(Mocker.Resolve<RateLimitService>());
-            Mocker.SetConstant<IEnumerable<IHttpRequestInterceptor>>(new IHttpRequestInterceptor[0]);
+            Mocker.SetConstant<IEnumerable<IHttpRequestInterceptor>>(Array.Empty<IHttpRequestInterceptor>());
             Mocker.SetConstant<IHttpDispatcher>(Mocker.Resolve<TDispatcher>());
 
             // Used for manual testing of socks proxies.
@@ -459,7 +459,7 @@ namespace NzbDrone.Common.Test.Http
             var oldRequest = new HttpRequest($"https://{_httpBinHost2}/get");
             oldRequest.Cookies["my"] = "cookie";
 
-            var oldClient = new HttpClient(new IHttpRequestInterceptor[0], Mocker.Resolve<ICacheManager>(), Mocker.Resolve<IRateLimitService>(), Mocker.Resolve<IHttpDispatcher>(), Mocker.GetMock<IUserAgentBuilder>().Object, Mocker.Resolve<Logger>());
+            var oldClient = new HttpClient(Array.Empty<IHttpRequestInterceptor>(), Mocker.Resolve<ICacheManager>(), Mocker.Resolve<IRateLimitService>(), Mocker.Resolve<IHttpDispatcher>(), Mocker.GetMock<IUserAgentBuilder>().Object, Mocker.Resolve<Logger>());
 
             oldClient.Should().NotBeSameAs(Subject);
 

src/NzbDrone.Common/Http/HttpResponse.cs

@@ -60,7 +60,7 @@ namespace NzbDrone.Common.Http
 
         public string[] GetCookieHeaders()
         {
-            return Headers.GetValues("Set-Cookie") ?? new string[0];
+            return Headers.GetValues("Set-Cookie") ?? Array.Empty<string>();
         }
 
         public Dictionary<string, string> GetCookies()

src/NzbDrone.Core.Test/Download/DownloadClientTests/DelugeTests/DelugeFixture.cs

@@ -89,7 +89,7 @@ namespace NzbDrone.Core.Test.Download.DownloadClientTests.DelugeTests
 
             Mocker.GetMock<IHttpClient>()
                   .Setup(s => s.Get(It.IsAny<HttpRequest>()))
-                  .Returns<HttpRequest>(r => new HttpResponse(r, new HttpHeader(), new byte[0]));
+                  .Returns<HttpRequest>(r => new HttpResponse(r, new HttpHeader(), Array.Empty<byte>()));
         }
 
         protected void GivenFailedDownload()

src/NzbDrone.Core.Test/Download/DownloadClientTests/DownloadClientFixtureBase.cs

@@ -35,7 +35,7 @@ namespace NzbDrone.Core.Test.Download.DownloadClientTests
 
             Mocker.GetMock<IHttpClient>()
                   .Setup(s => s.Get(It.IsAny<HttpRequest>()))
-                  .Returns<HttpRequest>(r => new HttpResponse(r, new HttpHeader(), new byte[0]));
+                  .Returns<HttpRequest>(r => new HttpResponse(r, new HttpHeader(), Array.Empty<byte>()));
 
             Mocker.GetMock<IRemotePathMappingService>()
                 .Setup(v => v.RemapRemoteToLocal(It.IsAny<string>(), It.IsAny<OsPath>()))

src/NzbDrone.Core.Test/Download/DownloadClientTests/DownloadStationTests/TorrentDownloadStationFixture.cs

@@ -277,7 +277,7 @@ namespace NzbDrone.Core.Test.Download.DownloadClientTests.DownloadStationTests
 
             Mocker.GetMock<IHttpClient>()
                   .Setup(s => s.Get(It.IsAny<HttpRequest>()))
-                  .Returns<HttpRequest>(r => new HttpResponse(r, new HttpHeader(), new byte[0]));
+                  .Returns<HttpRequest>(r => new HttpResponse(r, new HttpHeader(), Array.Empty<byte>()));
 
             _downloadStationConfigItems = new Dictionary<string, object>
             {

src/NzbDrone.Core.Test/Download/DownloadClientTests/DownloadStationTests/UsenetDownloadStationFixture.cs

@@ -170,7 +170,7 @@ namespace NzbDrone.Core.Test.Download.DownloadClientTests.DownloadStationTests
 
