Drop .NET 6

Directory.Build.props

@@ -52,11 +52,6 @@
     <NoWarn>$(NoWarn);CA1062</NoWarn>
   </PropertyGroup>
 
-  <PropertyGroup Condition="'$(TargetFramework)' == 'net6.0'">
-    <!-- Workaround for https://github.com/dotnet/runtime/issues/72263 -->
-    <NoWarn>$(NoWarn);SYSLIB1006</NoWarn>
-  </PropertyGroup>
-
   <ItemGroup>
     <PackageReference Include="JetBrains.Annotations" Version="2024.2.*" PrivateAssets="All" />
     <PackageReference Include="CSharpGuidelinesAnalyzer" Version="3.8.*" PrivateAssets="All" />

JsonApiDotNetCore.sln.DotSettings

@@ -14,6 +14,7 @@ JsonApiDotNetCore.ArgumentGuard.NotNull($EXPR$);</s:String>
 	<s:Int64 x:Key="/Default/CodeEditing/NullCheckPatterns/PatternTypeNamesToPriority/=JetBrains_002EReSharper_002EFeature_002EServices_002ECSharp_002ENullChecking_002EThrowExpressionNullCheckPattern/@EntryIndexedValue">3000</s:Int64>
 	<s:Int64 x:Key="/Default/CodeEditing/NullCheckPatterns/PatternTypeNamesToPriority/=JetBrains_002EReSharper_002EFeature_002EServices_002ECSharp_002ENullChecking_002ETraceAssertPattern/@EntryIndexedValue">50</s:Int64>
 	<s:Boolean x:Key="/Default/CodeInspection/CodeAnnotations/PropagateAnnotations/@EntryValue">False</s:Boolean>
+	<s:String x:Key="/Default/CodeInspection/ExcludedFiles/GeneratedFilesAndFolders/=83FF097C_002DC8C6_002D477B_002D9FAB_002DDF99B84978B5_002Ff_003AReadOnlySet_002Ecs/@EntryIndexedValue">83FF097C-C8C6-477B-9FAB-DF99B84978B5/f:ReadOnlySet.cs</s:String>
 	<s:String x:Key="/Default/CodeInspection/Highlighting/AnalysisEnabled/@EntryValue">SOLUTION</s:String>
 	<s:Boolean x:Key="/Default/CodeInspection/Highlighting/IdentifierHighlightingEnabled/@EntryValue">True</s:Boolean>
 	<s:Boolean x:Key="/Default/CodeInspection/Highlighting/IncludeWarningsInSwea/@EntryValue">True</s:Boolean>

README.md

@@ -87,13 +87,9 @@ See also our [versioning policy](./VERSIONING_POLICY.md).
 |                   |              | 7        | 7                     |
 |                   |              | 8        | 8, 9                  |
 |                   |              | 9        | 9                     |
-| master            | Preview      | 6        | 6, 7                  |
-|                   |              | 7        | 7                     |
-|                   |              | 8        | 8, 9                  |
+| master            | Preview      | 8        | 8, 9                  |
 |                   |              | 9        | 9                     |
-| openapi           | Experimental | 6        | 6, 7                  |
-|                   |              | 7        | 7                     |
-|                   |              | 8        | 8, 9                  |
+| openapi           | Experimental | 8        | 8, 9                  |
 |                   |              | 9        | 9                     |
 
 ## Contributing

package-versions.props

@@ -15,6 +15,7 @@
     <GitHubActionsTestLoggerVersion>2.4.*</GitHubActionsTestLoggerVersion>
     <InheritDocVersion>2.0.*</InheritDocVersion>
     <SourceLinkVersion>8.0.*</SourceLinkVersion>
+    <SystemTextJsonVersion>9.0.*</SystemTextJsonVersion>
     <TestSdkVersion>17.11.*</TestSdkVersion>
     <XunitVersion>2.9.*</XunitVersion>
     <XunitVisualStudioVersion>2.8.*</XunitVisualStudioVersion>
@@ -28,7 +29,6 @@
     <AspNetCoreVersion>9.0.*</AspNetCoreVersion>
     <EntityFrameworkCoreVersion>9.0.*</EntityFrameworkCoreVersion>
     <EntityFrameworkCorePomeloVersion>9.0.0-*</EntityFrameworkCorePomeloVersion>
-    <SystemTextJsonVersion>$(AspNetCoreVersion)</SystemTextJsonVersion>
   </PropertyGroup>
 
