Enable all analyzers and enforce code style on build

Fixes #3406
Fixes #3407
Fixes #3408
Fixes #3409
Fixes #3410
Fixes #3411
Fixes #3412
Fixes #3413
Fixes #3414
Fixes #3415
Fixes #3416
Fixes #3417
Fixes #3418
Fixes #3419
Fixes #3420
Fixes #3421
Fixes #3422
Fixes #3423

.editorconfig

@@ -32,6 +32,10 @@ csharp_indent_case_contents_when_block = true
 csharp_indent_switch_labels = true
 csharp_indent_labels = flush_left
 
+dotnet_style_qualification_for_field = false:suggestion
+dotnet_style_qualification_for_property = false:suggestion
+dotnet_style_qualification_for_method = false:suggestion
+dotnet_style_qualification_for_event = false:suggestion
 dotnet_naming_style.instance_field_style.capitalization = camel_case
 dotnet_naming_style.instance_field_style.required_prefix = _
 
@@ -64,6 +68,7 @@ dotnet_diagnostic.SA1406.severity = suggestion
 dotnet_diagnostic.SA1410.severity = suggestion
 dotnet_diagnostic.SA1411.severity = suggestion
 dotnet_diagnostic.SA1413.severity = none
+dotnet_diagnostic.SA1512.severity = none
 dotnet_diagnostic.SA1516.severity = none
 dotnet_diagnostic.SA1600.severity = none
 dotnet_diagnostic.SA1601.severity = none
@@ -162,6 +167,7 @@ dotnet_diagnostic.CA1309.severity = suggestion
 dotnet_diagnostic.CA1310.severity = suggestion
 dotnet_diagnostic.CA1401.severity = suggestion
 dotnet_diagnostic.CA1416.severity = suggestion
+dotnet_diagnostic.CA1419.severity = suggestion
 dotnet_diagnostic.CA1507.severity = suggestion
 dotnet_diagnostic.CA1508.severity = suggestion
 dotnet_diagnostic.CA1707.severity = suggestion
@@ -177,9 +183,6 @@ dotnet_diagnostic.CA1720.severity = suggestion
 dotnet_diagnostic.CA1721.severity = suggestion
 dotnet_diagnostic.CA1724.severity = suggestion
 dotnet_diagnostic.CA1725.severity = suggestion
-dotnet_diagnostic.CA1801.severity = suggestion
-dotnet_diagnostic.CA1802.severity = suggestion
-dotnet_diagnostic.CA1805.severity = suggestion
 dotnet_diagnostic.CA1806.severity = suggestion
 dotnet_diagnostic.CA1810.severity = suggestion
 dotnet_diagnostic.CA1812.severity = suggestion
@@ -188,24 +191,14 @@ dotnet_diagnostic.CA1814.severity = suggestion
 dotnet_diagnostic.CA1815.severity = suggestion
 dotnet_diagnostic.CA1816.severity = suggestion
 dotnet_diagnostic.CA1819.severity = suggestion
-dotnet_diagnostic.CA1820.severity = suggestion
-dotnet_diagnostic.CA1821.severity = suggestion
 dotnet_diagnostic.CA1822.severity = suggestion
 dotnet_diagnostic.CA1823.severity = suggestion
 dotnet_diagnostic.CA1824.severity = suggestion
-dotnet_diagnostic.CA1825.severity = suggestion
+dotnet_diagnostic.CA1848.severity = suggestion
-dotnet_diagnostic.CA1826.severity = suggestion
-dotnet_diagnostic.CA1827.severity = suggestion
-dotnet_diagnostic.CA1828.severity = suggestion
-dotnet_diagnostic.CA1829.severity = suggestion
-dotnet_diagnostic.CA1834.severity = suggestion
 dotnet_diagnostic.CA2000.severity = suggestion
 dotnet_diagnostic.CA2002.severity = suggestion
 dotnet_diagnostic.CA2007.severity = suggestion
 dotnet_diagnostic.CA2008.severity = suggestion
-dotnet_diagnostic.CA2009.severity = suggestion
-dotnet_diagnostic.CA2010.severity = suggestion
-dotnet_diagnostic.CA2011.severity = suggestion
 dotnet_diagnostic.CA2012.severity = suggestion
 dotnet_diagnostic.CA2013.severity = suggestion
 dotnet_diagnostic.CA2100.severity = suggestion
@@ -236,6 +229,9 @@ dotnet_diagnostic.CA2243.severity = suggestion
 dotnet_diagnostic.CA2244.severity = suggestion
 dotnet_diagnostic.CA2245.severity = suggestion
 dotnet_diagnostic.CA2246.severity = suggestion
+dotnet_diagnostic.CA2249.severity = suggestion
+dotnet_diagnostic.CA2251.severity = suggestion
+dotnet_diagnostic.CA2254.severity = suggestion
 dotnet_diagnostic.CA3061.severity = suggestion
 dotnet_diagnostic.CA3075.severity = suggestion
 dotnet_diagnostic.CA3076.severity = suggestion

src/.globalconfig

@@ -0,0 +1,3 @@
+is_global = true
+
+dotnet_diagnostic.CA1014.severity = none

src/Directory.Build.props

@@ -1,8 +1,10 @@
 <Project>
   <!-- Common to all Lidarr Projects -->
   <PropertyGroup>
+    <AnalysisLevel>6.0-all</AnalysisLevel>
     <TreatWarningsAsErrors>true</TreatWarningsAsErrors>
-	<ErrorOnDuplicatePublishOutputFiles>false</ErrorOnDuplicatePublishOutputFiles>
+    <EnforceCodeStyleInBuild>true</EnforceCodeStyleInBuild>
+    <ErrorOnDuplicatePublishOutputFiles>false</ErrorOnDuplicatePublishOutputFiles>
 
     <PlatformTarget>AnyCPU</PlatformTarget>
     <TargetLatestRuntimePatch>true</TargetLatestRuntimePatch>

src/Lidarr.Api.V1/FileSystem/FileSystemController.cs

@@ -45,7 +45,7 @@ namespace Lidarr.Api.V1.FileSystem
         {
             if (!_diskProvider.FolderExists(path))
             {
-                return new string[0];
+                return global::System.Array.Empty<string>();
             }
 
             return _diskScanService.GetAudioFiles(path).Select(f => new

src/Lidarr.Api.V1/System/Backup/BackupController.cs

@@ -93,7 +93,7 @@ namespace Lidarr.Api.V1.System.Backup
                 throw new BadRequestException("file must be provided");
             }
 
