CSHARP-5448: Refactor AstFilterField and AstPipeline to remove reference to serializers.

Author: rstam

src/MongoDB.Driver/FilterDefinitionBuilder.cs

@@ -2165,7 +2165,7 @@ public override BsonDocument Render(RenderArgs<TDocument> args)
                     throw new NotSupportedException($"OfType requires that documents of type {BsonUtils.GetFriendlyTypeName(typeof(TDerived))} have a discriminator value.");
                 }
 
-                var discriminatorField = new AstFilterField(discriminatorConvention.ElementName, BsonValueSerializer.Instance);
+                var discriminatorField = new AstFilterField(discriminatorConvention.ElementName);
                 ofTypeFilter= discriminatorConvention switch
                 {
                     IHierarchicalDiscriminatorConvention hierarchicalDiscriminatorConvention => DiscriminatorAstFilter.TypeIs(discriminatorField, hierarchicalDiscriminatorConvention, nominalType, actualType),
@@ -2223,7 +2223,7 @@ public override BsonDocument Render(RenderArgs<TDocument> args)
                 }
 
                 var discriminatorElementName = renderedField.FieldName + "." + discriminatorConvention.ElementName;
-                var discriminatorField = new AstFilterField(discriminatorElementName, BsonValueSerializer.Instance);
+                var discriminatorField = new AstFilterField(discriminatorElementName);
 
                 ofTypeFilter = discriminatorConvention switch
                 {

src/MongoDB.Driver/Linq/Linq3Implementation/Ast/AstPipeline.cs

@@ -14,7 +14,6 @@
 */
 
 using MongoDB.Bson;
-using MongoDB.Bson.Serialization;
 using MongoDB.Driver.Core.Misc;
 using MongoDB.Driver.Linq.Linq3Implementation.Ast.Stages;
 using MongoDB.Driver.Linq.Linq3Implementation.Ast.Visitors;
@@ -27,68 +26,39 @@ namespace MongoDB.Driver.Linq.Linq3Implementation.Ast
     internal sealed class AstPipeline : AstNode
     {
         #region static
-        public static AstPipeline Empty(IBsonSerializer outputSerializer)
-        {
-            return new AstPipeline(Enumerable.Empty<AstStage>(), outputSerializer);
-        }
+        private static readonly AstPipeline __empty = new AstPipeline([]);
+
+        public static AstPipeline Empty => __empty;
         #endregion
 
-        private IBsonSerializer _outputSerializer;
         private readonly IReadOnlyList<AstStage> _stages;
 
-        public AstPipeline(IEnumerable<AstStage> stages, IBsonSerializer outputSerializer)
+        public AstPipeline(IEnumerable<AstStage> stages)
         {
             _stages = Ensure.IsNotNull(stages, nameof(stages)).AsReadOnlyList();
-            _outputSerializer = Ensure.IsNotNull(outputSerializer, nameof(outputSerializer));
         }
 
         public override AstNodeType NodeType => AstNodeType.Pipeline;
-        public IBsonSerializer OutputSerializer => _outputSerializer;
         public IReadOnlyList<AstStage> Stages => _stages;
 
         public override AstNode Accept(AstNodeVisitor visitor)
         {
             return visitor.VisitPipeline(this);
         }
 
-        public AstPipeline AddStages(
-            IBsonSerializer newOutputSerializer,
-            params AstStage[] newStages)
-        {
-            var stages = _stages.Concat(newStages);
-            return new AstPipeline(stages, newOutputSerializer);
-        }
-
-        public override BsonValue Render()
+       public override BsonValue Render()
         {
             return new BsonArray(_stages.Select(s => s.Render()));
         }
 
-        public AstPipeline ReplaceLastStage(
-            IBsonSerializer newOutputSerializer,
-            AstStage newLastStage)
-        {
-            var stages = _stages.Take(_stages.Count - 1).Concat(new[] { newLastStage });
-            return new AstPipeline(stages, newOutputSerializer);
-        }
-
-        public AstPipeline ReplaceStagesAtEnd(
-            IBsonSerializer newOutputSerializer,
-            int numberOfStagesToReplace,
-            params AstStage[] newStages)
-        {
-            var stages = _stages.Take(_stages.Count - numberOfStagesToReplace).Concat(newStages);
-            return new AstPipeline(stages, newOutputSerializer);
-        }
-
         public AstPipeline Update(IEnumerable<AstStage> stages)
         {
             if (stages == _stages)
             {
                 return this;
             }
 