             Mocker.GetMock<IHttpClient>()
                   .Setup(s => s.Get(It.IsAny<HttpRequest>()))
-                  .Returns<HttpRequest>(r => new HttpResponse(r, new HttpHeader(), new byte[0]));
+                  .Returns<HttpRequest>(r => new HttpResponse(r, new HttpHeader(), Array.Empty<byte>()));
 
             _downloadStationConfigItems = new Dictionary<string, object>
             {

src/NzbDrone.Core.Test/Download/DownloadClientTests/FreeboxDownloadTests/TorrentFreeboxDownloadFixture.cs

@@ -79,7 +79,7 @@ namespace NzbDrone.Core.Test.Download.DownloadClientTests.FreeboxDownloadTests
 
             Mocker.GetMock<IHttpClient>()
                   .Setup(s => s.Get(It.IsAny<HttpRequest>()))
-                  .Returns<HttpRequest>(r => new HttpResponse(r, new HttpHeader(), new byte[0]));
+                  .Returns<HttpRequest>(r => new HttpResponse(r, new HttpHeader(), Array.Empty<byte>()));
         }
 
         protected void GivenCategory()

src/NzbDrone.Core.Test/Download/DownloadClientTests/HadoukenTests/HadoukenFixture.cs

@@ -86,7 +86,7 @@ namespace NzbDrone.Core.Test.Download.DownloadClientTests.HadoukenTests
 
             Mocker.GetMock<IHttpClient>()
                   .Setup(s => s.Get(It.IsAny<HttpRequest>()))
-                  .Returns<HttpRequest>(r => new HttpResponse(r, new HttpHeader(), new byte[0]));
+                  .Returns<HttpRequest>(r => new HttpResponse(r, new HttpHeader(), Array.Empty<byte>()));
         }
 
         protected void GivenFailedDownload()

src/NzbDrone.Core.Test/Download/DownloadClientTests/QBittorrentTests/QBittorrentFixture.cs

@@ -38,7 +38,7 @@ namespace NzbDrone.Core.Test.Download.DownloadClientTests.QBittorrentTests
 
             Mocker.GetMock<IHttpClient>()
                   .Setup(s => s.Get(It.IsAny<HttpRequest>()))
-                  .Returns<HttpRequest>(r => new HttpResponse(r, new HttpHeader(), new byte[0]));
+                  .Returns<HttpRequest>(r => new HttpResponse(r, new HttpHeader(), Array.Empty<byte>()));
 
             Mocker.GetMock<IQBittorrentProxy>()
                   .Setup(s => s.GetConfig(It.IsAny<QBittorrentSettings>()))
@@ -56,7 +56,7 @@ namespace NzbDrone.Core.Test.Download.DownloadClientTests.QBittorrentTests
 
             Mocker.GetMock<IHttpClient>()
                   .Setup(s => s.Get(It.IsAny<HttpRequest>()))
-                  .Returns<HttpRequest>(r => new HttpResponse(r, httpHeader, new byte[0], System.Net.HttpStatusCode.SeeOther));
+                  .Returns<HttpRequest>(r => new HttpResponse(r, httpHeader, Array.Empty<byte>(), System.Net.HttpStatusCode.SeeOther));
         }
 
         protected void GivenRedirectToTorrent()
@@ -66,7 +66,7 @@ namespace NzbDrone.Core.Test.Download.DownloadClientTests.QBittorrentTests
 
             Mocker.GetMock<IHttpClient>()
                   .Setup(s => s.Get(It.Is<HttpRequest>(h => h.Url.FullUri == _downloadUrl)))
-                  .Returns<HttpRequest>(r => new HttpResponse(r, httpHeader, new byte[0], System.Net.HttpStatusCode.Found));
+                  .Returns<HttpRequest>(r => new HttpResponse(r, httpHeader, Array.Empty<byte>(), System.Net.HttpStatusCode.Found));
         }
 
         protected void GivenFailedDownload()
@@ -523,7 +523,7 @@ namespace NzbDrone.Core.Test.Download.DownloadClientTests.QBittorrentTests
 