-            var file = files.First();
+            var file = files[0];
             var extension = Path.GetExtension(file.FileName);
 
             if (!ValidExtensions.Contains(extension))

src/Lidarr.Http/Frontend/Mappers/IndexHtmlMapper.cs

@@ -35,7 +35,7 @@ namespace Lidarr.Http.Frontend.Mappers
 
             return !resourceUrl.StartsWith("/content") &&
                    !resourceUrl.StartsWith("/mediacover") &&
-                   !resourceUrl.Contains(".") &&
+                   !resourceUrl.Contains('.') &&
                    !resourceUrl.StartsWith("/login");
         }
     }

src/Lidarr.Http/Middleware/StartingUpMiddleware.cs

@@ -9,9 +9,9 @@ namespace Lidarr.Http.Middleware
 {
     public class StartingUpMiddleware
     {
+        private const string MESSAGE = "Lidarr is starting up, please try again later";
         private readonly RequestDelegate _next;
         private readonly IRuntimeInfo _runtimeInfo;
-        private static readonly string MESSAGE = "Lidarr is starting up, please try again later";
 
         public StartingUpMiddleware(RequestDelegate next, IRuntimeInfo runtimeInfo)
         {
@@ -29,7 +29,7 @@ namespace Lidarr.Http.Middleware
 
                 context.Response.StatusCode = 503;
                 context.Response.ContentType = isJson ? "application/json" : "text/plain";
-                await context.Response.Body.WriteAsync(bytes, 0, bytes.Length);
+                await context.Response.Body.WriteAsync(bytes);
 
                 return;
             }

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

@@ -11,7 +11,7 @@ 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(System.Array.Empty<string>());
             args.Flags.Should().BeEmpty();
         }
 

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

@@ -460,7 +460,7 @@ 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.Resolve<Logger>());
+            var oldClient = new HttpClient(Array.Empty<IHttpRequestInterceptor>(), Mocker.Resolve<ICacheManager>(), Mocker.Resolve<IRateLimitService>(), Mocker.Resolve<IHttpDispatcher>(), Mocker.Resolve<Logger>());
 
             oldClient.Should().NotBeSameAs(Subject);
 

src/NzbDrone.Common/Extensions/FuzzyContains.cs

@@ -91,7 +91,7 @@ namespace NzbDrone.Common.Extensions
             int best_loc = -1;
 
             // Empty initialization added to appease C# compiler.
-            var last_rd = new BigInteger[0];
+            var last_rd = Array.Empty<BigInteger>();
             for (int d = 0; d < pattern.Length; d++)
             {
                 // Scan for the best match; each iteration allows for one more error.

src/NzbDrone.Common/Extensions/StringExtensions.cs

@@ -126,7 +126,7 @@ namespace NzbDrone.Common.Extensions
 
         public static string WrapInQuotes(this string text)
         {
-            if (!text.Contains(" "))
+            if (!text.Contains(' '))
             {
                 return text;
             }
@@ -170,7 +170,7 @@ namespace NzbDrone.Common.Extensions
             {
                 return 0;
             }
-            else if (a.Contains(" ") && b.Contains(" "))
+            else if (a.Contains(' ') && b.Contains(' '))
             {
                 var partsA = a.Split(' ');
                 var partsB = b.Split(' ');
@@ -256,7 +256,7 @@ namespace NzbDrone.Common.Extensions
 
         public static string ToUrlHost(this string input)
         {
-            return input.Contains(":") ? $"[{input}]" : input;
+            return input.Contains(':') ? $"[{input}]" : input;
         }
     }
 }

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.Common/Http/HttpUri.cs

@@ -27,7 +27,7 @@ namespace NzbDrone.Common.Http
             if (scheme.IsNotNullOrWhiteSpace())
             {
                 builder.Append(scheme);
-                builder.Append(":");
+                builder.Append(':');
             }
 
             if (host.IsNotNullOrWhiteSpace())
@@ -36,7 +36,7 @@ namespace NzbDrone.Common.Http
                 builder.Append(host);
                 if (port.HasValue)
                 {
-                    builder.Append(":");
+                    builder.Append(':');
                     builder.Append(port);
                 }
             }
@@ -170,7 +170,7 @@ namespace NzbDrone.Common.Http
 
             if (baseSlashIndex >= 0)
             {
-                return basePath.Substring(0, baseSlashIndex) + "/" + relativePath;
+                return $"{basePath.AsSpan(0, baseSlashIndex)}/{relativePath}";
             }
 
             return relativePath;
@@ -202,11 +202,11 @@ namespace NzbDrone.Common.Http
             {
                 if (builder.Length != 0)
                 {
-                    builder.Append("&");
+                    builder.Append('&');
                 }
 
                 builder.Append(Uri.EscapeDataString(pair.Key));
-                builder.Append("=");
+                builder.Append('=');
                 builder.Append(Uri.EscapeDataString(pair.Value));
             }
 

src/NzbDrone.Common/Http/Proxy/HttpProxySettings.cs

@@ -41,7 +41,7 @@ namespace NzbDrone.Common.Http.Proxy
                     return hostlist;
                 }
 
-                return new string[] { };
+                return System.Array.Empty<string>();
             }
         }
 

src/NzbDrone.Common/OAuth/OAuthRequest.cs

@@ -488,7 +488,7 @@ namespace NzbDrone.Common.OAuth
 
         private static bool IsNullOrBlank(string value)
         {
-            return string.IsNullOrEmpty(value) || (!string.IsNullOrEmpty(value) && value.Trim() == string.Empty);
+            return string.IsNullOrEmpty(value) || (!string.IsNullOrEmpty(value) && string.IsNullOrEmpty(value.Trim()));
         }
     }
 }

src/NzbDrone.Common/OAuth/OAuthTools.cs

@@ -405,7 +405,7 @@ namespace NzbDrone.Common.OAuth
 
         private static bool IsNullOrBlank(string value)
         {
-            return string.IsNullOrEmpty(value) || (!string.IsNullOrEmpty(value) && value.Trim() == string.Empty);
+            return string.IsNullOrEmpty(value) || (!string.IsNullOrEmpty(value) && string.IsNullOrEmpty(value.Trim()));
         }
     }
 }

src/NzbDrone.Common/OAuth/WebParameterCollection.cs

@@ -16,7 +16,7 @@ namespace NzbDrone.Common.OAuth
             {
                 var parameters = this.Where(p => p.Name.Equals(name));
 