   <PropertyGroup Condition="'$(TargetFramework)' == 'net8.0'">
@@ -39,18 +39,5 @@
     <AspNetCoreVersion>8.0.*</AspNetCoreVersion>
     <EntityFrameworkCoreVersion>8.0.*</EntityFrameworkCoreVersion>
     <EntityFrameworkCorePomeloVersion>$(EntityFrameworkCoreVersion)</EntityFrameworkCorePomeloVersion>
-    <SystemTextJsonVersion>$(AspNetCoreVersion)</SystemTextJsonVersion>
-  </PropertyGroup>
-
-  <PropertyGroup Condition="'$(TargetFramework)' == 'net6.0'">
-    <!-- Published dependencies (only update on major version change) -->
-    <EntityFrameworkCoreFrozenVersion>6.0.0</EntityFrameworkCoreFrozenVersion>
-
-    <!-- Non-published dependencies (these are safe to update, won't cause a breaking change) -->
-    <AspNetCoreVersion>6.0.*</AspNetCoreVersion>
-    <DateOnlyTimeOnlyVersion>2.1.*</DateOnlyTimeOnlyVersion>
-    <EntityFrameworkCoreVersion>7.0.*</EntityFrameworkCoreVersion>
-    <EntityFrameworkCorePomeloVersion>$(EntityFrameworkCoreVersion)</EntityFrameworkCorePomeloVersion>
-    <SystemTextJsonVersion>8.0.*</SystemTextJsonVersion>
   </PropertyGroup>
 </Project>

src/Examples/DapperExample/DapperExample.csproj

@@ -1,6 +1,6 @@
 <Project Sdk="Microsoft.NET.Sdk.Web">
   <PropertyGroup>
-    <TargetFrameworks>net9.0;net8.0;net6.0</TargetFrameworks>
+    <TargetFrameworks>net9.0;net8.0</TargetFrameworks>
   </PropertyGroup>
 
   <Import Project="..\..\..\package-versions.props" />

src/Examples/DapperExample/Program.cs

@@ -31,10 +31,10 @@
     }
     case DatabaseProvider.MySql:
     {
-#if NET9_0_OR_GREATER
-        ServerVersion serverVersion = await ServerVersion.AutoDetectAsync(connectionString);
-#else
+#if NET8_0
         ServerVersion serverVersion = ServerVersion.AutoDetect(connectionString);
+#else
+        ServerVersion serverVersion = await ServerVersion.AutoDetectAsync(connectionString);
 #endif
 
         builder.Services.AddMySql<AppDbContext>(connectionString, serverVersion, optionsAction: options => SetDbContextDebugOptions(options));

src/Examples/DapperExample/Repositories/ResultSetMapper.cs

@@ -3,9 +3,6 @@
 using JsonApiDotNetCore.Queries.Expressions;
 using JsonApiDotNetCore.Resources;
 using JsonApiDotNetCore.Resources.Annotations;
-#if NET6_0
-using JsonApiDotNetCore;
-#endif
 
 namespace DapperExample.Repositories;
 

src/Examples/DatabasePerTenantExample/DatabasePerTenantExample.csproj

@@ -1,6 +1,6 @@
 <Project Sdk="Microsoft.NET.Sdk.Web">
   <PropertyGroup>
-    <TargetFrameworks>net9.0;net8.0;net6.0</TargetFrameworks>
+    <TargetFrameworks>net9.0;net8.0</TargetFrameworks>
   </PropertyGroup>
 
   <Import Project="..\..\..\package-versions.props" />

src/Examples/GettingStarted/GettingStarted.csproj

@@ -1,6 +1,6 @@
 <Project Sdk="Microsoft.NET.Sdk.Web">
   <PropertyGroup>
-    <TargetFrameworks>net9.0;net8.0;net6.0</TargetFrameworks>
+    <TargetFrameworks>net9.0;net8.0</TargetFrameworks>
   </PropertyGroup>
 