             Mocker.GetMock<IQBittorrentProxy>()
                   .Setup(v => v.MoveTorrentToTopInQueue(It.IsAny<string>(), It.IsAny<QBittorrentSettings>()))
-                  .Throws(new HttpException(new HttpResponse(new HttpRequest("http://me.local/"), new HttpHeader(), new byte[0], System.Net.HttpStatusCode.Forbidden)));
+                  .Throws(new HttpException(new HttpResponse(new HttpRequest("http://me.local/"), new HttpHeader(), Array.Empty<byte>(), System.Net.HttpStatusCode.Forbidden)));
 
             var remoteEpisode = CreateRemoteEpisode();
 

src/NzbDrone.Core.Test/Download/DownloadClientTests/SabnzbdTests/SabnzbdFixture.cs

@@ -545,7 +545,7 @@ namespace NzbDrone.Core.Test.Download.DownloadClientTests.SabnzbdTests
         public void should_test_failed_if_tv_sorting_empty()
         {
             _config.Misc.enable_tv_sorting = true;
-            _config.Misc.tv_categories = new string[0];
+            _config.Misc.tv_categories = Array.Empty<string>();
 
             var result = new NzbDroneValidationResult(Subject.Test());
 

src/NzbDrone.Core.Test/Download/DownloadClientTests/TransmissionTests/TransmissionFixtureBase.cs

@@ -99,7 +99,7 @@ namespace NzbDrone.Core.Test.Download.DownloadClientTests.TransmissionTests
 
             Mocker.GetMock<IHttpClient>()
                   .Setup(s => s.Get(It.IsAny<HttpRequest>()))
-                  .Returns<HttpRequest>(r => new HttpResponse(r, new HttpHeader(), new byte[0]));
+                  .Returns<HttpRequest>(r => new HttpResponse(r, new HttpHeader(), Array.Empty<byte>()));
 
             _transmissionConfigItems = new Dictionary<string, object>();
 

src/NzbDrone.Core.Test/Download/DownloadClientTests/UTorrentTests/UTorrentFixture.cs

@@ -91,7 +91,7 @@ namespace NzbDrone.Core.Test.Download.DownloadClientTests.UTorrentTests
 
             Mocker.GetMock<IHttpClient>()
                   .Setup(s => s.Get(It.IsAny<HttpRequest>()))
-                  .Returns<HttpRequest>(r => new HttpResponse(r, new HttpHeader(), new byte[0]));
+                  .Returns<HttpRequest>(r => new HttpResponse(r, new HttpHeader(), Array.Empty<byte>()));
         }
 
         protected void GivenRedirectToMagnet()
@@ -101,7 +101,7 @@ namespace NzbDrone.Core.Test.Download.DownloadClientTests.UTorrentTests
 
             Mocker.GetMock<IHttpClient>()
                   .Setup(s => s.Get(It.IsAny<HttpRequest>()))
-                  .Returns<HttpRequest>(r => new HttpResponse(r, httpHeader, new byte[0], System.Net.HttpStatusCode.SeeOther));
+                  .Returns<HttpRequest>(r => new HttpResponse(r, httpHeader, Array.Empty<byte>(), System.Net.HttpStatusCode.SeeOther));
         }
 
         protected void GivenRedirectToTorrent()
@@ -111,7 +111,7 @@ namespace NzbDrone.Core.Test.Download.DownloadClientTests.UTorrentTests
 
             Mocker.GetMock<IHttpClient>()
                   .Setup(s => s.Get(It.Is<HttpRequest>(h => h.Url.ToString() == _downloadUrl)))
-                  .Returns<HttpRequest>(r => new HttpResponse(r, httpHeader, new byte[0], System.Net.HttpStatusCode.Found));
+                  .Returns<HttpRequest>(r => new HttpResponse(r, httpHeader, Array.Empty<byte>(), System.Net.HttpStatusCode.Found));
         }
 
         protected void GivenFailedDownload()

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

@@ -132,7 +132,7 @@ namespace NzbDrone.Core.Test.Download
         public void Download_report_should_trigger_indexer_backoff_on_http429_with_long_time()
         {
             var request = new HttpRequest("http://my.indexer.com");
-            var response = new HttpResponse(request, new HttpHeader(), new byte[0], (HttpStatusCode)429);
+            var response = new HttpResponse(request, new HttpHeader(), Array.Empty<byte>(), (HttpStatusCode)429);
             response.Headers["Retry-After"] = "300";
 
