Profile EnableDetailedErrors

[smitpatel]

In tracking query statemanager would throw such exception. For non-tracking we just skip it and return null instead.

[smitpatel]

I investigated this. Tracking or not, we throw exception early while trying to read value.

Message: 
    System.Data.SqlTypes.SqlNullValueException : Data is Null. This method or property cannot be called on Null values.
  Stack Trace: 
    SqlBuffer.ThrowIfNull()
    SqlBuffer.get_String()
    SqlDataReader.GetString(Int32 i)
    lambda_method(Closure , DbDataReader , Int32[] )
    BufferedDataRecord.ReadObject(DbDataReader reader, Int32 ordinal, ReaderColumn column) line 1297
    BufferedDataRecord.ReadRow() line 897
    BufferedDataRecord.Initialize(DbDataReader reader, IReadOnlyList`1 columns) line 605
    BufferedDataReader.Initialize(IReadOnlyList`1 columns) line 117
    RelationalCommand.ExecuteReader(RelationalCommandParameterObject parameterObject) line 423
    Enumerator.InitializeReader(DbContext _, Boolean result) line 236
    ExecutionStrategy.ExecuteImplementation[TState,TResult](Func`3 operation, Func`3 verifySucceeded, TState state) line 173
    ExecutionStrategy.Execute[TState,TResult](TState state, Func`3 operation, Func`3 verifySucceeded) line 159
    Enumerator.MoveNext() line 185
    LargeArrayBuilder`1.AddRange(IEnumerable`1 items)
    EnumerableHelpers.ToArray[T](IEnumerable`1 source)
    Enumerable.ToArray[TSource](IEnumerable`1 source)
    FromSqlQueryTestBase`1.Key_entity_with_null_key_value() line 987

[AndriySvyryd]

We should wrap it in a better exception, at least indicating the column name

[smitpatel]

I guess it is time we uncomment this stuff?

efcore/src/EFCore.Relational/Query/RelationalShapedQueryCompilingExpressionVisitor.RelationalProjectionBindingRemovingExpressionVisitor.cs

Lines 224 to 251 in 2972c62

	//var exceptionParameter
	// = Expression.Parameter(typeof(Exception), name: "e");
	//var property = materializationInfo.Property;
	//if (detailedErrorsEnabled)
	//{
	// var catchBlock
	// = Expression
	// .Catch(
	// exceptionParameter,
	// Expression.Call(
	// _throwReadValueExceptionMethod
	// .MakeGenericMethod(valueExpression.Type),
	// exceptionParameter,
	// Expression.Call(
	// dataReaderExpression,
	// _getFieldValueMethod.MakeGenericMethod(typeof(object)),
	// indexExpression),
	// Expression.Constant(property, typeof(IPropertyBase))));
	// valueExpression = Expression.TryCatch(valueExpression, catchBlock);
	//}
	//if (box && valueExpression.Type.GetTypeInfo().IsValueType)
	//{
	// valueExpression = Expression.Convert(valueExpression, typeof(object));
	//}