-                if (parameters.Count() == 0)
+                if (!parameters.Any())
                 {
                     return null;
                 }

src/NzbDrone.Common/ServiceProvider.cs

@@ -65,7 +65,7 @@ namespace NzbDrone.Common
 
             var args = $"create {serviceName} " +
                 $"DisplayName= \"{serviceName}\" " +
-                $"binpath= \"{Process.GetCurrentProcess().MainModule.FileName}\" " +
+                $"binpath= \"{Environment.ProcessPath}\" " +
                 "start= auto " +
                 "depend= EventLog/Tcpip/http " +
                 "obj= \"NT AUTHORITY\\LocalService\"";

src/NzbDrone.Common/TPL/LimitedConcurrencyLevelTaskScheduler.cs

@@ -1,4 +1,4 @@
-using System;
+using System;
 using System.Collections.Generic;
 using System.Linq;
 using System.Threading;
@@ -19,7 +19,7 @@ namespace NzbDrone.Common.TPL
         private readonly int _maxDegreeOfParallelism;
 
         /// <summary>Whether the scheduler is currently processing work items.</summary>
-        private int _delegatesQueuedOrRunning = 0; // protected by lock(_tasks)
+        private int _delegatesQueuedOrRunning; // protected by lock(_tasks)
 
         /// <summary>
         /// Initializes an instance of the LimitedConcurrencyLevelTaskScheduler class with the

src/NzbDrone.Core.Test/Datastore/Migration/023_add_release_groups_etcFixture.cs

@@ -78,7 +78,7 @@ namespace NzbDrone.Core.Test.Datastore.Migration
             var albums = db.Query<Album>("SELECT * FROM \"Albums\"");
 
             // we only put in one release per album
-            releases.Count().Should().Be(albums.Count());
+            releases.Count.Should().Be(albums.Count);
 
             // each album should be linked to exactly one release
             releases.Select(x => x.AlbumId).SequenceEqual(albums.Select(x => x.Id)).Should().Be(true);

src/NzbDrone.Core.Test/Datastore/Migration/030_add_mediafilerepository_mtimeFixture.cs

@@ -15,7 +15,7 @@ namespace NzbDrone.Core.Test.Datastore.Migration
     [TestFixture]
     public class add_mediafilerepository_mtimeFixture : MigrationTest<add_mediafilerepository_mtime>
     {
-        private string _artistPath = null;
+        private string _artistPath;
 
         private void GivenArtist(add_mediafilerepository_mtime c, int id, string name)
         {

src/NzbDrone.Core.Test/Datastore/Migration/031_add_artistmetadataid_constraintFixture.cs

@@ -11,7 +11,7 @@ namespace NzbDrone.Core.Test.Datastore.Migration
     [TestFixture]
     public class add_artistmetadataid_constraintFixture : MigrationTest<add_artistmetadataid_constraint>
     {
-        private string _artistPath = null;
+        private string _artistPath;
 
         private void GivenArtistMetadata(add_artistmetadataid_constraint c, int id, string name)
         {

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

@@ -34,7 +34,7 @@ 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

@@ -278,7 +278,7 @@ 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/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()
@@ -522,7 +522,7 @@ 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 remoteAlbum = CreateRemoteAlbum();
 

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

@@ -544,7 +544,7 @@ 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

@@ -130,7 +130,7 @@ 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();
@@ -150,7 +150,7 @@ 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

@@ -27,7 +27,7 @@ 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>(), TestLogger));
+            Mocker.SetConstant<IHttpClient>(new HttpClient(Array.Empty<IHttpRequestInterceptor>(), Mocker.Resolve<CacheManager>(), Mocker.Resolve<RateLimitService>(), Mocker.Resolve<IHttpDispatcher>(), TestLogger));
             Mocker.SetConstant<ILidarrCloudRequestBuilder>(new LidarrCloudRequestBuilder());
             Mocker.SetConstant<IMetadataRequestBuilder>(Mocker.Resolve<MetadataRequestBuilder>());
         }

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(It.IsAny<bool>()))
-                  .Returns(new IDownloadClient[0]);
+                  .Returns(Array.Empty<IDownloadClient>());
 
             Subject.Check().ShouldBeWarning();
         }

src/NzbDrone.Core.Test/ImportListTests/Spotify/SpotifyFollowedArtistsFixture.cs

@@ -12,9 +12,6 @@ namespace NzbDrone.Core.Test.ImportListTests
     [TestFixture]
     public class SpotifyFollowedArtistsFixture : CoreTest<SpotifyFollowedArtists>
     {
-        // placeholder, we don't use real API
-        private readonly SpotifyWebAPI _api = null;
-
         [Test]
         public void should_not_throw_if_followed_is_null()
         {
@@ -23,7 +20,7 @@ namespace NzbDrone.Core.Test.ImportListTests
                                                 It.IsAny<SpotifyWebAPI>()))
                 .Returns(default(FollowedArtists));
 
-            var result = Subject.Fetch(_api);
+            var result = Subject.Fetch(null);
 
             result.Should().BeEmpty();
         }
@@ -41,7 +38,7 @@ namespace NzbDrone.Core.Test.ImportListTests
                                                 It.IsAny<SpotifyWebAPI>()))
                 .Returns(followed);
 
-            var result = Subject.Fetch(_api);
+            var result = Subject.Fetch(null);
 
             result.Should().BeEmpty();
         }
@@ -62,10 +59,10 @@ namespace NzbDrone.Core.Test.ImportListTests
                                                 It.IsAny<SpotifyWebAPI>()))
                 .Returns(followed);
 
-            var result = Subject.Fetch(_api);
+            var result = Subject.Fetch(null);
 
             result.Should().BeEmpty();
-            Subject.Fetch(_api);
+            Subject.Fetch(null);
         }
 