             var mock = WithUsenetClient();
@@ -152,7 +152,7 @@ namespace NzbDrone.Core.Test.Download
         public void Download_report_should_trigger_indexer_backoff_on_http429_based_on_date()
         {
             var request = new HttpRequest("http://my.indexer.com");
-            var response = new HttpResponse(request, new HttpHeader(), new byte[0], (HttpStatusCode)429);
+            var response = new HttpResponse(request, new HttpHeader(), Array.Empty<byte>(), (HttpStatusCode)429);
             response.Headers["Retry-After"] = DateTime.UtcNow.AddSeconds(300).ToString("r");
 
             var mock = WithUsenetClient();

src/NzbDrone.Core.Test/Framework/CoreTest.cs

@@ -26,7 +26,7 @@ namespace NzbDrone.Core.Test.Framework
             Mocker.SetConstant<ICreateManagedWebProxy>(new ManagedWebProxyFactory(Mocker.Resolve<CacheManager>()));
             Mocker.SetConstant<ICertificateValidationService>(new X509CertificateValidationService(Mocker.Resolve<ConfigService>(), TestLogger));
             Mocker.SetConstant<IHttpDispatcher>(new ManagedHttpDispatcher(Mocker.Resolve<IHttpProxySettingsProvider>(), Mocker.Resolve<ICreateManagedWebProxy>(), Mocker.Resolve<ICertificateValidationService>(), Mocker.Resolve<UserAgentBuilder>(), Mocker.Resolve<CacheManager>(), TestLogger));
-            Mocker.SetConstant<IHttpClient>(new HttpClient(new IHttpRequestInterceptor[0], Mocker.Resolve<CacheManager>(), Mocker.Resolve<RateLimitService>(), Mocker.Resolve<IHttpDispatcher>(), Mocker.Resolve<UserAgentBuilder>(), TestLogger));
+            Mocker.SetConstant<IHttpClient>(new HttpClient(Array.Empty<IHttpRequestInterceptor>(), Mocker.Resolve<CacheManager>(), Mocker.Resolve<RateLimitService>(), Mocker.Resolve<IHttpDispatcher>(), Mocker.Resolve<UserAgentBuilder>(), TestLogger));
             Mocker.SetConstant<ISonarrCloudRequestBuilder>(new SonarrCloudRequestBuilder());
         }
     }

src/NzbDrone.Core.Test/HealthCheck/Checks/DownloadClientCheckFixture.cs

@@ -16,7 +16,7 @@ namespace NzbDrone.Core.Test.HealthCheck.Checks
         {
             Mocker.GetMock<IProvideDownloadClient>()
                   .Setup(s => s.GetDownloadClients())
-                  .Returns(new IDownloadClient[0]);
+                  .Returns(Array.Empty<IDownloadClient>());
 
             Subject.Check().ShouldBeWarning();
         }

src/NzbDrone.Core.Test/IndexerTests/BroadcastheNetTests/BroadcastheNetFixture.cs

@@ -76,7 +76,7 @@ namespace NzbDrone.Core.Test.IndexerTests.BroadcastheNetTests
         {
             Mocker.GetMock<IHttpClient>()
                 .Setup(v => v.Execute(It.IsAny<HttpRequest>()))
-                .Returns<HttpRequest>(r => new HttpResponse(r, new HttpHeader(), new byte[0], System.Net.HttpStatusCode.BadRequest));
+                .Returns<HttpRequest>(r => new HttpResponse(r, new HttpHeader(), Array.Empty<byte>(), System.Net.HttpStatusCode.BadRequest));
 
             var results = Subject.FetchRecent();
 
@@ -92,7 +92,7 @@ namespace NzbDrone.Core.Test.IndexerTests.BroadcastheNetTests
         {
             Mocker.GetMock<IHttpClient>()
                 .Setup(v => v.Execute(It.IsAny<HttpRequest>()))
-                .Returns<HttpRequest>(r => new HttpResponse(r, new HttpHeader(), new byte[0], System.Net.HttpStatusCode.Unauthorized));
+                .Returns<HttpRequest>(r => new HttpResponse(r, new HttpHeader(), Array.Empty<byte>(), System.Net.HttpStatusCode.Unauthorized));
 
             var results = Subject.FetchRecent();
 
@@ -108,7 +108,7 @@ namespace NzbDrone.Core.Test.IndexerTests.BroadcastheNetTests
         {
             Mocker.GetMock<IHttpClient>()
                 .Setup(v => v.Execute(It.IsAny<HttpRequest>()))
-                .Returns<HttpRequest>(r => new HttpResponse(r, new HttpHeader(), new byte[0], System.Net.HttpStatusCode.NotFound));
+                .Returns<HttpRequest>(r => new HttpResponse(r, new HttpHeader(), Array.Empty<byte>(), System.Net.HttpStatusCode.NotFound));
 
             var results = Subject.FetchRecent();
 
