Query: Fix double negation in SQL generation

Resolves #26309
dotnet · Nov 17, 2021 · 9e4eb9a · 9e4eb9a
1 parent 02f2450
commit 9e4eb9a
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diff --git a/src/EFCore.Relational/Query/QuerySqlGenerator.cs b/src/EFCore.Relational/Query/QuerySqlGenerator.cs
@@ -676,20 +676,56 @@ protected override Expression VisitSqlUnary(SqlUnaryExpression sqlUnaryExpressio
                 case ExpressionType.Not:
                 {
                     _relationalCommandBuilder.Append("~");
+
+                    var requiresBrackets = RequiresParentheses(sqlUnaryExpression, sqlUnaryExpression.Operand);
+                    if (requiresBrackets)
+                    {
+                        _relationalCommandBuilder.Append("(");
+                    }
+
                     Visit(sqlUnaryExpression.Operand);
+                    if (requiresBrackets)
+                    {
+                        _relationalCommandBuilder.Append(")");
+                    }
+
                     break;
                 }
 
                 case ExpressionType.Equal:
                 {
+
+                    var requiresBrackets = RequiresParentheses(sqlUnaryExpression, sqlUnaryExpression.Operand);
+                    if (requiresBrackets)
+                    {
+                        _relationalCommandBuilder.Append("(");
+                    }
+
                     Visit(sqlUnaryExpression.Operand);
+                    if (requiresBrackets)
+                    {
+                        _relationalCommandBuilder.Append(")");
+                    }
+
                     _relationalCommandBuilder.Append(" IS NULL");
                     break;
                 }
 
                 case ExpressionType.NotEqual:
                 {
+
+                    var requiresBrackets = RequiresParentheses(sqlUnaryExpression, sqlUnaryExpression.Operand);
+                    if (requiresBrackets)
+                    {
+                        _relationalCommandBuilder.Append("(");
+                    }
+
                     Visit(sqlUnaryExpression.Operand);
+                    if (requiresBrackets)
+                    {
+                        _relationalCommandBuilder.Append(")");
+                    }
+
                     _relationalCommandBuilder.Append(" IS NOT NULL");
                     break;
                 }
@@ -799,6 +835,13 @@ protected virtual bool RequiresParentheses(SqlExpression outerExpression, SqlExp
                         return true;
                     }
 
+                    if (sqlUnaryExpression.OperatorType == ExpressionType.Negate
+                        && outerExpression is SqlUnaryExpression { OperatorType: ExpressionType.Negate })
+                    {
+                        // double negative sign has different meaning so we need to enclose it in brackets
+                        return true;
+                    }
+
                     return false;
                 }
 

diff --git a/test/EFCore.Specification.Tests/Query/GearsOfWarQueryTestBase.cs b/test/EFCore.Specification.Tests/Query/GearsOfWarQueryTestBase.cs
@@ -60,6 +60,15 @@ public virtual Task Negate_on_column(bool async)
                 ss => ss.Set<Squad>().Where(s => s.Id == -s.Id));
         }
 
+        [ConditionalTheory]
+        [MemberData(nameof(IsAsyncData))]
+        public virtual Task Double_negate_on_column(bool async)
+        {
+            return AssertQuery(
+                async,
+                ss => ss.Set<Squad>().Where(s => -(-s.Id) == s.Id));
+        }
+
         [ConditionalTheory]
         [MemberData(nameof(IsAsyncData))]
         public virtual Task Negate_on_like_expression(bool async)

diff --git a/test/EFCore.SqlServer.FunctionalTests/Query/GearsOfWarQuerySqlServerTest.cs b/test/EFCore.SqlServer.FunctionalTests/Query/GearsOfWarQuerySqlServerTest.cs
@@ -44,6 +44,16 @@ FROM [Squads] AS [s]
 WHERE [s].[Id] = -[s].[Id]");
         }
 
+        public override async Task Double_negate_on_column(bool async)
+        {
+            await base.Double_negate_on_column(async);
+
+            AssertSql(
+                @"SELECT [s].[Id], [s].[Banner], [s].[Banner5], [s].[InternalNumber], [s].[Name]
+FROM [Squads] AS [s]
+WHERE -(-[s].[Id]) = [s].[Id]");
+        }
+
         public override async Task Negate_on_like_expression(bool async)
         {
             await base.Negate_on_like_expression(async);

diff --git a/test/EFCore.SqlServer.FunctionalTests/Query/TPTGearsOfWarQuerySqlServerTest.cs b/test/EFCore.SqlServer.FunctionalTests/Query/TPTGearsOfWarQuerySqlServerTest.cs
@@ -43,6 +43,16 @@ FROM [Squads] AS [s]
 WHERE [s].[Id] = -[s].[Id]");
         }
 
+        public override async Task Double_negate_on_column(bool async)
+        {
+            await base.Double_negate_on_column(async);
+
+            AssertSql(
+                @"SELECT [s].[Id], [s].[Banner], [s].[Banner5], [s].[InternalNumber], [s].[Name]
+FROM [Squads] AS [s]
+WHERE -(-[s].[Id]) = [s].[Id]");
+        }
+
         public override async Task Negate_on_like_expression(bool async)
         {
             await base.Negate_on_like_expression(async);