Null checking in anonymous projection

[peterjanto]

Exception message: System.InvalidOperationException: 'No mapping to a relational type can be found for the CLR type 'Expression[]'.'
Stack trace:
   at Microsoft.EntityFrameworkCore.Storage.RelationalTypeMappingSourceExtensions.GetMapping(IRelationalTypeMappingSource typeMappingSource, Type clrType)
   at Microsoft.EntityFrameworkCore.Query.Sql.DefaultQuerySqlGenerator.GenerateSqlLiteral(Object value)
   at Microsoft.EntityFrameworkCore.Query.Sql.DefaultQuerySqlGenerator.VisitConstant(ConstantExpression constantExpression)
   at System.Linq.Expressions.ConstantExpression.Accept(ExpressionVisitor visitor)
   at Microsoft.EntityFrameworkCore.Query.Sql.DefaultQuerySqlGenerator.VisitAlias(AliasExpression aliasExpression)
   at Microsoft.EntityFrameworkCore.SqlServer.Query.Sql.Internal.SqlServerQuerySqlGenerator.GenerateProjection(Expression projection)
   at Microsoft.EntityFrameworkCore.Query.Sql.DefaultQuerySqlGenerator.GenerateList[T](IReadOnlyList`1 items, Action`1 generationAction, Action`1 joinAction)
   at Microsoft.EntityFrameworkCore.Query.Sql.DefaultQuerySqlGenerator.VisitSelect(SelectExpression selectExpression)
   at Microsoft.EntityFrameworkCore.Query.Sql.DefaultQuerySqlGenerator.GenerateSql(IReadOnlyDictionary`2 parameterValues)
   at Microsoft.EntityFrameworkCore.Query.Internal.ShaperCommandContext.GetRelationalCommand(IReadOnlyDictionary`2 parameters)
   at Microsoft.EntityFrameworkCore.Query.Internal.QueryingEnumerable`1.Enumerator.BufferlessMoveNext(DbContext _, Boolean buffer)
   at Microsoft.EntityFrameworkCore.SqlServer.Storage.Internal.SqlServerExecutionStrategy.Execute[TState,TResult](TState state, Func`3 operation, Func`3 verifySucceeded)
   at Microsoft.EntityFrameworkCore.Query.Internal.QueryingEnumerable`1.Enumerator.MoveNext()
   at Microsoft.EntityFrameworkCore.Query.Internal.QueryBuffer.CorrelateSubquery[TInner,TOut,TCollection](Int32 correlatedCollectionId, INavigation navigation, Func`2 resultCollectionFactory, MaterializedAnonymousObject& outerKey, Boolean tracking, Func`1 correlatedCollectionFactory, Func`3 correlationPredicate)
   at lambda_method(Closure , QueryContext , ValueBuffer )
   at Microsoft.EntityFrameworkCore.Query.ExpressionVisitors.Internal.ProjectionShaper.TypedProjectionShaper`3.Shape(QueryContext queryContext, ValueBuffer& valueBuffer)
   at Microsoft.EntityFrameworkCore.Query.Internal.QueryingEnumerable`1.Enumerator.BufferlessMoveNext(DbContext _, Boolean buffer)
   at Microsoft.EntityFrameworkCore.SqlServer.Storage.Internal.SqlServerExecutionStrategy.Execute[TState,TResult](TState state, Func`3 operation, Func`3 verifySucceeded)
   at Microsoft.EntityFrameworkCore.Query.Internal.QueryingEnumerable`1.Enumerator.MoveNext()
   at Microsoft.EntityFrameworkCore.Query.Internal.LinqOperatorProvider.ExceptionInterceptor`1.EnumeratorExceptionInterceptor.MoveNext()
   at System.Collections.Generic.List`1.AddEnumerable(IEnumerable`1 enumerable)
   at System.Linq.Enumerable.ToList[TSource](IEnumerable`1 source)
   at xxxx

Steps to reproduce

public class Partner
{
   public ICollection<Address> Addresses { get; set; }
}

public class Address
{
  public AddressTurnovers Turnovers { get; set; }
}

public class AddressTurnovers
{
   public decimal AmountIn { get; set; }
}

var partners = apiContext.Partners
                .Select(x => new
                {
                    Addresses = x.Addresses.Select(y => new
                    {
                        Turnovers = y.Turnovers == null ? null : new
                        {
                            y.Turnovers.AmountIn
                        },
                    }).ToList()
                }).ToList();

Further technical details

EF Core version: 2.1.1
Database Provider: Microsoft.EntityFrameworkCore.SqlServer 2.1.1
Operating system: WIN10
IDE: Visual Studio 2017 15.7.1

[smitpatel]

@peterjanto - Thanks for the repro.