@@ -124,7 +124,7 @@ namespace NzbDrone.Core.Test.IndexerTests.BroadcastheNetTests
         {
             Mocker.GetMock<IHttpClient>()
                 .Setup(v => v.Execute(It.IsAny<HttpRequest>()))
-                .Returns<HttpRequest>(r => new HttpResponse(r, new HttpHeader(), new byte[0], System.Net.HttpStatusCode.ServiceUnavailable));
+                .Returns<HttpRequest>(r => new HttpResponse(r, new HttpHeader(), Array.Empty<byte>(), System.Net.HttpStatusCode.ServiceUnavailable));
 
             var results = Subject.FetchRecent();
 

src/NzbDrone.Core.Test/IndexerTests/NewznabTests/NewznabFixture.cs

@@ -115,7 +115,7 @@ namespace NzbDrone.Core.Test.IndexerTests.NewznabTests
         public void should_record_indexer_failure_if_caps_throw()
         {
             var request = new HttpRequest("http://my.indexer.com");
-            var response = new HttpResponse(request, new HttpHeader(), new byte[0], (HttpStatusCode)429);
+            var response = new HttpResponse(request, new HttpHeader(), Array.Empty<byte>(), (HttpStatusCode)429);
             response.Headers["Retry-After"] = "300";
 
             Mocker.GetMock<INewznabCapabilitiesProvider>()

src/NzbDrone.Core.Test/MediaFiles/DownloadedEpisodesImportServiceFixture.cs

@@ -1,3 +1,4 @@
+using System;
 using System.Collections.Generic;
 using System.IO;
 using System.Linq;
@@ -91,7 +92,7 @@ namespace NzbDrone.Core.Test.MediaFiles
         private void WasImportedResponse()
         {
             Mocker.GetMock<IDiskScanService>().Setup(c => c.GetVideoFiles(It.IsAny<string>(), It.IsAny<bool>()))
-                  .Returns(new string[0]);
+                  .Returns(Array.Empty<string>());
         }
 
         [Test]
@@ -140,7 +141,7 @@ namespace NzbDrone.Core.Test.MediaFiles
 
             Mocker.GetMock<IDiskScanService>()
                   .Setup(c => c.GetVideoFiles(It.IsAny<string>(), It.IsAny<bool>()))
-                  .Returns(new string[0]);
+                  .Returns(Array.Empty<string>());
 
             Subject.ProcessRootFolder(new DirectoryInfo(_droneFactory));
 

src/NzbDrone.Core.Test/MediaFiles/EpisodeImport/Specifications/MatchesFolderSpecificationFixture.cs

@@ -1,3 +1,4 @@
+using System;
 using System.Linq;
 using FizzWare.NBuilder;
 using FluentAssertions;
@@ -84,7 +85,7 @@ namespace NzbDrone.Core.Test.MediaFiles.EpisodeImport.Specifications
         public void should_should_be_accepted_for_full_season()
         {
             _localEpisode.Path = @"C:\Test\Unsorted\Series.Title.S01\S01E01.mkv".AsOsAgnostic();
-            _localEpisode.FolderEpisodeInfo.EpisodeNumbers = new int[0];
+            _localEpisode.FolderEpisodeInfo.EpisodeNumbers = Array.Empty<int>();
             _localEpisode.FolderEpisodeInfo.FullSeason = true;
 
             GivenEpisodes(_localEpisode.FileEpisodeInfo, _localEpisode.FileEpisodeInfo.EpisodeNumbers);

src/NzbDrone.Core.Test/NotificationTests/EmailTests/EmailSettingsValidatorFixture.cs

@@ -1,3 +1,4 @@
+using System;
 using FizzWare.NBuilder;
 using FluentAssertions;
 using NUnit.Framework;
@@ -104,9 +105,9 @@ namespace NzbDrone.Core.Test.NotificationTests.EmailTests
         [Test]
         public void should_not_be_valid_if_to_bcc_cc_are_all_empty()
         {
-            _emailSettings.To = new string[] { };
-            _emailSettings.Cc = new string[] { };
-            _emailSettings.Bcc = new string[] { };
+            _emailSettings.To = Array.Empty<string>();
+            _emailSettings.Cc = Array.Empty<string>();
+            _emailSettings.Bcc = Array.Empty<string>();
 