         [Test]
@@ -87,10 +84,10 @@ namespace NzbDrone.Core.Test.ImportListTests
                                                 It.IsAny<SpotifyWebAPI>()))
                 .Returns(followed);
 
-            var result = Subject.Fetch(_api);
+            var result = Subject.Fetch(null);
 
             result.Should().BeEmpty();
-            Subject.Fetch(_api);
+            Subject.Fetch(null);
         }
 
         [Test]
@@ -115,7 +112,7 @@ namespace NzbDrone.Core.Test.ImportListTests
                                                 It.IsAny<SpotifyWebAPI>()))
                 .Returns(followed);
 
-            var result = Subject.Fetch(_api);
+            var result = Subject.Fetch(null);
 
             result.Should().HaveCount(1);
         }
@@ -149,7 +146,7 @@ namespace NzbDrone.Core.Test.ImportListTests
                                           It.IsAny<FollowedArtists>()))
                 .Returns(default(FollowedArtists));
 
-            var result = Subject.Fetch(_api);
+            var result = Subject.Fetch(null);
 
             result.Should().HaveCount(1);
 
@@ -183,7 +180,7 @@ namespace NzbDrone.Core.Test.ImportListTests
                                                 It.IsAny<SpotifyWebAPI>()))
                 .Returns(followed);
 
-            var result = Subject.Fetch(_api);
+            var result = Subject.Fetch(null);
 
             result.Should().BeEmpty();
         }

src/NzbDrone.Core.Test/ImportListTests/Spotify/SpotifyMappingFixture.cs

@@ -48,7 +48,7 @@ namespace NzbDrone.Core.Test.ImportListTests
         {
             Mocker.GetMock<IHttpClient>()
                 .Setup(x => x.Get<ArtistResource>(It.IsAny<HttpRequest>()))
-                .Returns<HttpRequest>((x) => new HttpResponse<ArtistResource>(new HttpResponse(x, new HttpHeader(), new byte[0], HttpStatusCode.NotFound)));
+                .Returns<HttpRequest>((x) => new HttpResponse<ArtistResource>(new HttpResponse(x, new HttpHeader(), Array.Empty<byte>(), HttpStatusCode.NotFound)));
 
             var data = new SpotifyImportListItemInfo
             {
@@ -120,7 +120,7 @@ namespace NzbDrone.Core.Test.ImportListTests
         {
             Mocker.GetMock<IHttpClient>()
                 .Setup(x => x.Get<AlbumResource>(It.IsAny<HttpRequest>()))
-                .Returns<HttpRequest>((x) => new HttpResponse<AlbumResource>(new HttpResponse(x, new HttpHeader(), new byte[0], HttpStatusCode.NotFound)));
+                .Returns<HttpRequest>((x) => new HttpResponse<AlbumResource>(new HttpResponse(x, new HttpHeader(), Array.Empty<byte>(), HttpStatusCode.NotFound)));
 
             var data = new SpotifyImportListItemInfo
             {

src/NzbDrone.Core.Test/ImportListTests/Spotify/SpotifyPlaylistFixture.cs

@@ -12,9 +12,6 @@ namespace NzbDrone.Core.Test.ImportListTests
     [TestFixture]
     public class SpotifyPlaylistFixture : CoreTest<SpotifyPlaylist>
     {
-        // placeholder, we don't use real API
-        private readonly SpotifyWebAPI _api = null;
-
         [Test]
         public void should_not_throw_if_playlist_tracks_is_null()
         {
@@ -25,7 +22,7 @@ namespace NzbDrone.Core.Test.ImportListTests
                                                It.IsAny<string>()))
                 .Returns(default(Paging<PlaylistTrack>));
 
-            var result = Subject.Fetch(_api, "playlistid");
+            var result = Subject.Fetch(null, "playlistid");
 
             result.Should().BeEmpty();
         }
@@ -45,7 +42,7 @@ namespace NzbDrone.Core.Test.ImportListTests
                                                It.IsAny<string>()))
                 .Returns(playlistTracks);
 
-            var result = Subject.Fetch(_api, "playlistid");
+            var result = Subject.Fetch(null, "playlistid");
 
             result.Should().BeEmpty();
         }
@@ -68,7 +65,7 @@ namespace NzbDrone.Core.Test.ImportListTests
                                                It.IsAny<string>()))
                 .Returns(playlistTracks);
 
-            var result = Subject.Fetch(_api, "playlistid");
+            var result = Subject.Fetch(null, "playlistid");
 
             result.Should().BeEmpty();
         }
@@ -114,7 +111,7 @@ namespace NzbDrone.Core.Test.ImportListTests
                                                It.IsAny<string>()))
                 .Returns(playlistTracks);
 
-            var result = Subject.Fetch(_api, "playlistid");
+            var result = Subject.Fetch(null, "playlistid");
 
             result.Should().HaveCount(1);
             result[0].Artist.Should().Be("AlbumArtist");
@@ -161,7 +158,7 @@ namespace NzbDrone.Core.Test.ImportListTests
                                                It.IsAny<string>()))
                 .Returns(playlistTracks);
 
-            var result = Subject.Fetch(_api, "playlistid");
+            var result = Subject.Fetch(null, "playlistid");
 
             result.Should().HaveCount(1);
             result[0].Artist.Should().Be("TrackArtist");
@@ -210,7 +207,7 @@ namespace NzbDrone.Core.Test.ImportListTests
                                                It.IsAny<string>()))
                 .Returns(playlistTracks);
 
-            var result = Subject.Fetch(_api, "playlistid");
+            var result = Subject.Fetch(null, "playlistid");
 
             result.Should().BeEmpty();
         }
@@ -263,7 +260,7 @@ namespace NzbDrone.Core.Test.ImportListTests
                                           It.IsAny<Paging<PlaylistTrack>>()))
                 .Returns(default(Paging<PlaylistTrack>));
 