   <Import Project="..\..\..\package-versions.props" />

src/Examples/JsonApiDotNetCoreExample/Definitions/TodoItemDefinition.cs

@@ -5,28 +5,14 @@
 using JsonApiDotNetCore.Queries.Expressions;
 using JsonApiDotNetCore.Resources;
 using JsonApiDotNetCoreExample.Models;
-#if NET6_0
-using Microsoft.AspNetCore.Authentication;
-#endif
 
 namespace JsonApiDotNetCoreExample.Definitions;
 
 [UsedImplicitly(ImplicitUseKindFlags.InstantiatedNoFixedConstructorSignature)]
-public sealed class TodoItemDefinition(
-    IResourceGraph resourceGraph,
-#if NET6_0
-    ISystemClock systemClock
-#else
-    TimeProvider timeProvider
-#endif
-)
+public sealed class TodoItemDefinition(IResourceGraph resourceGraph, TimeProvider timeProvider)
     : JsonApiResourceDefinition<TodoItem, long>(resourceGraph)
 {
-#if NET6_0
-    private readonly Func<DateTimeOffset> _getUtcNow = () => systemClock.UtcNow;
-#else
     private readonly Func<DateTimeOffset> _getUtcNow = timeProvider.GetUtcNow;
-#endif
 
     public override SortExpression OnApplySort(SortExpression? existingSort)
     {

src/Examples/JsonApiDotNetCoreExample/JsonApiDotNetCoreExample.csproj

@@ -1,6 +1,6 @@
 <Project Sdk="Microsoft.NET.Sdk.Web">
   <PropertyGroup>
-    <TargetFrameworks>net9.0;net8.0;net6.0</TargetFrameworks>
+    <TargetFrameworks>net9.0;net8.0</TargetFrameworks>
   </PropertyGroup>
 
   <Import Project="..\..\..\package-versions.props" />

src/Examples/JsonApiDotNetCoreExample/Program.cs

@@ -8,9 +8,6 @@
 using Microsoft.EntityFrameworkCore;
 using Microsoft.EntityFrameworkCore.Diagnostics;
 using Microsoft.Extensions.DependencyInjection.Extensions;
-#if NET6_0
-using Microsoft.AspNetCore.Authentication;
-#endif
 
 [assembly: ExcludeFromCodeCoverage]
 
@@ -48,11 +45,7 @@ static void ConfigureServices(WebApplicationBuilder builder)
 {
     using IDisposable _ = CodeTimingSessionManager.Current.Measure("Configure services");
 
-#if NET6_0
-    builder.Services.TryAddSingleton<ISystemClock, SystemClock>();
-#else
     builder.Services.TryAddSingleton(TimeProvider.System);
-#endif
 
     builder.Services.AddDbContext<AppDbContext>(options =>
     {

src/Examples/MultiDbContextExample/MultiDbContextExample.csproj

@@ -1,6 +1,6 @@
 <Project Sdk="Microsoft.NET.Sdk.Web">
   <PropertyGroup>
-    <TargetFrameworks>net9.0;net8.0;net6.0</TargetFrameworks>
+    <TargetFrameworks>net9.0;net8.0</TargetFrameworks>
   </PropertyGroup>
 
   <Import Project="..\..\..\package-versions.props" />

src/Examples/NoEntityFrameworkExample/NoEntityFrameworkExample.csproj

@@ -1,6 +1,6 @@
 <Project Sdk="Microsoft.NET.Sdk.Web">
   <PropertyGroup>
-    <TargetFrameworks>net9.0;net8.0;net6.0</TargetFrameworks>
+    <TargetFrameworks>net9.0;net8.0</TargetFrameworks>
   </PropertyGroup>
 
   <Import Project="..\..\..\package-versions.props" />

src/Examples/NoEntityFrameworkExample/Repositories/InMemoryResourceRepository.cs

@@ -32,11 +32,7 @@ public Task<IReadOnlyCollection<TResource>> GetAsync(QueryLayer queryLayer, Canc
         IEnumerable<TResource> dataSource = GetDataSource();
         IEnumerable<TResource> resources = _queryLayerToLinqConverter.ApplyQueryLayer(queryLayer, dataSource);
 
-#if NET6_0
-        return Task.FromResult<IReadOnlyCollection<TResource>>(Array.AsReadOnly(resources.ToArray()));
-#else
         return Task.FromResult<IReadOnlyCollection<TResource>>(resources.ToArray().AsReadOnly());
-#endif
     }
 