             _validator.Validate(_emailSettings).IsValid.Should().BeFalse();
         }

src/NzbDrone.Core.Test/ParserTests/ParsingServiceTests/GetEpisodesFixture.cs

@@ -42,7 +42,7 @@ namespace NzbDrone.Core.Test.ParserTests.ParsingServiceTests
                 SeriesTitle = _series.Title,
                 SeasonNumber = 1,
                 EpisodeNumbers = new[] { 1 },
-                AbsoluteEpisodeNumbers = new int[0],
+                AbsoluteEpisodeNumbers = Array.Empty<int>(),
                 Languages = new List<Language> { Language.English }
             };
 
@@ -282,7 +282,7 @@ namespace NzbDrone.Core.Test.ParserTests.ParsingServiceTests
         {
             GivenAbsoluteNumberingSeries();
             _parsedEpisodeInfo.SeasonNumber = seasonNumber;
-            _parsedEpisodeInfo.EpisodeNumbers = new int[] { };
+            _parsedEpisodeInfo.EpisodeNumbers = Array.Empty<int>();
 
             Mocker.GetMock<IEpisodeService>()
                   .Setup(s => s.FindEpisodesBySceneNumbering(It.IsAny<int>(), seasonNumber, It.IsAny<int>()))
@@ -303,7 +303,7 @@ namespace NzbDrone.Core.Test.ParserTests.ParsingServiceTests
         {
             GivenAbsoluteNumberingSeries();
             _parsedEpisodeInfo.SeasonNumber = seasonNumber;
-            _parsedEpisodeInfo.EpisodeNumbers = new int[] { };
+            _parsedEpisodeInfo.EpisodeNumbers = Array.Empty<int>();
 
             Mocker.GetMock<IEpisodeService>()
                   .Setup(s => s.FindEpisodesBySceneNumbering(It.IsAny<int>(), seasonNumber, It.IsAny<int>()))

src/NzbDrone.Core/DecisionEngine/DownloadDecisionMaker.cs

@@ -192,7 +192,7 @@ namespace NzbDrone.Core.DecisionEngine
 
         private DownloadDecision GetDecisionForReport(RemoteEpisode remoteEpisode, SearchCriteriaBase searchCriteria = null)
         {
-            var reasons = new Rejection[0];
+            var reasons = Array.Empty<Rejection>();
 
             foreach (var specifications in _specifications.GroupBy(v => v.Priority).OrderBy(v => v.Key))
             {

src/NzbDrone.Core/Download/Clients/Deluge/DelugeProxy.cs

@@ -354,7 +354,7 @@ namespace NzbDrone.Core.Download.Clients.Deluge
         {
             if (result.Torrents == null)
             {
-                return new DelugeTorrent[0];
+                return Array.Empty<DelugeTorrent>();
             }
 
             return result.Torrents.Values.ToArray();

src/NzbDrone.Core/Download/Clients/Hadouken/HadoukenProxy.cs

@@ -112,7 +112,7 @@ namespace NzbDrone.Core.Download.Clients.Hadouken
         {
             if (torrentsRaw == null)
             {
-                return new HadoukenTorrent[0];
+                return Array.Empty<HadoukenTorrent>();
             }
 
             var torrents = new List<HadoukenTorrent>();

src/NzbDrone.Core/Download/TrackedDownloads/TrackedDownload.cs

@@ -1,4 +1,5 @@
-using NzbDrone.Core.Indexers;
+using System;
+using NzbDrone.Core.Indexers;
 using NzbDrone.Core.Parser.Model;
 
 namespace NzbDrone.Core.Download.TrackedDownloads
@@ -18,7 +19,7 @@ namespace NzbDrone.Core.Download.TrackedDownloads
 
         public TrackedDownload()
         {
-            StatusMessages = new TrackedDownloadStatusMessage[] { };
+            StatusMessages = Array.Empty<TrackedDownloadStatusMessage>();
         }
 
         public void Warn(string message, params object[] args)

src/NzbDrone.Core/ImportLists/Sonarr/SonarrSettings.cs

@@ -1,3 +1,4 @@
+using System;
 using System.Collections.Generic;
 using FluentValidation;
 using NzbDrone.Core.Annotations;
@@ -22,9 +23,9 @@ namespace NzbDrone.Core.ImportLists.Sonarr
         {
             BaseUrl = "";
             ApiKey = "";
-            ProfileIds = new int[] { };
-            LanguageProfileIds = new int[] { };
-            TagIds = new int[] { };
+            ProfileIds = Array.Empty<int>();
+            LanguageProfileIds = Array.Empty<int>();
+            TagIds = Array.Empty<int>();
         }
 
