Fix: dotnet#7048 - EF Core 1.1 .ToString() translation causes exception

Adding bad data error handling logic to materialization introduced the possibility of hitting a known expression compiler limitation (as described here: dotnet/corefx#13126). This change works around the limitation by moving the read-value try-catch to a helper method, thus we no longer insert a try-catch directly into the output ET.
davidMuir · Nov 21, 2016 · dd44082 · dd44082
1 parent 539c9e6
commit dd44082
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Showing 3 changed files with 64 additions and 28 deletions.
diff --git a/src/Microsoft.EntityFrameworkCore.Specification.Tests/GearsOfWarQueryTestBase.cs b/src/Microsoft.EntityFrameworkCore.Specification.Tests/GearsOfWarQueryTestBase.cs
@@ -44,6 +44,18 @@ public virtual void Include_multiple_one_to_one_and_one_to_many()
             }
         }
 
+        [ConditionalFact]
+        public virtual void ToString_guid_property_projection()
+        {
+            using (var context = CreateContext())
+            {
+                var query = context.Tags.Select(ct => new { A = ct.GearNickName, B = ct.Id.ToString() });
+                var result = query.ToList();
+
+                Assert.Equal(6, result.Count);
+            }
+        }
+
         [ConditionalFact]
         public virtual void Include_multiple_one_to_one_and_one_to_many_self_reference()
         {

diff --git a/src/Microsoft.EntityFrameworkCore/Metadata/Internal/EntityMaterializerSource.cs b/src/Microsoft.EntityFrameworkCore/Metadata/Internal/EntityMaterializerSource.cs
@@ -29,34 +29,42 @@ private static readonly MethodInfo _readValue
         ///     directly from your code. This API may change or be removed in future releases.
         /// </summary>
         public virtual Expression CreateReadValueExpression(
-            Expression valueBuffer,
-            Type type,
+                Expression valueBuffer,
+                Type type,
+                int index,
+                IProperty property = null)
+            => Expression.Call(
+                _tryReadValueMethod.MakeGenericMethod(type),
+                valueBuffer,
+                Expression.Constant(index),
+                Expression.Constant(property, typeof(IPropertyBase)));
+
+        private static readonly MethodInfo _tryReadValueMethod
+            = typeof(EntityMaterializerSource).GetTypeInfo()
+                .GetDeclaredMethod(nameof(TryReadValue));
+
+        private static TValue TryReadValue<TValue>(
+            ValueBuffer valueBuffer, 
             int index,
-            IProperty property = null)
+            IPropertyBase property = null)
         {
-            var readValueExpression
-                = Expression.Convert(CreateReadValueCallExpression(valueBuffer, index), type);
-
-            var exceptionParameter
-                = Expression.Parameter(typeof(Exception), "e");
-
-            var catchBlock
-                = Expression
-                    .Catch(exceptionParameter,
-                        Expression.Call(
-                            _createReadValueException.MakeGenericMethod(readValueExpression.Type),
-                            exceptionParameter,
-                            CreateReadValueCallExpression(valueBuffer, index),
-                            Expression.Constant(property, typeof(IPropertyBase))));
-
-            return Expression.TryCatch(readValueExpression, catchBlock);
-        }
+            object untypedValue = null;
 
-        private static readonly MethodInfo _createReadValueException
-            = typeof(EntityMaterializerSource).GetTypeInfo()
-                .GetDeclaredMethod(nameof(ThrowReadValueException));
+            try
+            {
+                untypedValue = valueBuffer[index];
 
-        private static TValue ThrowReadValueException<TValue>(
+                return (TValue)untypedValue;
+            }
+            catch (Exception e)
+            {
+                ThrowReadValueException<TValue>(e, untypedValue, property);
+            }
+
+            return default(TValue);
+        }
+
+        private static void ThrowReadValueException<TValue>(
             Exception exception, object value, IPropertyBase property = null)
         {
             var expectedType = typeof(TValue);

diff --git a/test/Microsoft.EntityFrameworkCore.SqlServer.FunctionalTests/QueryLoggingSqlServerTest.cs b/test/Microsoft.EntityFrameworkCore.SqlServer.FunctionalTests/QueryLoggingSqlServerTest.cs
@@ -131,10 +131,26 @@ ORDER BY [o].[CustomerID]
             materializer: (ValueBuffer valueBuffer) => 
             {
                 var3 = new Order()
-                var3.<OrderID>k__BackingField = try { (int) object valueBuffer.get_Item(0) } catch (Exception) { ... } 
-                var3.<CustomerID>k__BackingField = try { (string) object valueBuffer.get_Item(1) } catch (Exception) { ... } 
-                var3.<EmployeeID>k__BackingField = try { (Nullable<int>) object valueBuffer.get_Item(2) } catch (Exception) { ... } 
-                var3.<OrderDate>k__BackingField = try { (Nullable<DateTime>) object valueBuffer.get_Item(3) } catch (Exception) { ... } 
+                var3.<OrderID>k__BackingField = int TryReadValue(
+                    valueBuffer: valueBuffer, 
+                    index: 0, 
+                    property: OrderID
+                )
+                var3.<CustomerID>k__BackingField = string TryReadValue(
+                    valueBuffer: valueBuffer, 
+                    index: 1, 
+                    property: CustomerID
+                )
+                var3.<EmployeeID>k__BackingField = Nullable<int> TryReadValue(
+                    valueBuffer: valueBuffer, 
+                    index: 2, 
+                    property: EmployeeID
+                )
+                var3.<OrderDate>k__BackingField = Nullable<DateTime> TryReadValue(
+                    valueBuffer: valueBuffer, 
+                    index: 3, 
+                    property: OrderDate
+                )
                 return instance
             }
         )