     /// <inheritdoc />

src/Examples/NoEntityFrameworkExample/Services/InMemoryResourceService.cs

@@ -65,11 +65,7 @@ public Task<IReadOnlyCollection<TResource>> GetAsync(CancellationToken cancellat
             _paginationContext.IsPageFull = true;
         }
 
-#if NET6_0
-        return Task.FromResult<IReadOnlyCollection<TResource>>(Array.AsReadOnly(resources));
-#else
         return Task.FromResult<IReadOnlyCollection<TResource>>(resources.AsReadOnly());
-#endif
     }
 
     private void LogFiltersInTopScope()

src/Examples/ReportsExample/ReportsExample.csproj

@@ -1,6 +1,6 @@
 <Project Sdk="Microsoft.NET.Sdk.Web">
   <PropertyGroup>
-    <TargetFrameworks>net9.0;net8.0;net6.0</TargetFrameworks>
+    <TargetFrameworks>net9.0;net8.0</TargetFrameworks>
   </PropertyGroup>
 
   <Import Project="..\..\..\package-versions.props" />

src/JsonApiDotNetCore.Annotations/ArgumentGuard.cs

@@ -30,30 +30,12 @@ public static void NotNullNorEmpty<T>([SysNotNull] IEnumerable<T>? value, [Calle
     [AssertionMethod]
     public static void NotNullNorEmpty([SysNotNull] string? value, [CallerArgumentExpression(nameof(value))] string? parameterName = null)
     {
-#if !NET6_0
         ArgumentException.ThrowIfNullOrEmpty(value, parameterName);
-#else
-        ArgumentNullException.ThrowIfNull(value, parameterName);
-
-        if (value.Length == 0)
-        {
-            throw new ArgumentException("String cannot be null or empty.", parameterName);
-        }
-#endif
     }
 
     [AssertionMethod]
     public static void NotNullNorWhitespace([SysNotNull] string? value, [CallerArgumentExpression(nameof(value))] string? parameterName = null)
     {
-#if !NET6_0
         ArgumentException.ThrowIfNullOrWhiteSpace(value, parameterName);
-#else
-        ArgumentNullException.ThrowIfNull(value, parameterName);
-
-        if (string.IsNullOrWhiteSpace(value))
-        {
-            throw new ArgumentException("String cannot be null, empty, or whitespace.", parameterName);
-        }
-#endif
     }
 }

src/JsonApiDotNetCore.Annotations/JsonApiDotNetCore.Annotations.csproj

@@ -1,6 +1,6 @@
 <Project Sdk="Microsoft.NET.Sdk">
   <PropertyGroup>
-    <TargetFrameworks>net8.0;net6.0;netstandard1.0</TargetFrameworks>
+    <TargetFrameworks>net8.0;netstandard1.0</TargetFrameworks>
     <IsPackable>true</IsPackable>
     <GeneratePackageOnBuild>true</GeneratePackageOnBuild>
     <RootNamespace>JsonApiDotNetCore</RootNamespace>

src/JsonApiDotNetCore.Annotations/PolyfillCollectionExtensions.cs

@@ -1,10 +1,4 @@
-#if NET6_0
 using System.Collections.ObjectModel;
-#endif
-
-#if NET6_0
-#pragma warning disable AV1130 // Return type in method signature should be an interface to an unchangeable collection
-#endif
 
 namespace JsonApiDotNetCore;
 
@@ -13,22 +7,6 @@ internal static class PolyfillCollectionExtensions
 {
     public static IReadOnlySet<T> AsReadOnly<T>(this HashSet<T> source)
     {
-        // We can't use ReadOnlySet<T> yet, which is being introduced in .NET 9.
-        return source;
-    }
-
-#if NET6_0
-    public static ReadOnlyDictionary<TKey, TValue> AsReadOnly<TKey, TValue>(this IDictionary<TKey, TValue> source)
-        where TKey : notnull
-    {
-        // The AsReadOnly() extension method is unavailable in .NET 6.
-        return new ReadOnlyDictionary<TKey, TValue>(source);
-    }
-
-    public static ReadOnlyCollection<T> AsReadOnly<T>(this T[] source)
-    {
-        // The AsReadOnly() extension method is unavailable in .NET 6.
-        return Array.AsReadOnly(source);
+        return new ReadOnlySet<T>(source);
     }
-#endif
 }