         [FieldDefinition(0, Label = "Full URL", HelpText = "URL, including port, of the Sonarr V3 instance to import from")]

src/NzbDrone.Core/Indexers/FileList/FileListSettings.cs

@@ -1,4 +1,5 @@
-using System.Collections.Concurrent;
+using System;
+using System.Collections.Concurrent;
 using System.Collections.Generic;
 using System.ComponentModel.DataAnnotations;
 using FluentValidation;
@@ -36,7 +37,7 @@ namespace NzbDrone.Core.Indexers.FileList
                 (int)FileListCategories.TV_4K
             };
 
-            AnimeCategories = new int[0];
+            AnimeCategories = Array.Empty<int>();
         }
 
         [FieldDefinition(0, Label = "Username", Privacy = PrivacyLevel.UserName)]

src/NzbDrone.Core/Indexers/Newznab/Newznab.cs

@@ -51,7 +51,7 @@ namespace NzbDrone.Core.Indexers.Newznab
                 yield return GetDefinition("OZnzb.com", GetSettings("https://api.oznzb.com"));
                 yield return GetDefinition("SimplyNZBs", GetSettings("https://simplynzbs.com"));
                 yield return GetDefinition("Tabula Rasa", GetSettings("https://www.tabula-rasa.pw", apiPath: @"/api/v1/api"));
-                yield return GetDefinition("AnimeTosho Usenet", GetSettings("https://feed.animetosho.org", apiPath: @"/nabapi", categories: new int[0], animeCategories: new[] { 5070 }));
+                yield return GetDefinition("AnimeTosho Usenet", GetSettings("https://feed.animetosho.org", apiPath: @"/nabapi", categories: Array.Empty<int>(), animeCategories: new[] { 5070 }));
             }
         }
 

src/NzbDrone.Core/Indexers/Torznab/Torznab.cs

@@ -41,8 +41,8 @@ namespace NzbDrone.Core.Indexers.Torznab
             get
             {
                 yield return GetDefinition("HD4Free.xyz", GetSettings("http://hd4free.xyz"));
-                yield return GetDefinition("AnimeTosho Torrents", GetSettings("https://feed.animetosho.org", apiPath: @"/nabapi", categories: new int[0], animeCategories: new[] { 5070 }));
-                yield return GetDefinition("Nyaa Pantsu", GetSettings("https://nyaa.pantsu.cat", apiPath: @"/feed/torznab", categories: new int[0], animeCategories: new[] { 5070 }));
+                yield return GetDefinition("AnimeTosho Torrents", GetSettings("https://feed.animetosho.org", apiPath: @"/nabapi", categories: Array.Empty<int>(), animeCategories: new[] { 5070 }));
+                yield return GetDefinition("Nyaa Pantsu", GetSettings("https://nyaa.pantsu.cat", apiPath: @"/feed/torznab", categories: Array.Empty<int>(), animeCategories: new[] { 5070 }));
             }
         }
 

src/NzbDrone.Core/Notifications/Mailgun/MailgunSettings.cs

@@ -1,3 +1,4 @@
+using System;
 using System.Collections.Generic;
 using FluentValidation;
 using NzbDrone.Core.Annotations;
@@ -22,7 +23,7 @@ namespace NzbDrone.Core.Notifications.Mailgun
 
       public MailgunSettings()
       {
-          Recipients = new string[] { };
+          Recipients = Array.Empty<string>();
       }
 
       [FieldDefinition(0, Label = "API Key", HelpText = "The API key generated from MailGun")]

src/NzbDrone.Core/Notifications/PushBullet/PushBulletSettings.cs

@@ -1,3 +1,4 @@
+using System;
 using System.Collections.Generic;
 using FluentValidation;
 using NzbDrone.Core.Annotations;
@@ -20,8 +21,8 @@ namespace NzbDrone.Core.Notifications.PushBullet
 
         public PushBulletSettings()
         {
-            DeviceIds = new string[] { };
-            ChannelTags = new string[] { };
+            DeviceIds = Array.Empty<string>();
+            ChannelTags = Array.Empty<string>();
         }
 
