Update to ReSharper 2026.1 (#1930)

* Update to stable R# 2026.1.x

* R#: Switch to new setting to show SWEA warnings in IDE

* Fixed R# warning: Convert into method group

* Fixed R# warning: the nullable suppression is redundant

* R#: Auto-arrange property accessors on cleanup

* R#: Use string.Empty instead of ""

* Fixed R# warning: use string.Empty

* R#: Disable notification about overload resolution change

* R#: Separate local function with return

* R#: Enforce using extension blocks

* Revert "R#: Enforce using extension blocks"

This reverts commit e4d8ad4.

* R#: Use range indexer

* R#: Update member layout to new XML format

* Fix CA1830: Prefer strongly-typed StringBuilder overload

Author: bkoelman

.config/dotnet-tools.json

@@ -3,7 +3,7 @@
   "isRoot": true,
   "tools": {
     "jetbrains.resharper.globaltools": {
-      "version": "2025.3.4",
+      "version": "2026.1.0.1",
       "commands": [
         "jb"
       ],

JsonApiDotNetCore.slnx.DotSettings

@@ -452,7 +452,7 @@ private void AppendOnNewLine(string? value, StringBuilder builder)
                 builder.AppendLine();
             }
 
-            builder.Append(new string(' ', _indentDepth * 4));
+            builder.Append(' ', _indentDepth * 4);
             builder.Append(value);
         }
     }

src/Examples/DapperExample/TranslationToSql/Builders/SqlQueryBuilder.cs

@@ -26,7 +26,7 @@ public AddToRelationshipProcessor(IAddToRelationshipService<TResource, TId> serv
         var leftId = (TId)operation.Resource.GetTypedId();
         ISet<IIdentifiable> rightResourceIds = operation.GetSecondaryResources();
 
-        await _service.AddToToManyRelationshipAsync(leftId!, operation.Request.Relationship!.PublicName, rightResourceIds, cancellationToken);
+        await _service.AddToToManyRelationshipAsync(leftId, operation.Request.Relationship!.PublicName, rightResourceIds, cancellationToken);
 
         return null;
     }

src/JsonApiDotNetCore/AtomicOperations/Processors/AddToRelationshipProcessor.cs

@@ -24,10 +24,7 @@ public DeleteProcessor(IDeleteService<TResource, TId> service)
         ArgumentNullException.ThrowIfNull(operation);
 
         var id = (TId)operation.Resource.GetTypedId();
-#pragma warning disable CS8607 // A possible null value may not be used for a type marked with [NotNull] or [DisallowNull]
-        // Justification: Temporary workaround for R# bug at https://youtrack.jetbrains.com/issue/RSRP-503026.
         await _service.DeleteAsync(id, cancellationToken);
-#pragma warning restore CS8607 // A possible null value may not be used for a type marked with [NotNull] or [DisallowNull]
 
         return null;
     }

src/JsonApiDotNetCore/AtomicOperations/Processors/DeleteProcessor.cs

@@ -26,7 +26,7 @@ public RemoveFromRelationshipProcessor(IRemoveFromRelationshipService<TResource,
         var leftId = (TId)operation.Resource.GetTypedId();
         ISet<IIdentifiable> rightResourceIds = operation.GetSecondaryResources();
 
-        await _service.RemoveFromToManyRelationshipAsync(leftId!, operation.Request.Relationship!.PublicName, rightResourceIds, cancellationToken);
+        await _service.RemoveFromToManyRelationshipAsync(leftId, operation.Request.Relationship!.PublicName, rightResourceIds, cancellationToken);
 
         return null;
     }

src/JsonApiDotNetCore/AtomicOperations/Processors/RemoveFromRelationshipProcessor.cs

@@ -27,7 +27,7 @@ public SetRelationshipProcessor(ISetRelationshipService<TResource, TId> service)
         var leftId = (TId)operation.Resource.GetTypedId();
         object? rightValue = GetRelationshipRightValue(operation);
 
-        await _service.SetRelationshipAsync(leftId!, operation.Request.Relationship!.PublicName, rightValue, cancellationToken);
+        await _service.SetRelationshipAsync(leftId, operation.Request.Relationship!.PublicName, rightValue, cancellationToken);
 
         return null;
     }

src/JsonApiDotNetCore/AtomicOperations/Processors/SetRelationshipProcessor.cs

@@ -263,7 +263,7 @@ private void WriteResult(StringBuilder builder, int indent, TimeSpan timeElapsed
 
         private static void WriteIndent(StringBuilder builder, int indent)
         {
-            builder.Append(new string(' ', indent * 2));
+            builder.Append(' ', indent * 2);
         }
 
         private void WritePadding(StringBuilder builder, int indent, int paddingLength)

src/JsonApiDotNetCore/Diagnostics/CascadingCodeTimer.cs

@@ -98,7 +98,7 @@ public async Task InvokeAsync(HttpContext httpContext, IJsonApiRequest request)
         if (CodeTimingSessionManager.IsEnabled && _logger.IsEnabled(LogLevel.Information))
         {
             string timingResults = CodeTimingSessionManager.Current.GetResults();
-            string requestMethod = httpContext.Request.Method.Replace(Environment.NewLine, "");
+            string requestMethod = httpContext.Request.Method.Replace(Environment.NewLine, string.Empty);
             string requestUrl = httpContext.Request.GetEncodedUrl();
             LogMeasurement(requestMethod, requestUrl, Environment.NewLine, timingResults);
         }

src/JsonApiDotNetCore/Middleware/JsonApiMiddleware.cs

@@ -48,7 +48,7 @@ public override string ToString()
 
     public override string ToFullString()
     {
-        return $"{string.Join(',', Elements.Select(child => child.ToFullString()))}{(IsAutoGenerated ? " (auto-generated)" : "")}";
+        return $"{string.Join(',', Elements.Select(child => child.ToFullString()))}{(IsAutoGenerated ? " (auto-generated)" : string.Empty)}";
     }
 
     public override bool Equals(object? obj)