-            var result = Subject.Fetch(_api, "playlistid");
+            var result = Subject.Fetch(null, "playlistid");
 
             result.Should().HaveCount(1);
 

src/NzbDrone.Core.Test/ImportListTests/Spotify/SpotifySavedAlbumsFixture.cs

@@ -12,9 +12,6 @@ namespace NzbDrone.Core.Test.ImportListTests
     [TestFixture]
     public class SpotifySavedAlbumsFixture : CoreTest<SpotifySavedAlbums>
     {
-        // placeholder, we don't use real API
-        private readonly SpotifyWebAPI _api = null;
-
         [Test]
         public void should_not_throw_if_saved_albums_is_null()
         {
@@ -23,7 +20,7 @@ namespace NzbDrone.Core.Test.ImportListTests
                                                 It.IsAny<SpotifyWebAPI>()))
                 .Returns(default(Paging<SavedAlbum>));
 
-            var result = Subject.Fetch(_api);
+            var result = Subject.Fetch(null);
 
             result.Should().BeEmpty();
         }
@@ -41,7 +38,7 @@ namespace NzbDrone.Core.Test.ImportListTests
                                                 It.IsAny<SpotifyWebAPI>()))
                 .Returns(savedAlbums);
 
-            var result = Subject.Fetch(_api);
+            var result = Subject.Fetch(null);
 
             result.Should().BeEmpty();
         }
@@ -62,7 +59,7 @@ namespace NzbDrone.Core.Test.ImportListTests
                                                 It.IsAny<SpotifyWebAPI>()))
                 .Returns(savedAlbums);
 
-            var result = Subject.Fetch(_api);
+            var result = Subject.Fetch(null);
 
             result.Should().BeEmpty();
         }
@@ -96,7 +93,7 @@ namespace NzbDrone.Core.Test.ImportListTests
                                                 It.IsAny<SpotifyWebAPI>()))
                 .Returns(savedAlbums);
 
-            var result = Subject.Fetch(_api);
+            var result = Subject.Fetch(null);
 
             result.Should().HaveCount(1);
         }
@@ -137,7 +134,7 @@ namespace NzbDrone.Core.Test.ImportListTests
                                           It.IsAny<Paging<SavedAlbum>>()))
                 .Returns(default(Paging<SavedAlbum>));
 
-            var result = Subject.Fetch(_api);
+            var result = Subject.Fetch(null);
 
             result.Should().HaveCount(1);
 
@@ -179,7 +176,7 @@ namespace NzbDrone.Core.Test.ImportListTests
                                                 It.IsAny<SpotifyWebAPI>()))
                 .Returns(savedAlbums);
 
-            var result = Subject.Fetch(_api);
+            var result = Subject.Fetch(null);
 
             result.Should().BeEmpty();
         }

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

@@ -86,7 +86,7 @@ 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/AudioTagServiceFixture.cs

@@ -240,9 +240,9 @@ namespace NzbDrone.Core.Test.MediaFiles.AudioTagServiceFixture
             var tag = Subject.ReadAudioTag(path);
             var expected = new AudioTag()
             {
-                Performers = new string[0],
+                Performers = Array.Empty<string>(),
-                AlbumArtists = new string[0],
+                AlbumArtists = Array.Empty<string>(),
-                Genres = new string[0]
+                Genres = Array.Empty<string>()
             };
 
             VerifySame(tag, expected, skipProperties);

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

@@ -96,7 +96,7 @@ namespace NzbDrone.Core.Test.MediaFiles
         private void WasImportedResponse()
         {
             Mocker.GetMock<IDiskScanService>().Setup(c => c.GetAudioFiles(It.IsAny<string>(), It.IsAny<bool>()))
-                  .Returns(new IFileInfo[0]);
+                  .Returns(System.Array.Empty<IFileInfo>());
         }
 
         [Test]
@@ -147,7 +147,7 @@ namespace NzbDrone.Core.Test.MediaFiles
 
             Mocker.GetMock<IDiskScanService>()
                   .Setup(c => c.GetAudioFiles(It.IsAny<string>(), It.IsAny<bool>()))
-                  .Returns(new IFileInfo[0]);
+                  .Returns(System.Array.Empty<IFileInfo>());
 
             Subject.ProcessRootFolder(DiskProvider.GetDirectoryInfo(_droneFactory));
 

src/NzbDrone.Core.Test/MediaFiles/MediaFileDeletionService/DeleteTrackFileFixture.cs

@@ -14,7 +14,7 @@ namespace NzbDrone.Core.Test.MediaFiles.MediaFileDeletionService
     [TestFixture]
     public class DeleteTrackFileFixture : CoreTest<Core.MediaFiles.MediaFileDeletionService>
     {
-        private static readonly string RootFolder = @"C:\Test\Music";
+        private const string RootFolder = @"C:\Test\Music";
         private Artist _artist;
         private TrackFile _trackFile;
 

src/NzbDrone.Core/Configuration/ConfigFileProvider.cs

@@ -266,7 +266,7 @@ namespace NzbDrone.Core.Configuration
 
                     var valueHolder = parentContainer.Descendants(key).ToList();
 
-                    if (valueHolder.Count() == 1)
+                    if (valueHolder.Count == 1)
                     {
                         return valueHolder.First().Value.Trim();
                     }

src/NzbDrone.Core/Datastore/Migration/Framework/SqliteSyntaxReader.cs

@@ -250,7 +250,7 @@ namespace NzbDrone.Core.Datastore.Migration.Framework
                 }
 
                 Index = end + 1;
-                identifier.Append(Buffer.Substring(start, end - start));
+                identifier.Append(Buffer.AsSpan(start, end - start));
 
                 if (Buffer[Index] != escape)
                 {

src/NzbDrone.Core/Datastore/WhereBuilderPostgres.cs

@@ -15,9 +15,9 @@ namespace NzbDrone.Core.Datastore
 
         private const DbType EnumerableMultiParameter = (DbType)(-1);
         private readonly string _paramNamePrefix;
-        private readonly bool _requireConcreteValue = false;
+        private readonly bool _requireConcreteValue;
-        private int _paramCount = 0;
+        private int _paramCount;
-        private bool _gotConcreteValue = false;
+        private bool _gotConcreteValue;
 
         public WhereBuilderPostgres(Expression filter, bool requireConcreteValue, int seq)
         {

src/NzbDrone.Core/Datastore/WhereBuilderSqlite.cs

@@ -15,9 +15,9 @@ namespace NzbDrone.Core.Datastore
 
         private const DbType EnumerableMultiParameter = (DbType)(-1);
         private readonly string _paramNamePrefix;
-        private readonly bool _requireConcreteValue = false;
+        private readonly bool _requireConcreteValue;
-        private int _paramCount = 0;
+        private int _paramCount;
-        private bool _gotConcreteValue = false;
+        private bool _gotConcreteValue;
 
         public WhereBuilderSqlite(Expression filter, bool requireConcreteValue, int seq)
         {
@@ -44,7 +44,7 @@ namespace NzbDrone.Core.Datastore
 
         protected override Expression VisitBinary(BinaryExpression expression)
         {
-            _sb.Append("(");
+            _sb.Append('(');
 
