Reference types returns null instead of throwing for empty collections

Author: henriquewr

src/EFCore/Query/Internal/QueryableMethodNormalizingExpressionVisitor.cs

@@ -776,7 +776,7 @@ private MethodCallExpression TryNormalizeMaxByMinBy(MethodCallExpression methodC
 
             var keySelector = methodCallExpression.Arguments[1].UnwrapLambdaFromQuote();
 
-            var firstMethod = sourceType.IsNullableValueType()
+            var firstMethod = sourceType.IsNullableType()
                 ? QueryableMethods.FirstOrDefaultWithoutPredicate
                 : QueryableMethods.FirstWithoutPredicate;
 

test/EFCore.Cosmos.FunctionalTests/Query/NorthwindAggregateOperatorsQueryCosmosTest.cs

@@ -707,6 +707,24 @@ OFFSET 0 LIMIT 1
         }
     }
 
+    public override async Task MaxBy_no_data_reference_type_source(bool async)
+    {
+        // Always throws for sync.
+        if (async)
+        {
+            await base.MaxBy_no_data_reference_type_source(async);
+
+AssertSql(
+"""
+SELECT VALUE c
+FROM root c
+WHERE ((c["$type"] = "Product") AND (c["SupplierID"] = -1))
+ORDER BY c["ProductID"] DESC
+OFFSET 0 LIMIT 1
+""");
+        }
+    }
+
     public override async Task MaxBy_no_data_cast_to_nullable(bool async)
     {
         // Always throws for sync.
@@ -896,6 +914,24 @@ OFFSET 0 LIMIT 1
         }
     }
 
+    public override async Task MinBy_no_data_reference_type_source(bool async)
+    {
+        // Always throws for sync.
+        if (async)
+        {
+            await base.MinBy_no_data_reference_type_source(async);
+
+            AssertSql(
+    """
+    SELECT VALUE c
+    FROM root c
+    WHERE ((c["$type"] = "Product") AND (c["SupplierID"] = -1))
+    ORDER BY c["ProductID"]
+    OFFSET 0 LIMIT 1
+    """);
+        }
+    }
+
     public override async Task MinBy_no_data_cast_to_nullable(bool async)
     {
         // Always throws for sync.

test/EFCore.Specification.Tests/Query/NorthwindAggregateOperatorsQueryTestBase.cs

@@ -356,6 +356,13 @@ public virtual Task MinBy_no_data_nullable_source(bool async)
             ss => ss.Set<Product>().Where(o => o.SupplierID == -1).Select(o => o.SupplierID),
             selector: o => o ?? 0 /*non nullable selector*/);
 
+    [ConditionalTheory, MemberData(nameof(IsAsyncData))]
+    public virtual Task MinBy_no_data_reference_type_source(bool async)
+        => AssertMinBy(
+            async,
+            ss => ss.Set<Product>().Where(o => o.SupplierID == -1),
+            selector: o => o.ProductID);
+
     [ConditionalTheory, MemberData(nameof(IsAsyncData))]
     public virtual Task MinBy_no_data_cast_to_nullable(bool async)
         => Assert.ThrowsAsync<InvalidOperationException>(() => AssertMinBy(
@@ -417,6 +424,13 @@ public virtual Task MaxBy_no_data_nullable_source(bool async)
             ss => ss.Set<Product>().Where(o => o.SupplierID == -1).Select(o => o.SupplierID),
             selector: o => o ?? 0 /*non nullable selector*/);
 
+    [ConditionalTheory, MemberData(nameof(IsAsyncData))]
+    public virtual Task MaxBy_no_data_reference_type_source(bool async)
+        => AssertMaxBy(
+            async,
+            ss => ss.Set<Product>().Where(o => o.SupplierID == -1),
+            selector: o => o.ProductID);
+
     [ConditionalTheory, MemberData(nameof(IsAsyncData))]
     public virtual Task MaxBy_no_data_cast_to_nullable(bool async)
         => Assert.ThrowsAsync<InvalidOperationException>(() => AssertMaxBy(

test/EFCore.Specification.Tests/TestUtilities/ExpectedQueryRewritingVisitor.cs

@@ -213,7 +213,7 @@ private static Expression RewriteMaxByMinBy(MethodCallExpression methodCallExpre
 
         if (methodCallExpression.Method.DeclaringType == typeof(Enumerable))
         {
-            firstMethod = sourceType.IsNullableValueType()
+            firstMethod = sourceType.IsNullableType()
                 ? EnumerableMethods.FirstOrDefaultWithoutPredicate
                 : EnumerableMethods.FirstWithoutPredicate;
 
@@ -225,7 +225,7 @@ private static Expression RewriteMaxByMinBy(MethodCallExpression methodCallExpre
         }
         else
         {
-            firstMethod = sourceType.IsNullableValueType()
+            firstMethod = sourceType.IsNullableType()
                 ? QueryableMethods.FirstOrDefaultWithoutPredicate
                 : QueryableMethods.FirstWithoutPredicate;
 

test/EFCore.SqlServer.FunctionalTests/Query/NorthwindAggregateOperatorsQuerySqlServerTest.cs

@@ -389,6 +389,19 @@ ORDER BY COALESCE([p].[SupplierID], 0)
 """);
     }
 
+    public override async Task MinBy_no_data_reference_type_source(bool async)
+    {
+        await base.MinBy_no_data_reference_type_source(async);
+
+        AssertSql(
+"""
+SELECT TOP(1) [p].[ProductID], [p].[Discontinued], [p].[ProductName], [p].[SupplierID], [p].[UnitPrice], [p].[UnitsInStock]
+FROM [Products] AS [p]
+WHERE [p].[SupplierID] = -1
+ORDER BY [p].[ProductID]
+""");
+    }
+
     public override async Task MinBy_no_data_cast_to_nullable(bool async)
     {
         await base.MinBy_no_data_cast_to_nullable(async);
@@ -590,6 +603,19 @@ ORDER BY COALESCE([p].[SupplierID], 0) DESC
 """);
     }
 
+    public override async Task MaxBy_no_data_reference_type_source(bool async)
+    {
+        await base.MaxBy_no_data_reference_type_source(async);
+
+        AssertSql(
+"""
+SELECT TOP(1) [p].[ProductID], [p].[Discontinued], [p].[ProductName], [p].[SupplierID], [p].[UnitPrice], [p].[UnitsInStock]
+FROM [Products] AS [p]
+WHERE [p].[SupplierID] = -1
+ORDER BY [p].[ProductID] DESC
+""");
+    }
+
     public override async Task MaxBy_no_data_cast_to_nullable(bool async)
     {
         await base.MaxBy_no_data_cast_to_nullable(async);