[release/6.0] Query: Don't add DbParameter if already added

src/EFCore.Relational/Storage/Internal/RawRelationalParameter.cs

@@ -58,11 +58,19 @@ public override void AddDbParameter(DbCommand command, object? value)
                 value is DbParameter,
                 $"{nameof(value)} isn't a DbParameter in {nameof(RawRelationalParameter)}.{nameof(AddDbParameter)}");
 
-            if (value is DbParameter dbParameter
-                && dbParameter.Direction == ParameterDirection.Input
-                && value is ICloneable cloneable)
+            if (value is DbParameter dbParameter)
             {
-                value = cloneable.Clone();
+                if (!(AppContext.TryGetSwitch("Microsoft.EntityFrameworkCore.Issue27427", out var enabled) && enabled)
+                    && command.Parameters.Contains(dbParameter.ParameterName))
+                {
+                    return;
+                }
+
+                if (dbParameter.Direction == ParameterDirection.Input
+                    && value is ICloneable cloneable)
+                {
+                    value = cloneable.Clone();
+                }
             }
 
             command.Parameters.Add(value);

test/EFCore.Relational.Specification.Tests/Query/FromSqlQueryTestBase.cs

@@ -1502,6 +1502,25 @@ public virtual async Task FromSqlRaw_with_dbParameter_mixed_in_subquery(bool asy
             Assert.Equal(26, actual.Length);
         }
 
+        [ConditionalTheory]
+        [MemberData(nameof(IsAsyncData))]
+        public virtual async Task Multiple_occurrences_of_FromSql_with_db_parameter_adds_parameter_only_once(bool async)
+        {
+            using var context = CreateContext();
+            var city = "Seattle";
+            var fromSqlQuery = context.Customers.FromSqlRaw(
+                NormalizeDelimitersInRawString(@"SELECT * FROM [Customers] WHERE [City] = {0}"),
+                                CreateDbParameter("city", city));
+
+            var query = fromSqlQuery.Intersect(fromSqlQuery);
+
+            var actual = async
+                ? await query.ToArrayAsync()
+                : query.ToArray();
+
+            Assert.Single(actual);
+        }
+
         protected string NormalizeDelimitersInRawString(string sql)
             => Fixture.TestStore.NormalizeDelimitersInRawString(sql);
 

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

@@ -752,6 +752,24 @@ SELECT 1
     WHERE [m].[CustomerID] = [o].[CustomerID])");
         }
 
+        public override async Task Multiple_occurrences_of_FromSql_with_db_parameter_adds_parameter_only_once(bool async)
+        {
+            await base.Multiple_occurrences_of_FromSql_with_db_parameter_adds_parameter_only_once(async);
+
+            AssertSql(
+                @"city='Seattle' (Nullable = false) (Size = 7)
+
+SELECT [m].[CustomerID], [m].[Address], [m].[City], [m].[CompanyName], [m].[ContactName], [m].[ContactTitle], [m].[Country], [m].[Fax], [m].[Phone], [m].[PostalCode], [m].[Region]
+FROM (
+    SELECT * FROM ""Customers"" WHERE ""City"" = @city
+) AS [m]
+INTERSECT
+SELECT [m0].[CustomerID], [m0].[Address], [m0].[City], [m0].[CompanyName], [m0].[ContactName], [m0].[ContactTitle], [m0].[Country], [m0].[Fax], [m0].[Phone], [m0].[PostalCode], [m0].[Region]
+FROM (
+    SELECT * FROM ""Customers"" WHERE ""City"" = @city
+) AS [m0]");
+        }
+
         protected override DbParameter CreateDbParameter(string name, object value)
             => new SqlParameter { ParameterName = name, Value = value };
 

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

@@ -1,8 +1,11 @@
 // Licensed to the .NET Foundation under one or more agreements.
 // The .NET Foundation licenses this file to you under the MIT license.
 
+using System.Linq;
 using System.Threading.Tasks;
+using Microsoft.Data.SqlClient;
 using Microsoft.EntityFrameworkCore.TestUtilities;
+using Xunit;
 
 // ReSharper disable InconsistentNaming
 namespace Microsoft.EntityFrameworkCore.Query
@@ -317,5 +320,66 @@ HAVING COUNT(*) = 1
 WHERE [t].[TableId] = 123
 ORDER BY [t].[ParcelNumber]");
         }
+
+        [ConditionalTheory]
+        [MemberData(nameof(IsAsyncData))]
+        public virtual async Task Muliple_occurrences_of_FromSql_in_group_by_aggregate(bool async)
+        {
+            var contextFactory = await InitializeAsync<Context27427>();
+            using var context = contextFactory.CreateContext();
+            var query = context.DemoEntities
+                     .FromSqlRaw("SELECT * FROM DemoEntities WHERE Id = {0}", new SqlParameter { Value = 1 })
+                     .Select(e => e.Id);
+
+            var query2 = context.DemoEntities
+                     .Where(e => query.Contains(e.Id))
+                     .GroupBy(e => e.Id)
+                     .Select(g => new { g.Key, Aggregate = g.Count() });
+
+            if (async)
+            {
+                await query2.ToListAsync();
+            }
+            else
+            {
+                query2.ToList();
+            }
+
+            AssertSql(
+                @"p0='1'
+
+SELECT [d].[Id] AS [Key], (
+    SELECT COUNT(*)
+    FROM [DemoEntities] AS [d0]
+    WHERE EXISTS (
+        SELECT 1
+        FROM (
+            SELECT * FROM DemoEntities WHERE Id = @p0
+        ) AS [m0]
+        WHERE [m0].[Id] = [d0].[Id]) AND ([d].[Id] = [d0].[Id])) AS [Aggregate]
+FROM [DemoEntities] AS [d]
+WHERE EXISTS (
+    SELECT 1
+    FROM (
+        SELECT * FROM DemoEntities WHERE Id = @p0
+    ) AS [m]
+    WHERE [m].[Id] = [d].[Id])
+GROUP BY [d].[Id]");
+        }
+
+        protected class Context27427 : DbContext
+        {
+            public Context27427(DbContextOptions options)
+                   : base(options)
+            {
+            }
+
+            public DbSet<DemoEntity> DemoEntities { get; set; }
+        }
+
+        protected class DemoEntity
+        {
+            public int Id { get; set; }
+        }
     }
 }