From 83dc4e29dd1276775fdff5a80fdc6f72418435bc Mon Sep 17 00:00:00 2001
From: Laurents Meyer <laucomm@gmail.com>
Date: Mon, 4 Mar 2024 16:21:07 +0100
Subject: [PATCH] Add `DateTimeOffset` member translations for `.DateTime`,
 `.UtcDateTime` and `.LocalDateTime`.

---
 .../Internal/MySqlDateTimeMemberTranslator.cs | 22 ++++++++++++
 .../Query/GearsOfWarQueryMySqlTest.MySql.cs   | 34 +++++++++++++++++++
 .../Query/MySqlTimeZoneTest.cs                | 25 ++++++++++++++
 3 files changed, 81 insertions(+)

diff --git a/src/EFCore.MySql/Query/Internal/MySqlDateTimeMemberTranslator.cs b/src/EFCore.MySql/Query/Internal/MySqlDateTimeMemberTranslator.cs
index ececfd693..b8aedab82 100644
--- a/src/EFCore.MySql/Query/Internal/MySqlDateTimeMemberTranslator.cs
+++ b/src/EFCore.MySql/Query/Internal/MySqlDateTimeMemberTranslator.cs
@@ -8,6 +8,7 @@
 using Microsoft.EntityFrameworkCore.Diagnostics;
 using Microsoft.EntityFrameworkCore.Query;
 using Microsoft.EntityFrameworkCore.Query.SqlExpressions;
+using Pomelo.EntityFrameworkCore.MySql.Utilities;
 
 namespace Pomelo.EntityFrameworkCore.MySql.Query.Internal
 {
@@ -141,6 +142,27 @@ public virtual SqlExpression Translate(
                 }
             }
 
+            if (declaringType == typeof(DateTimeOffset))
+            {
+                switch (member.Name)
+                {
+                    case nameof(DateTimeOffset.DateTime):
+                    case nameof(DateTimeOffset.UtcDateTime):
+                        // We represent `DateTimeOffset` values as UTC datetime values in the database. Therefore, `DateTimeOffset`,
+                        // `DateTimeOffset.DateTime` and `DateTimeOffset.UtcDateTime` are all the same.
+                        return _sqlExpressionFactory.Convert(instance, typeof(DateTime));
+
+                    case nameof(DateTimeOffset.LocalDateTime):
+                        return _sqlExpressionFactory.NullableFunction(
+                            "CONVERT_TZ",
+                            [instance, _sqlExpressionFactory.Constant("+00:00"), _sqlExpressionFactory.Fragment("@@session.time_zone")],
+                            typeof(DateTime),
+                            null,
+                            false,
+                            Statics.GetTrueValues(3));
+                }
+            }
+
             return null;
         }
     }
diff --git a/test/EFCore.MySql.FunctionalTests/Query/GearsOfWarQueryMySqlTest.MySql.cs b/test/EFCore.MySql.FunctionalTests/Query/GearsOfWarQueryMySqlTest.MySql.cs
index 3214a3075..7a537a2cc 100644
--- a/test/EFCore.MySql.FunctionalTests/Query/GearsOfWarQueryMySqlTest.MySql.cs
+++ b/test/EFCore.MySql.FunctionalTests/Query/GearsOfWarQueryMySqlTest.MySql.cs
@@ -196,5 +196,39 @@ await AssertQuery(
 WHERE `w`.`IsAutomatic` = TRUE"), keys); // Breaking change in 5.0 due to bool expression optimization in `SqlNullabilityProcessor`.
                                          // Was "`w`.`IsAutomatic` <> FALSE" before.
         }
+
+        [ConditionalTheory]
+        [MemberData(nameof(IsAsyncData))]
+        public virtual async Task DateTimeOffset_DateTime(bool async)
+        {
+            await AssertQuery(
+                async,
+                ss => ss.Set<Mission>().Where(e => e.Timeline == e.Timeline.DateTime),
+                ss => ss.Set<Mission>().Where(e => true));
+
+            AssertSql(
+                """
+SELECT `m`.`Id`, `m`.`CodeName`, `m`.`Date`, `m`.`Duration`, `m`.`Rating`, `m`.`Time`, `m`.`Timeline`
+FROM `Missions` AS `m`
+WHERE `m`.`Timeline` = `m`.`Timeline`
+""");
+        }
+
+        [ConditionalTheory]
+        [MemberData(nameof(IsAsyncData))]
+        public virtual async Task DateTimeOffset_UtcDateTime(bool async)
+        {
+            await AssertQuery(
+                async,
+                ss => ss.Set<Mission>().Where(e => e.Timeline == e.Timeline.UtcDateTime),
+                ss => ss.Set<Mission>().Where(e => true));
+
+            AssertSql(
+                """
+SELECT `m`.`Id`, `m`.`CodeName`, `m`.`Date`, `m`.`Duration`, `m`.`Rating`, `m`.`Time`, `m`.`Timeline`
+FROM `Missions` AS `m`
+WHERE `m`.`Timeline` = `m`.`Timeline`
+""");
+        }
     }
 }
diff --git a/test/EFCore.MySql.Tests/Query/MySqlTimeZoneTest.cs b/test/EFCore.MySql.Tests/Query/MySqlTimeZoneTest.cs
index 13407882d..acc81ad52 100644
--- a/test/EFCore.MySql.Tests/Query/MySqlTimeZoneTest.cs
+++ b/test/EFCore.MySql.Tests/Query/MySqlTimeZoneTest.cs
@@ -52,6 +52,30 @@ LIMIT 2
                 Fixture.Sql);
         }
 
+        [ConditionalFact]
+        public void DateTimeOffset_LocalDateTime()
+        {
+            using var context = Fixture.CreateContext();
+            SetSessionTimeZone(context);
+            Fixture.ClearSql();
+
+            var metalContainer = context.Set<Model.Container>()
+                .Where(c => c.DeliveredDateTimeOffset.LocalDateTime == MySqlTimeZoneFixture.OriginalDateTimeUtc.AddHours(MySqlTimeZoneFixture.SessionOffset))
+                .Select(c => new { c.DeliveredDateTimeOffset.LocalDateTime })
+                .Single();
+
+            Assert.Equal(MySqlTimeZoneFixture.OriginalDateTimeUtc.AddHours(MySqlTimeZoneFixture.SessionOffset), metalContainer.LocalDateTime);
+
+            Assert.Equal(
+                """
+SELECT CONVERT_TZ(`c`.`DeliveredDateTimeOffset`, '+00:00', @@session.time_zone) AS `LocalDateTime`
+FROM `Container` AS `c`
+WHERE CONVERT_TZ(`c`.`DeliveredDateTimeOffset`, '+00:00', @@session.time_zone) = TIMESTAMP '2023-12-31 15:00:00'
+LIMIT 2
+""",
+                Fixture.Sql);
+        }
+
         private static void SetSessionTimeZone(MySqlTimeZoneFixture.MySqlTimeZoneContext context)
         {
             context.Database.OpenConnection();
@@ -63,6 +87,7 @@ private static void SetSessionTimeZone(MySqlTimeZoneFixture.MySqlTimeZoneContext
 
         public class MySqlTimeZoneFixture : MySqlTestFixtureBase<MySqlTimeZoneFixture.MySqlTimeZoneContext>
         {
+            public const int SessionOffset = -8; // UTC-8
             public const int OriginalOffset = 2; // UTC+2
             public static readonly DateTime OriginalDateTimeUtc = new DateTime(2023, 12, 31, 23, 0, 0);
             public static readonly DateTime OriginalDateTime = OriginalDateTimeUtc.AddHours(OriginalOffset);