CSHARP-4622: Process constant expression to a filter query (#1074)

Author: sanych-sun

src/MongoDB.Driver/Linq/Linq3Implementation/Ast/Optimizers/AstSimplifier.cs

@@ -307,21 +307,6 @@ static AstExpression UltimateGetFieldInput(AstGetFieldExpression getField)
             }
         }
 
-        public override AstNode VisitMatchStage(AstMatchStage node)
-        {
-            node = (AstMatchStage)base.VisitMatchStage(node);
-
-            if (node.Filter is AstExprFilter exprFilter &&
-                exprFilter.Expression is AstConstantExpression constantExpression &&
-                constantExpression.Value is BsonBoolean booleanValue)
-            {
-                var simpleFilter = booleanValue.Value ? AstFilter.MatchesEverything() : AstFilter.MatchesNothing();
-                return AstStage.Match(simpleFilter);
-            }
-
-            return node;
-        }
-
         public override AstNode VisitProjectStageSetFieldSpecification(AstProjectStageSetFieldSpecification node)
         {
             node = (AstProjectStageSetFieldSpecification)base.VisitProjectStageSetFieldSpecification(node);

src/MongoDB.Driver/Linq/Linq3Implementation/Translators/ExpressionToFilterTranslators/ExpressionToFilterTranslator.cs

@@ -110,6 +110,9 @@ private static AstFilter TranslateUsingQueryOperators(TranslationContext context
 
                 case ExpressionType.TypeIs:
                     return TypeIsExpressionToFilterTranslator.Translate(context, (TypeBinaryExpression)expression);
+
+                case ExpressionType.Constant:
+                    return ConstantExpressionToFilterTranslator.Translate(context, (ConstantExpression)expression);
             }
 
             if (expression.Type == typeof(bool))

src/MongoDB.Driver/Linq/Linq3Implementation/Translators/ExpressionToFilterTranslators/ExpressionTranslators/ConstantExpressionToFilterTranslator.cs

@@ -0,0 +1,33 @@
+/* Copyright 2010-present MongoDB Inc.
+*
+* Licensed under the Apache License, Version 2.0 (the "License");
+* you may not use this file except in compliance with the License.
+* You may obtain a copy of the License at
+*
+* http://www.apache.org/licenses/LICENSE-2.0
+*
+* Unless required by applicable law or agreed to in writing, software
+* distributed under the License is distributed on an "AS IS" BASIS,
+* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+* See the License for the specific language governing permissions and
+* limitations under the License.
+*/
+
+using System.Linq.Expressions;
+using MongoDB.Driver.Linq.Linq3Implementation.Ast.Filters;
+
+namespace MongoDB.Driver.Linq.Linq3Implementation.Translators.ExpressionToFilterTranslators.ExpressionTranslators
+{
+    internal static class ConstantExpressionToFilterTranslator
+    {
+        public static AstFilter Translate(TranslationContext context, ConstantExpression expression)
+        {
+            if (expression.Type == typeof(bool))
+            {
+                return ((bool)expression.Value) ? AstFilter.MatchesEverything() : AstFilter.MatchesNothing();
+            }
+
+            throw new ExpressionNotSupportedException(expression);
+        }
+    }
+}

