Fix nullability warnings produced by .NET 6 with EF Core 6

Author: Bart Koelman

src/JsonApiDotNetCore/Configuration/InverseNavigationResolver.cs

@@ -38,7 +38,7 @@ private void Resolve(DbContext dbContext)
         {
             foreach (ResourceType resourceType in _resourceGraph.GetResourceTypes().Where(resourceType => resourceType.Relationships.Any()))
             {
-                IEntityType entityType = dbContext.Model.FindEntityType(resourceType.ClrType);
+                IEntityType? entityType = dbContext.Model.FindEntityType(resourceType.ClrType);
 
                 if (entityType != null)
                 {

src/JsonApiDotNetCore/Middleware/JsonApiMiddleware.cs

@@ -134,7 +134,7 @@ private async Task<bool> ValidateIfMatchHeaderAsync(HttpContext httpContext, Jso
         private static async Task<bool> ValidateContentTypeHeaderAsync(string allowedContentType, HttpContext httpContext,
             JsonSerializerOptions serializerOptions)
         {
-            string contentType = httpContext.Request.ContentType;
+            string? contentType = httpContext.Request.ContentType;
 
             // ReSharper disable once ConditionIsAlwaysTrueOrFalse
             // Justification: Workaround for https://github.com/dotnet/aspnetcore/issues/32097 (fixed in .NET 6)

src/JsonApiDotNetCore/Queries/Internal/QueryableBuilding/SelectClauseBuilder.cs

@@ -109,7 +109,7 @@ private ICollection<PropertySelector> ToPropertySelectors(IDictionary<ResourceFi
 
                 foreach (IProperty entityProperty in entityProperties)
                 {
-                    var propertySelector = new PropertySelector(entityProperty.PropertyInfo);
+                    var propertySelector = new PropertySelector(entityProperty.PropertyInfo!);
 
                     if (propertySelector.Property.SetMethod != null)
                     {

src/JsonApiDotNetCore/Repositories/EntityFrameworkCoreRepository.cs

@@ -379,7 +379,7 @@ private bool RequiresLoadOfRelationshipForDeletion(RelationshipAttribute relatio
 
         private INavigation? GetNavigation(RelationshipAttribute relationship)
         {
-            IEntityType entityType = _dbContext.Model.FindEntityType(typeof(TResource));
+            IEntityType? entityType = _dbContext.Model.FindEntityType(typeof(TResource));
             return entityType?.FindNavigation(relationship.Property.Name);
         }
 

src/JsonApiDotNetCore/Serialization/Response/LinkBuilder.cs

@@ -257,7 +257,7 @@ private bool ShouldIncludeResourceLink(LinkTypes linkType, ResourceType resource
             return _options.ResourceLinks.HasFlag(linkType);
         }
 
-        private string GetLinkForResourceSelf(ResourceType resourceType, string resourceId)
+        private string? GetLinkForResourceSelf(ResourceType resourceType, string resourceId)
         {
             string? controllerName = _controllerResourceMapping.GetControllerNameForResourceType(resourceType);
             IDictionary<string, object?> routeValues = GetRouteValues(resourceId, null);
@@ -286,15 +286,15 @@ private string GetLinkForResourceSelf(ResourceType resourceType, string resource
             return links.HasValue() ? links : null;
         }
 
-        private string GetLinkForRelationshipSelf(string leftId, RelationshipAttribute relationship)
+        private string? GetLinkForRelationshipSelf(string leftId, RelationshipAttribute relationship)
         {
             string? controllerName = _controllerResourceMapping.GetControllerNameForResourceType(relationship.LeftType);
             IDictionary<string, object?> routeValues = GetRouteValues(leftId, relationship.PublicName);
 
             return RenderLinkForAction(controllerName, GetRelationshipControllerActionName, routeValues);
         }
 
-        private string GetLinkForRelationshipRelated(string leftId, RelationshipAttribute relationship)
+        private string? GetLinkForRelationshipRelated(string leftId, RelationshipAttribute relationship)
         {
             string? controllerName = _controllerResourceMapping.GetControllerNameForResourceType(relationship.LeftType);
             IDictionary<string, object?> routeValues = GetRouteValues(leftId, relationship.PublicName);
@@ -315,11 +315,11 @@ private string GetLinkForRelationshipRelated(string leftId, RelationshipAttribut
             return routeValues;
         }
 
-        protected virtual string RenderLinkForAction(string? controllerName, string actionName, IDictionary<string, object?> routeValues)
+        protected virtual string? RenderLinkForAction(string? controllerName, string actionName, IDictionary<string, object?> routeValues)
         {
             return _options.UseRelativeLinks
-                ? _linkGenerator.GetPathByAction(_httpContextAccessor.HttpContext, actionName, controllerName, routeValues)
-                : _linkGenerator.GetUriByAction(_httpContextAccessor.HttpContext, actionName, controllerName, routeValues);
+                ? _linkGenerator.GetPathByAction(HttpContext, actionName, controllerName, routeValues)
+                : _linkGenerator.GetUriByAction(HttpContext, actionName, controllerName, routeValues);
         }
 
