Check offset when comparing DateTimeOffset (#24606)

Fixes #24567
dotnet · Apr 8, 2021 · ac2bb48 · ac2bb48
1 parent 784624e
commit ac2bb48
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Showing 3 changed files with 47 additions and 5 deletions.
diff --git a/src/EFCore/ChangeTracking/ValueComparer.cs b/src/EFCore/ChangeTracking/ValueComparer.cs
@@ -4,6 +4,7 @@
 using System;
 using System.Collections;
 using System.Collections.Generic;
+using System.Linq;
 using System.Linq.Expressions;
 using System.Reflection;
 using Microsoft.EntityFrameworkCore.Query;
@@ -205,13 +206,17 @@ public static ValueComparer CreateDefault(Type type, bool favorStructuralCompari
                 return new DefaultFloatValueComparer(favorStructuralComparisons);
             }
 
+            if (nonNullabletype == typeof(DateTimeOffset))
+            {
+                return new DefaultDateTimeOffsetValueComparer(favorStructuralComparisons);
+            }
+
             var comparerType = nonNullabletype.IsInteger()
                 || nonNullabletype == typeof(decimal)
                 || nonNullabletype == typeof(bool)
                 || nonNullabletype == typeof(string)
                 || nonNullabletype == typeof(DateTime)
                 || nonNullabletype == typeof(Guid)
-                || nonNullabletype == typeof(DateTimeOffset)
                 || nonNullabletype == typeof(TimeSpan)
                     ? typeof(DefaultValueComparer<>)
                     : typeof(ValueComparer<>);
@@ -228,6 +233,14 @@ public DefaultValueComparer(bool favorStructuralComparisons)
             {
             }
 
+            public DefaultValueComparer(Expression<Func<T?, T?, bool>> equalsExpression, bool favorStructuralComparisons)
+                : base(
+                    equalsExpression,
+                    CreateDefaultHashCodeExpression(favorStructuralComparisons),
+                    CreateDefaultSnapshotExpression(favorStructuralComparisons))
+            {
+            }
+
             public override Expression ExtractEqualsBody(Expression leftExpression, Expression rightExpression)
                 => Expression.Equal(leftExpression, rightExpression);
 
@@ -244,7 +257,7 @@ public override Expression ExtractSnapshotBody(Expression expression)
         internal sealed class DefaultDoubleValueComparer : DefaultValueComparer<double>
         {
             public DefaultDoubleValueComparer(bool favorStructuralComparisons)
-                : base(favorStructuralComparisons)
+                : base((v1, v2) => v1.Equals(v2), favorStructuralComparisons)
             {
             }
 
@@ -255,12 +268,31 @@ public override Expression ExtractEqualsBody(Expression leftExpression, Expressi
         internal sealed class DefaultFloatValueComparer : DefaultValueComparer<float>
         {
             public DefaultFloatValueComparer(bool favorStructuralComparisons)
-                : base(favorStructuralComparisons)
+                : base((v1, v2) => v1.Equals(v2), favorStructuralComparisons)
             {
             }
 
             public override Expression ExtractEqualsBody(Expression leftExpression, Expression rightExpression)
                 => Expression.Call(leftExpression, _floatEqualsMethodInfo, rightExpression);
         }
+
+        internal sealed class DefaultDateTimeOffsetValueComparer : DefaultValueComparer<DateTimeOffset>
+        {
+            private static readonly PropertyInfo _offsetPropertyInfo = typeof(DateTimeOffset).GetProperty(nameof(DateTimeOffset.Offset))!;
+
+            // In .NET, two DateTimeOffset instances are considered equal if they represent the same point in time but with different
+            // time zone offsets. This comparer considers such DateTimeOffset as non-equal.
+            public DefaultDateTimeOffsetValueComparer(bool favorStructuralComparisons)
+                : base((v1, v2) => v1 == v2 && v1.Offset == v2.Offset, favorStructuralComparisons)
+            {
+            }
+
+            public override Expression ExtractEqualsBody(Expression leftExpression, Expression rightExpression)
+                => Expression.And(
+                    Expression.Equal(leftExpression, rightExpression),
+                    Expression.Equal(
+                        Expression.Property(leftExpression, _offsetPropertyInfo),
+                        Expression.Property(rightExpression, _offsetPropertyInfo)));
+        }
     }
 }
diff --git a/test/EFCore.Relational.Tests/Storage/RelationalTypeMappingTest.cs b/test/EFCore.Relational.Tests/Storage/RelationalTypeMappingTest.cs
@@ -551,6 +551,16 @@ public virtual void Float_value_comparer_handles_NaN()
             Assert.False(typeMapping.Comparer.Equals(3.0f, float.NaN));
         }
 
+        [ConditionalFact]
+        public virtual void DateTimeOffset_value_comparer_handles_different_offsets()
+        {
+            var typeMapping = new DateTimeOffsetTypeMapping("datetimeoffset", DbType.DateTimeOffset);
+
+            Assert.False(typeMapping.Comparer.Equals(
+                new DateTimeOffset(2000, 1, 1, 12, 0, 0, TimeSpan.FromHours(0)),
+                new DateTimeOffset(2000, 1, 1, 13, 0, 0, TimeSpan.FromHours(1))));
+        }
+
         [ConditionalFact]
         public virtual void Primary_key_type_mapping_is_picked_up_by_FK_without_going_through_store_type()
         {

diff --git a/test/EFCore.Specification.Tests/BuiltInDataTypesTestBase.cs b/test/EFCore.Specification.Tests/BuiltInDataTypesTestBase.cs
@@ -261,7 +261,7 @@ private void QueryBuiltInDataTypesTest<TEntity>(EntityEntry<TEntity> source)
 
             if (entityType.FindProperty(nameof(BuiltInDataTypes.TestDateTimeOffset)) != null)
             {
-                var param7 = new DateTimeOffset(new DateTime(), TimeSpan.FromHours(-8.0));
+                var param7 = new DateTimeOffset(new DateTime(), TimeSpan.Zero);
                 Assert.Same(
                     entity,
                     set.Where(e => e.Id == 11 && EF.Property<DateTimeOffset>(e, nameof(BuiltInDataTypes.TestDateTimeOffset)) == param7)
@@ -495,7 +495,7 @@ protected EntityEntry<TEntity> AddTestBuiltInDataTypes<TEntity>(DbSet<TEntity> s
                     TestDouble = -1.23456789,
                     TestDecimal = -1234567890.01M,
                     TestDateTime = Fixture.DefaultDateTime,
-                    TestDateTimeOffset = new DateTimeOffset(new DateTime(), TimeSpan.FromHours(-8.0)),
+                    TestDateTimeOffset = new DateTimeOffset(new DateTime(), TimeSpan.Zero),
                     TestTimeSpan = new TimeSpan(0, 10, 9, 8, 7),
                     TestSingle = -1.234F,
                     TestBoolean = true,