tests/MongoDB.Driver.Tests/Linq/Linq3ImplementationTests/Jira/CSharp4622Tests.cs

@@ -0,0 +1,52 @@
+/* Copyright 2010-present MongoDB Inc.
+*
+* Licensed under the Apache License, Version 2.0 (the "License");
+* you may not use this file except in compliance with the License.
+* You may obtain a copy of the License at
+*
+* http://www.apache.org/licenses/LICENSE-2.0
+*
+* Unless required by applicable law or agreed to in writing, software
+* distributed under the License is distributed on an "AS IS" BASIS,
+* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+* See the License for the specific language governing permissions and
+* limitations under the License.
+*/
+
+using FluentAssertions;
+using MongoDB.Driver.Linq;
+using MongoDB.TestHelpers.XunitExtensions;
+using Xunit;
+
+namespace MongoDB.Driver.Tests.Linq.Linq3ImplementationTests.Jira
+{
+    public class CSharp4622Tests : Linq3IntegrationTest
+    {
+        [Theory]
+        [ParameterAttributeData]
+        public void ReplaceOne(
+            [Values(LinqProvider.V2, LinqProvider.V3)] LinqProvider linqProvider)
+        {
+            var collection = GetCollection(linqProvider);
+            var options = new ReplaceOptions { IsUpsert = true };
+            var data = new Data { Id = 8, Text = "updated" };
+
+            var result = collection.ReplaceOne(d => true, data, options);
+
+            result.UpsertedId.Should().Be(8);
+        }
+
+        private IMongoCollection<Data> GetCollection(LinqProvider linqProvider)
+        {
+            var collection = GetCollection<Data>("test", linqProvider);
+            CreateCollection(collection);
+            return collection;
+        }
+
+        private class Data
+        {
+            public int Id { get; set; }
+            public string Text { get; set; }
+        }
+    }
+}

tests/MongoDB.Driver.Tests/Linq/Linq3ImplementationTests/Translators/ExpressionToFilterTranslators/ExpressionTranslators/ConstantExpressionToFilterTranslatorTests.cs

@@ -0,0 +1,63 @@
+/* Copyright 2010-present MongoDB Inc.
+*
+* Licensed under the Apache License, Version 2.0 (the "License");
+* you may not use this file except in compliance with the License.
+* You may obtain a copy of the License at
+*
+* http://www.apache.org/licenses/LICENSE-2.0
+*
+* Unless required by applicable law or agreed to in writing, software
+* distributed under the License is distributed on an "AS IS" BASIS,
+* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+* See the License for the specific language governing permissions and
+* limitations under the License.
+*/
+
+using System;
+using System.Collections.Generic;
+using System.Linq.Expressions;
+using FluentAssertions;
+using MongoDB.Bson;
+using MongoDB.Driver.Linq;
+using MongoDB.Driver.Linq.Linq3Implementation.Ast.Filters;
+using MongoDB.Driver.Linq.Linq3Implementation.Translators.ExpressionToFilterTranslators.ExpressionTranslators;
+using Xunit;
+
+namespace MongoDB.Driver.Tests.Linq.Linq3ImplementationTests.Translators.ExpressionToFilterTranslators.ExpressionTranslators
+{
+    public class ConstantExpressionToFilterTranslatorTests
+    {
+        [Theory]
+        [MemberData(nameof(SupportedConstantExpressions))]
+        public void Translate_should_process_supported_constants(ConstantExpression expression, BsonValue expectedFilter)
+        {
+            var result = ConstantExpressionToFilterTranslator.Translate(null, expression);
+
+            result.Render().Should().Be(expectedFilter);
+        }
+
+        [Theory]
+        [MemberData(nameof(NotSupportedConstantExpressions))]
+        public void Translate_throws_on_not_supported_constants(ConstantExpression expression)
+        {
+            var ex = Record.Exception(() => ConstantExpressionToFilterTranslator.Translate(null, expression));
+
+            ex.Should().BeOfType<ExpressionNotSupportedException>();
+        }
+
+        public static IEnumerable<object[]> SupportedConstantExpressions()
+        {
+            yield return new object[] { Expression.Constant(true), AstFilter.MatchesEverything().Render() };
+            yield return new object[] { Expression.Constant(false), AstFilter.MatchesNothing().Render() };
+        }
+
+        public static IEnumerable<object[]> NotSupportedConstantExpressions()
+        {
+            yield return new object[] { Expression.Constant(null) };
+            yield return new object[] { Expression.Constant(1) };
+            yield return new object[] { Expression.Constant(0) };
+            yield return new object[] { Expression.Constant(string.Empty) };
+            yield return new object[] { Expression.Constant("ignore") };
+        }
+    }
+}