             Visit(expression.Left);
 
@@ -52,7 +52,7 @@ namespace NzbDrone.Core.Datastore
 
             Visit(expression.Right);
 
-            _sb.Append(")");
+            _sb.Append(')');
 
             return expression;
         }
@@ -309,7 +309,7 @@ namespace NzbDrone.Core.Datastore
                 item = body.Arguments[1];
             }
 
-            _sb.Append("(");
+            _sb.Append('(');
 
             Visit(item);
 
@@ -319,9 +319,9 @@ namespace NzbDrone.Core.Datastore
             if (item.Type == typeof(int) && TryGetRightValue(list, out var value))
             {
                 var items = (IEnumerable<int>)value;
-                _sb.Append("(");
+                _sb.Append('(');
                 _sb.Append(string.Join(", ", items));
-                _sb.Append(")");
+                _sb.Append(')');
 
                 _gotConcreteValue = true;
             }
@@ -330,12 +330,12 @@ namespace NzbDrone.Core.Datastore
                 Visit(list);
             }
 
-            _sb.Append(")");
+            _sb.Append(')');
         }
 
         private void ParseStringContains(MethodCallExpression body)
         {
-            _sb.Append("(");
+            _sb.Append('(');
 
             Visit(body.Object);
 
@@ -348,7 +348,7 @@ namespace NzbDrone.Core.Datastore
 
         private void ParseStartsWith(MethodCallExpression body)
         {
-            _sb.Append("(");
+            _sb.Append('(');
 
             Visit(body.Object);
 
@@ -361,7 +361,7 @@ namespace NzbDrone.Core.Datastore
 
         private void ParseEndsWith(MethodCallExpression body)
         {
-            _sb.Append("(");
+            _sb.Append('(');
 
             Visit(body.Object);
 
@@ -369,7 +369,7 @@ namespace NzbDrone.Core.Datastore
 
             Visit(body.Arguments[0]);
 
-            _sb.Append(")");
+            _sb.Append(')');
         }
 
         public override string ToString()

src/NzbDrone.Core/DecisionEngine/DownloadDecisionMaker.cs

@@ -185,7 +185,7 @@ namespace NzbDrone.Core.DecisionEngine
 
         private DownloadDecision GetDecisionForReport(RemoteAlbum remoteAlbum, 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/DecisionEngine/Specifications/AlreadyImportedSpecification.cs

@@ -46,7 +46,7 @@ namespace NzbDrone.Core.DecisionEngine.Specifications
             {
                 var trackFiles = _mediaFileService.GetFilesByAlbum(album.Id);
 
-                if (trackFiles.Count() == 0)
+                if (trackFiles.Count == 0)
                 {
                     _logger.Debug("Skipping already imported check for album without files");
                     continue;

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

@@ -361,7 +361,7 @@ 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/Clients/Sabnzbd/JsonConverters/SabnzbdQueueTimeConverter.cs

@@ -16,7 +16,7 @@ namespace NzbDrone.Core.Download.Clients.Sabnzbd.JsonConverters
         {
             var split = reader.Value.ToString().Split(':').Select(int.Parse).ToArray();
 
-            switch (split.Count())
+            switch (split.Length)
             {
                 case 4:
                     return new TimeSpan((split[0] * 24) + split[1], split[2], split[3]);

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

@@ -116,9 +116,9 @@ namespace NzbDrone.Core.Download.Pending
                             _logger.Debug("The release {0} is already pending with reason {1}, not adding again", decision.RemoteAlbum, reason);
                         }
 
-                        if (matchingReports.Count() > 1)
+                        if (matchingReports.Count > 1)
                         {
-                            _logger.Debug("The release {0} had {1} duplicate pending, removing duplicates.", decision.RemoteAlbum, matchingReports.Count() - 1);
+                            _logger.Debug("The release {0} had {1} duplicate pending, removing duplicates.", decision.RemoteAlbum, matchingReports.Count - 1);
 
                             foreach (var duplicate in matchingReports.Skip(1))
                             {

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

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

src/NzbDrone.Core/Extras/Lyrics/LyricService.cs

@@ -111,7 +111,7 @@ namespace NzbDrone.Core.Extras.Lyrics
 
             if (multipleCopies)
             {
-                suffixBuilder.Append(".");
+                suffixBuilder.Append('.');
                 suffixBuilder.Append(copy);
             }
 

src/NzbDrone.Core/HealthCheck/HealthCheckService.cs

@@ -34,8 +34,8 @@ namespace NzbDrone.Core.HealthCheck
 
         private readonly ICached<HealthCheck> _healthCheckResults;
 
-        private bool _hasRunHealthChecksAfterGracePeriod = false;
+        private bool _hasRunHealthChecksAfterGracePeriod;
-        private bool _isRunningHealthChecksAfterGracePeriod = false;
+        private bool _isRunningHealthChecksAfterGracePeriod;
 
         public HealthCheckService(IEnumerable<IProvideHealthCheck> healthChecks,
                                   IServerSideNotificationService serverSideNotificationService,

src/NzbDrone.Core/ImportLists/Spotify/SpotifyPlaylistSettings.cs

@@ -19,7 +19,7 @@ namespace NzbDrone.Core.ImportLists.Spotify
 
         public SpotifyPlaylistSettings()
         {
-            PlaylistIds = new string[] { };
+            PlaylistIds = System.Array.Empty<string>();
         }
 
         public override string Scope => "playlist-read-private";

src/NzbDrone.Core/Indexers/TorrentRss/TorrentRssSettingsDetector.cs

@@ -176,7 +176,7 @@ namespace NzbDrone.Core.Indexers.TorrentRss
             releases = ParseResponse(parser, response);
             ValidateReleases(releases, indexerSettings);
 
