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System.InvalidOperationException: 'An exception occurred while reading a database value. The expected type was 'System.Int32' but the actual value was of type 'System.Int16'.'

See original GitHub issue

The following Linq query generates the titled exception.

from e in es
join d in ds on e.Id equals d.EmployeeId into x
from j in x.DefaultIfEmpty()
select new Holder
{
      Name = e.Name,
      DeviceId = j.DeviceId //(short?)
}

es and ds are DbSets. DeviceId is type of int?. j.DeviceId is type of short.

If we remove DefaultIfEmpty(), then we don’t get the exception.

Please refer to the Steps to reproduce for complete source code.

Exception message:

System.InvalidOperationException: 'An exception occurred while reading a database value. The expected type was 'System.Int32' but the actual value was of type 'System.Int16'.'

Stack trace:

   at Microsoft.EntityFrameworkCore.Metadata.Internal.EntityMaterializerSource.ThrowReadValueException[TValue](Exception exception, Object value, IPropertyBase property)
   at Microsoft.EntityFrameworkCore.Storage.Internal.TypedRelationalValueBufferFactory.Create(DbDataReader dataReader)
   at Microsoft.EntityFrameworkCore.Query.Internal.QueryingEnumerable`1.Enumerator.BufferlessMoveNext(DbContext _, Boolean buffer)
   at Microsoft.EntityFrameworkCore.Storage.Internal.NoopExecutionStrategy.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..ctor(IEnumerable`1 collection)
   at System.Linq.Enumerable.ToList[TSource](IEnumerable`1 source)
   at TestHostForCastException.Program.Main(String[] args) in C:\EFCoreTestBed\Program.cs:line 23

Inner Exception 1:
InvalidCastException: Specified cast is not valid.