[ajcvickers]

@smitpatel This issue is approved for patch and the release\2.1 branch is now open for merging. Please ensure:

• The appropriate changes get into both the release and dev branches
• Quirking is included for the release branch only

[smitpatel]

Patch fix commit 2821a22
Quirk commit 6106628
dev commit 443d4ec

[peterjanto]

Hello, Thanks for fix ! But when i use something like this

modelBuilder.Entity<Address>().OwnsOne(x => x.Turnovers);

EF core throw this exception:

System.InvalidOperationException
  HResult=0x80131509
  Message=No mapping to a relational type can be found for the CLR type 'object'.
  Source=Microsoft.EntityFrameworkCore.Relational
  StackTrace:
   at Microsoft.EntityFrameworkCore.Storage.RelationalTypeMappingSourceExtensions.GetMapping(IRelationalTypeMappingSource typeMappingSource, Type clrType)
   at Microsoft.EntityFrameworkCore.Storage.TypeMaterializationInfo..ctor(Type modelClrType, IProperty property, IRelationalTypeMappingSource typeMappingSource, Int32 index)
   at Microsoft.EntityFrameworkCore.Query.Expressions.SelectExpression.<GetMappedProjectionTypes>b__69_0(Expression e)
   at System.Linq.Enumerable.SelectListIterator`2.MoveNext()
   at Microsoft.EntityFrameworkCore.Query.Expressions.SelectExpression.<GetMappedProjectionTypes>d__69.MoveNext()
   at System.Collections.Generic.LargeArrayBuilder`1.AddRange(IEnumerable`1 items)
   at System.Collections.Generic.EnumerableHelpers.ToArray[T](IEnumerable`1 source)
   at System.Linq.Enumerable.ToArray[TSource](IEnumerable`1 source)
   at Microsoft.EntityFrameworkCore.Query.Sql.DefaultQuerySqlGenerator.CreateValueBufferFactory(IRelationalValueBufferFactoryFactory relationalValueBufferFactoryFactory, DbDataReader dataReader)
   at Microsoft.EntityFrameworkCore.Internal.NonCapturingLazyInitializer.EnsureInitialized[TParam,TValue](TValue& target, TParam param, Func`2 valueFactory)
   at Microsoft.EntityFrameworkCore.Query.Internal.ShaperCommandContext.NotifyReaderCreated(DbDataReader dataReader)
   at Microsoft.EntityFrameworkCore.Query.Internal.QueryingEnumerable`1.Enumerator.BufferlessMoveNext(DbContext _, Boolean buffer)
   at Microsoft.EntityFrameworkCore.SqlServer.Storage.Internal.SqlServerExecutionStrategy.Execute[TState,TResult](TState state, Func`3 operation, Func`3 verifySucceeded)
   at Microsoft.EntityFrameworkCore.Query.Internal.QueryingEnumerable`1.Enumerator.MoveNext()
   at Microsoft.EntityFrameworkCore.Query.Internal.QueryBuffer.CorrelateSubquery[TInner,TOut,TCollection](Int32 correlatedCollectionId, INavigation navigation, Func`2 resultCollectionFactory, MaterializedAnonymousObject& outerKey, Boolean tracking, Func`1 correlatedCollectionFactory, Func`3 correlationPredicate)
   at Microsoft.EntityFrameworkCore.Query.ExpressionVisitors.Internal.ProjectionShaper.TypedProjectionShaper`3.Shape(QueryContext queryContext, ValueBuffer& valueBuffer)
   at Microsoft.EntityFrameworkCore.Query.Internal.QueryingEnumerable`1.Enumerator.BufferlessMoveNext(DbContext _, Boolean buffer)
   at Microsoft.EntityFrameworkCore.SqlServer.Storage.Internal.SqlServerExecutionStrategy.Execute[TState,TResult](TState state, Func`3 operation, Func`3 verifySucceeded)
   at Microsoft.EntityFrameworkCore.Query.Internal.QueryingEnumerable`1.Enumerator.MoveNext()
   at Microsoft.EntityFrameworkCore.Query.Internal.LinqOperatorProvider.ExceptionInterceptor`1.EnumeratorExceptionInterceptor.MoveNext()
   at System.Collections.Generic.List`1.AddEnumerable(IEnumerable`1 enumerable)
   at System.Linq.Enumerable.ToList[TSource](IEnumerable`1 source)
   at xxx

Further technical details

EF Core version: 2.1.2
Database Provider: Microsoft.EntityFrameworkCore.SqlServer 2.1.2
Operating system: WIN10
IDE: Visual Studio 2017 15.8.1

[smitpatel]

This is the SQL which fails

      SELECT [x.Posts].[Id], [x.Posts].[PostTurnOver_Value], [t].[Id], NULL, [x.Posts].[PostTurnOver_Value] AS [Value], [x.Posts].[BlogId]
      FROM [Posts] AS [x.Posts]
      INNER JOIN (
          SELECT [x0].[Id]
          FROM [Blogs] AS [x0]
      ) AS [t] ON [x.Posts].[BlogId] = [t].[Id]
      ORDER BY [t].[Id]

The issue is NULL for which we cannot find mapping.

[ajcvickers]

@smitpatel to file a new issue.

[smitpatel]

Filed #13157