         /// <summary>

test/JsonApiDotNetCoreTests/IntegrationTests/Archiving/TelevisionBroadcastDefinition.cs

@@ -13,7 +13,7 @@
 using JsonApiDotNetCore.Resources;
 using JsonApiDotNetCore.Resources.Annotations;
 using JsonApiDotNetCore.Serialization.Objects;
-using Microsoft.EntityFrameworkCore;
+using TestBuildingBlocks;
 
 namespace JsonApiDotNetCoreTests.IntegrationTests.Archiving
 {
@@ -134,8 +134,7 @@ public override async Task OnWritingAsync(TelevisionBroadcast broadcast, WriteOp
             }
             else if (writeOperation == WriteOperationKind.DeleteResource)
             {
-                TelevisionBroadcast broadcastToDelete =
-                    await _dbContext.Broadcasts.FirstOrDefaultAsync(resource => resource.Id == broadcast.Id, cancellationToken);
+                TelevisionBroadcast? broadcastToDelete = await _dbContext.Broadcasts.FirstWithIdAsync(broadcast.Id, cancellationToken);
 
                 if (broadcastToDelete != null)
                 {

test/JsonApiDotNetCoreTests/IntegrationTests/AtomicOperations/Transactions/LyricRepository.cs

@@ -13,7 +13,7 @@ public sealed class LyricRepository : EntityFrameworkCoreRepository<Lyric, long>
     {
         private readonly ExtraDbContext _extraDbContext;
 
-        public override string TransactionId => _extraDbContext.Database.CurrentTransaction.TransactionId.ToString();
+        public override string? TransactionId => _extraDbContext.Database.CurrentTransaction?.TransactionId.ToString();
 
         public LyricRepository(ExtraDbContext extraDbContext, ITargetedFields targetedFields, IDbContextResolver dbContextResolver,
             IResourceGraph resourceGraph, IResourceFactory resourceFactory, IEnumerable<IQueryConstraintProvider> constraintProviders,

test/JsonApiDotNetCoreTests/IntegrationTests/CompositeKeys/CompositeKeyTests.cs

@@ -186,7 +186,8 @@ await _testContext.RunOnDatabaseAsync(async dbContext =>
 
             await _testContext.RunOnDatabaseAsync(async dbContext =>
             {
-                Car carInDatabase = await dbContext.Cars.FirstOrDefaultAsync(car => car.RegionId == newCar.RegionId && car.LicensePlate == newCar.LicensePlate);
+                Car? carInDatabase =
+                    await dbContext.Cars.FirstOrDefaultAsync(car => car.RegionId == newCar.RegionId && car.LicensePlate == newCar.LicensePlate);
 
                 carInDatabase.ShouldNotBeNull();
                 carInDatabase.Id.Should().Be($"{newCar.RegionId}:{newCar.LicensePlate}");
@@ -508,7 +509,7 @@ await _testContext.RunOnDatabaseAsync(async dbContext =>
 
             await _testContext.RunOnDatabaseAsync(async dbContext =>
             {
-                Car carInDatabase =
+                Car? carInDatabase =
                     await dbContext.Cars.FirstOrDefaultAsync(car => car.RegionId == existingCar.RegionId && car.LicensePlate == existingCar.LicensePlate);
 
                 carInDatabase.Should().BeNull();

test/JsonApiDotNetCoreTests/UnitTests/Links/LinkInclusionTests.cs

@@ -412,7 +412,7 @@ public override string GetUriByAddress<TAddress>(HttpContext httpContext, TAddre
                 return "https://domain.com/some/path";
             }
 
-            public override string GetUriByAddress<TAddress>(TAddress address, RouteValueDictionary values, string scheme, HostString host,
+            public override string GetUriByAddress<TAddress>(TAddress address, RouteValueDictionary values, string? scheme, HostString host,
                 PathString pathBase = new(), FragmentString fragment = new(), LinkOptions? options = null)
             {
                 throw new NotImplementedException();

test/TestBuildingBlocks/DbContextExtensions.cs

@@ -38,14 +38,14 @@ private static async Task ClearTablesAsync(this DbContext dbContext, params Type
         {
             foreach (Type model in models)
             {
-                IEntityType entityType = dbContext.Model.FindEntityType(model);
+                IEntityType? entityType = dbContext.Model.FindEntityType(model);
 
                 if (entityType == null)
                 {
                     throw new InvalidOperationException($"Table for '{model.Name}' not found.");
                 }
 
-                string tableName = entityType.GetTableName();
+                string tableName = entityType.GetTableName()!;
 
                 // PERF: We first try to clear the table, which is fast and usually succeeds, unless foreign key constraints are violated.
                 // In that case, we recursively delete all related data, which is slow.