         [FieldDefinition(0, Label = "Access Token", Privacy = PrivacyLevel.ApiKey, HelpLink = "https://www.pushbullet.com/#settings/account")]

src/NzbDrone.Core/Notifications/Pushover/PushoverSettings.cs

@@ -1,3 +1,4 @@
+using System;
 using System.Collections.Generic;
 using FluentValidation;
 using NzbDrone.Core.Annotations;
@@ -23,7 +24,7 @@ namespace NzbDrone.Core.Notifications.Pushover
         public PushoverSettings()
         {
             Priority = 0;
-            Devices = new string[] { };
+            Devices = Array.Empty<string>();
         }
 
         // TODO: Get Pushover to change our app name (or create a new app) when we have a new logo

src/NzbDrone.Core/Notifications/SendGrid/SendGridSettings.cs

@@ -1,4 +1,5 @@
-using System.Collections.Generic;
+using System;
+using System.Collections.Generic;
 using FluentValidation;
 using NzbDrone.Core.Annotations;
 using NzbDrone.Core.ThingiProvider;
@@ -24,7 +25,7 @@ namespace NzbDrone.Core.Notifications.SendGrid
         public SendGridSettings()
         {
             BaseUrl = "https://api.sendgrid.com/v3/";
-            Recipients = new string[] { };
+            Recipients = Array.Empty<string>();
         }
 
         public string BaseUrl { get; set; }

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

@@ -1,3 +1,4 @@
+using System;
 using System.Collections.Generic;
 using System.Linq;
 using System.Text.Json.Serialization;
@@ -32,9 +33,9 @@ namespace NzbDrone.Core.Parser.Model
 
         public ParsedEpisodeInfo()
         {
-            EpisodeNumbers = new int[0];
-            AbsoluteEpisodeNumbers = new int[0];
-            SpecialAbsoluteEpisodeNumbers = new decimal[0];
+            EpisodeNumbers = Array.Empty<int>();
+            AbsoluteEpisodeNumbers = Array.Empty<int>();
+            SpecialAbsoluteEpisodeNumbers = Array.Empty<decimal>();
             Languages = new List<Language>();
         }
 

src/NzbDrone.Core/Parser/Parser.cs

@@ -890,8 +890,8 @@ namespace NzbDrone.Core.Parser
                 result = new ParsedEpisodeInfo
                 {
                     ReleaseTitle = releaseTitle,
-                    EpisodeNumbers = new int[0],
-                    AbsoluteEpisodeNumbers = new int[0]
+                    EpisodeNumbers = Array.Empty<int>(),
+                    AbsoluteEpisodeNumbers = Array.Empty<int>()
                 };
 
                 foreach (Match matchGroup in matchCollection)

src/NzbDrone.Host/Startup.cs

@@ -126,7 +126,7 @@ namespace NzbDrone.Host
 
                 c.AddSecurityRequirement(new OpenApiSecurityRequirement
                 {
-                    { apiKeyHeader, new string[] { } }
+                    { apiKeyHeader, Array.Empty<string>() }
                 });
 
                 var apikeyQuery = new OpenApiSecurityScheme
@@ -157,7 +157,7 @@ namespace NzbDrone.Host
 
                 c.AddSecurityRequirement(new OpenApiSecurityRequirement
                 {
-                    { apikeyQuery, new string[] { } }
+                    { apikeyQuery, Array.Empty<string>() }
                 });
             });
 

src/Sonarr.RuntimePatches/Mono/BoringTLSVerifyFlagsPatch.cs

@@ -49,8 +49,8 @@ namespace NzbDrone.RuntimePatches.Mono
             Instance.DebugOpcodes("Before", codes);
 
             var targetType = method.DeclaringType;
-            var copyMethod = targetType.GetMethod("Copy", new Type[0]);
-            var disposeMethod = targetType.GetMethod("Dispose", new Type[0]);
+            var copyMethod = targetType.GetMethod("Copy", Array.Empty<Type>());
+            var disposeMethod = targetType.GetMethod("Dispose", Array.Empty<Type>());
             var setFlagsMethod = targetType.GetMethod("SetFlags", new[] { typeof(ulong) });
 
             if (patchable && copyMethod != null && disposeMethod != null && setFlagsMethod != null)