-            if (releases.Count(r => r.Size >= ValidSizeThreshold) > releases.Count() / 2)
+            if (releases.Count(r => r.Size >= ValidSizeThreshold) > releases.Length / 2)
             {
                 if (releases.Any(r => r.Size < ValidSizeThreshold))
                 {

src/NzbDrone.Core/Localization/LocalizationService.cs

@@ -127,7 +127,7 @@ namespace NzbDrone.Core.Localization
 
             await CopyInto(dictionary, baseFilenamePath).ConfigureAwait(false);
 
-            if (culture.Contains("_"))
+            if (culture.Contains('_'))
             {
                 var languageBaseFilenamePath = Path.Combine(prefix, GetResourceFilename(culture.Split('_')[0]));
                 await CopyInto(dictionary, languageBaseFilenamePath).ConfigureAwait(false);

src/NzbDrone.Core/MediaCover/MediaCoverService.cs

@@ -283,7 +283,7 @@ namespace NzbDrone.Core.MediaCover
             switch (coverType)
             {
                 default:
-                    return new int[] { };
+                    return Array.Empty<int>();
 
                 case MediaCoverTypes.Poster:
                 case MediaCoverTypes.Disc:

src/NzbDrone.Core/MediaFiles/AudioTag.cs

@@ -324,9 +324,9 @@ namespace NzbDrone.Core.MediaFiles
 
             // patch up any null fields to work around TagLib exception for
             // WMA with null performers/albumartists
-            Performers = Performers ?? new string[0];
+            Performers = Performers ?? Array.Empty<string>();
-            AlbumArtists = AlbumArtists ?? new string[0];
+            AlbumArtists = AlbumArtists ?? Array.Empty<string>();
-            Genres = Genres ?? new string[0];
+            Genres = Genres ?? Array.Empty<string>();
 
             TagLib.File file = null;
             try

src/NzbDrone.Core/MediaFiles/MediaFileService.cs

@@ -209,7 +209,7 @@ namespace NzbDrone.Core.MediaFiles
 
             foreach (var file in files)
             {
-                var newPath = message.DestinationPath + file.Path.Substring(message.SourcePath.Length);
+                var newPath = $"{message.DestinationPath}{file.Path.AsSpan(message.SourcePath.Length)}";
                 file.Path = newPath;
             }
 

src/NzbDrone.Core/MediaFiles/TrackImport/Aggregation/Aggregators/AggregateFilenameInfo.cs

@@ -58,9 +58,9 @@ namespace NzbDrone.Core.MediaFiles.TrackImport.Aggregation.Aggregators
         public LocalAlbumRelease Aggregate(LocalAlbumRelease release, bool others)
         {
             var tracks = release.LocalTracks;
-            if (tracks.Count(x => x.FileTrackInfo.Title.IsNullOrWhiteSpace()) > 0
+            if (tracks.Any(x => x.FileTrackInfo.Title.IsNullOrWhiteSpace())
-                || tracks.Count(x => x.FileTrackInfo.TrackNumbers.First() == 0) > 0
+                || tracks.Any(x => x.FileTrackInfo.TrackNumbers.First() == 0)
-                || tracks.Count(x => x.FileTrackInfo.DiscNumber == 0) > 0)
+                || tracks.Any(x => x.FileTrackInfo.DiscNumber == 0))
             {
                 _logger.Debug("Missing data in tags, trying filename augmentation");
                 foreach (var charSep in CharsAndSeps)
@@ -171,7 +171,7 @@ namespace NzbDrone.Core.MediaFiles.TrackImport.Aggregation.Aggregators
                 }
 
                 var trackNums = track.FileTrackInfo.TrackNumbers;
-                if (keys.Contains("track") && (trackNums.Count() == 0 || trackNums.First() == 0))
+                if (keys.Contains("track") && (trackNums.Length == 0 || trackNums.First() == 0))
                 {
                     var tracknum = Convert.ToInt32(matches[track].Groups["track"].Value);
                     if (tracknum > 100)

src/NzbDrone.Core/MediaFiles/TrackImport/Identification/Distance.cs

@@ -39,7 +39,7 @@ namespace NzbDrone.Core.MediaFiles.TrackImport.Identification
         }
 
         public Dictionary<string, List<double>> Penalties => _penalties;
-        public string Reasons => _penalties.Count(x => x.Value.Max() > 0.0) > 0 ? "[" + string.Join(", ", Penalties.Where(x => x.Value.Max() > 0.0).Select(x => x.Key.Replace('_', ' '))) + "]" : string.Empty;
+        public string Reasons => _penalties.Any(x => x.Value.Max() > 0.0) ? "[" + string.Join(", ", Penalties.Where(x => x.Value.Max() > 0.0).Select(x => x.Key.Replace('_', ' '))) + "]" : string.Empty;
 
         private double MaxDistance(Dictionary<string, List<double>> penalties)
         {

src/NzbDrone.Core/MediaFiles/TrackImport/Identification/TrackGroupingService.cs

@@ -19,10 +19,10 @@ namespace NzbDrone.Core.MediaFiles.TrackImport.Identification
 
     public class TrackGroupingService : ITrackGroupingService
     {
+        private const string MultiDiscPatternFormat = @"^(?<root>.*%s[\W_]*)\d";
         private static readonly Logger _logger = NzbDroneLogger.GetLogger(typeof(TrackGroupingService));
 
         private static readonly List<string> MultiDiscMarkers = new List<string> { @"dis[ck]", @"cd" };
-        private static readonly string MultiDiscPatternFormat = @"^(?<root>.*%s[\W_]*)\d";
         private static readonly List<string> VariousArtistTitles = new List<string> { "", "various artists", "various", "va", "unknown" };
 
         public List<LocalAlbumRelease> GroupTracks(List<LocalTrack> localTracks)

src/NzbDrone.Core/Notifications/Discord/Discord.cs

@@ -69,7 +69,7 @@ namespace NzbDrone.Core.Notifications.Discord
                     case DiscordGrabFieldType.Overview:
                         var overview = albums.First().Overview ?? "";
                         discordField.Name = "Overview";
-                        discordField.Value = overview.Length <= 300 ? overview : overview.Substring(0, 300) + "...";
+                        discordField.Value = overview.Length <= 300 ? overview : $"{overview.AsSpan(0, 300)}...";
                         break;
                     case DiscordGrabFieldType.Rating:
                         discordField.Name = "Rating";
@@ -162,7 +162,7 @@ namespace NzbDrone.Core.Notifications.Discord
                     case DiscordImportFieldType.Overview:
                         var overview = album.Overview ?? "";
                         discordField.Name = "Overview";
-                        discordField.Value = overview.Length <= 300 ? overview : overview.Substring(0, 300) + "...";
+                        discordField.Value = overview.Length <= 300 ? overview : $"{overview.AsSpan(0, 300)}...";
                         break;
                     case DiscordImportFieldType.Rating:
                         discordField.Name = "Rating";

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

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

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

@@ -20,8 +20,8 @@ namespace NzbDrone.Core.Notifications.PushBullet
 
         public PushBulletSettings()
         {
-            DeviceIds = new string[] { };
+            DeviceIds = System.Array.Empty<string>();
-            ChannelTags = new string[] { };
+            ChannelTags = System.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

@@ -23,7 +23,7 @@ namespace NzbDrone.Core.Notifications.Pushover
         public PushoverSettings()
         {
             Priority = 0;
-            Devices = new string[] { };
+            Devices = System.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

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

src/NzbDrone.Core/Organizer/FileNameBuilder.cs

@@ -102,7 +102,7 @@ namespace NzbDrone.Core.Organizer
 
             var pattern = namingConfig.StandardTrackFormat;
 
-            if (tracks.First().AlbumRelease.Value.Media.Count() > 1)
+            if (tracks.First().AlbumRelease.Value.Media.Count > 1)
             {
                 pattern = namingConfig.MultiDiscTrackFormat;
             }

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

@@ -33,7 +33,7 @@ namespace NzbDrone.Core.Parser.Model
 
         public ParsedTrackInfo()
         {
-            TrackNumbers = new int[0];
+            TrackNumbers = Array.Empty<int>();
         }
 
         public override string ToString()

src/NzbDrone.Core/Parser/SceneChecker.cs

@@ -6,12 +6,12 @@ namespace NzbDrone.Core.Parser
         // It's better not to use a title that might be scene than to use one that isn't scene
         public static bool IsSceneTitle(string title)
         {
-            if (!title.Contains("."))
+            if (!title.Contains('.'))
             {
                 return false;
             }
 
-            if (title.Contains(" "))
+            if (title.Contains(' '))
             {
                 return false;
             }

src/NzbDrone.Host/Startup.cs

@@ -127,7 +127,7 @@ namespace NzbDrone.Host
 
                 c.AddSecurityRequirement(new OpenApiSecurityRequirement
                 {
-                    { apiKeyHeader, new string[] { } }
+                    { apiKeyHeader, Array.Empty<string>() }
                 });
 
                 var apikeyQuery = new OpenApiSecurityScheme
@@ -158,7 +158,7 @@ namespace NzbDrone.Host
 
                 c.AddSecurityRequirement(new OpenApiSecurityRequirement
                 {
-                    { apikeyQuery, new string[] { } }
+                    { apikeyQuery, Array.Empty<string>() }
                 });
             });
 

src/NzbDrone.Mono.Test/EnvironmentInfo/VersionAdapters/ReleaseFileVersionAdapterFixture.cs

@@ -48,7 +48,7 @@ namespace NzbDrone.Mono.Test.EnvironmentInfo.VersionAdapters
             Subject.Read().Should().BeNull();
 
             Mocker.GetMock<IDiskProvider>()
-              .Setup(c => c.GetFiles(It.IsAny<string>(), SearchOption.TopDirectoryOnly)).Returns(new string[0]);
+              .Setup(c => c.GetFiles(It.IsAny<string>(), SearchOption.TopDirectoryOnly)).Returns(System.Array.Empty<string>());
 
             Subject.Read().Should().BeNull();
         }

src/NzbDrone.Mono/Disk/ProcMountProvider.cs

@@ -26,7 +26,7 @@ namespace NzbDrone.Mono.Disk
         private static Dictionary<string, bool> _fileSystems;
 
         private readonly Logger _logger;
-        private bool _hasLoggedProcMountFailure = false;
+        private bool _hasLoggedProcMountFailure;
 
         public ProcMountProvider(Logger logger)
         {

src/NzbDrone.Mono/Disk/SymbolicLinkResolver.cs

@@ -2,6 +2,7 @@ using System;
 using Mono.Unix;
 using Mono.Unix.Native;
 using NLog;
+using NzbDrone.Common.Extensions;
 
 namespace NzbDrone.Mono.Disk
 {
@@ -55,7 +56,7 @@ namespace NzbDrone.Mono.Disk
             var target = 0;
             for (var i = 0; i < dirs.Length; ++i)
             {
-                if (dirs[i] == "." || dirs[i] == string.Empty)
+                if (dirs[i] == "." || dirs[i].IsNullOrWhiteSpace())
                 {
                     continue;
                 }

src/NzbDrone.Test.Common/ConcurrencyCounter.cs

@@ -27,7 +27,7 @@ namespace NzbDrone.Test.Common
 
         public int Start()
         {
-            int threadId = Thread.CurrentThread.ManagedThreadId;
+            int threadId = Environment.CurrentManagedThreadId;
             lock (_mutex)
             {
                 _threads[threadId] = 1;

src/NzbDrone.Test.Common/TestBase.cs

@@ -53,7 +53,7 @@ namespace NzbDrone.Test.Common
                 {
                     _mocker = new AutoMoqer();
                     _mocker.SetConstant<ICacheManager>(new CacheManager());
-                    _mocker.SetConstant<IStartupContext>(new StartupContext(new string[0]));
+                    _mocker.SetConstant<IStartupContext>(new StartupContext(Array.Empty<string>()));
                     _mocker.SetConstant(TestLogger);
                 }
 

src/NzbDrone.Update/UpdateApp.cs

@@ -74,7 +74,7 @@ namespace NzbDrone.Update
 
             if (OsInfo.IsNotWindows)
             {
-                switch (args.Count())
+                switch (args.Length)
                 {
                     case 1:
                         return startupContext;