-            return new AstPipeline(stages, _outputSerializer);
+            return new AstPipeline(stages);
         }
     }
 }

src/MongoDB.Driver/Linq/Linq3Implementation/Ast/Filters/AstFieldOperationFilter.cs

@@ -31,14 +31,6 @@ public AstFieldOperationFilter(AstFilterField field, AstFilterOperation operatio
             _field = Ensure.IsNotNull(field, nameof(field));
             _operation = Ensure.IsNotNull(operation, nameof(operation));
 
-            if (operation.NodeType == AstNodeType.RegexFilterOperation &&
-                field.Serializer is IRepresentationConfigurable representationConfigurable &&
-                representationConfigurable.Representation != BsonType.String)
-            {
-                // normally an ExpressionNotSupported should have been thrown before reaching here
-                throw new ArgumentException($"Field must be represented as a string for regex filter operations: {field.Path}", nameof(field));
-            }
-
             if (_field.Path == "@<current>")
             {
                 throw new ExpressionNotSupportedException("Field path cannot be \"@<current>\" in AstFieldOperationFilter.");

src/MongoDB.Driver/Linq/Linq3Implementation/Ast/Filters/AstFilter.cs

@@ -134,9 +134,9 @@ public static AstFilter Expr(AstExpression expression)
             return new AstExprFilter(expression);
         }
 
-        public static AstFilterField Field(string path, IBsonSerializer serializer)
+        public static AstFilterField Field(string path)
         {
-            return new AstFilterField(path, serializer);
+            return new AstFilterField(path);
         }
 
         public static AstFieldOperationFilter In(AstFilterField field, IEnumerable<BsonValue> values)

src/MongoDB.Driver/Linq/Linq3Implementation/Ast/Filters/AstFilterField.cs

@@ -14,7 +14,6 @@
 */
 
 using MongoDB.Bson;
-using MongoDB.Bson.Serialization;
 using MongoDB.Driver.Core.Misc;
 using MongoDB.Driver.Linq.Linq3Implementation.Ast.Visitors;
 
@@ -23,34 +22,31 @@ namespace MongoDB.Driver.Linq.Linq3Implementation.Ast.Filters
     internal sealed class AstFilterField : AstNode
     {
         private string _path;
-        private IBsonSerializer _serializer;
 
-        public AstFilterField(string path, IBsonSerializer serializer)
+        public AstFilterField(string path)
         {
             _path = Ensure.IsNotNull(path, nameof(path));
-            _serializer = Ensure.IsNotNull(serializer, nameof(serializer));
         }
 
         public string Path => _path;
         public override AstNodeType NodeType => AstNodeType.FilterField;
-        public IBsonSerializer Serializer => _serializer;
 
         public override AstNode Accept(AstNodeVisitor visitor)
         {
             return visitor.VisitFilterField(this);
         }
 
-        public AstFilterField SubField(string subFieldName, IBsonSerializer subFieldSerializer)
+        public AstFilterField SubField(string subFieldName)
         {
             Ensure.IsNotNull(subFieldName, nameof(subFieldName));
 
             if (_path == "@<current>")
             {
-                return new AstFilterField(subFieldName, subFieldSerializer);
+                return new AstFilterField(subFieldName);
             }
             else
             {
-                return new AstFilterField(_path + "." + subFieldName, subFieldSerializer);
+                return new AstFilterField(_path + "." + subFieldName);
             }
         }
 

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

@@ -340,7 +340,7 @@ public override AstNode VisitFilterField(AstFilterField node)
                     var accumulatorFieldName = _accumulators.AddAccumulatorExpression(accumulatorExpression);
                     var restOfPath = node.Path.Substring("_elements.0.".Length);
                     var rewrittenPath = $"{accumulatorFieldName}.{restOfPath}";
-                    return AstFilter.Field(rewrittenPath, node.Serializer);
+                    return AstFilter.Field(rewrittenPath);
                 }
 
                 if (node.Path == "_elements" || node.Path.StartsWith("_elements."))

src/MongoDB.Driver/Linq/Linq3Implementation/GroupingWithOutputExpressionStageDefinitions.cs

@@ -73,7 +73,7 @@ private AstStage RenderProjectStage(
 
         private IReadOnlyList<AstStage> OptimizeGroupingStages(AstStage groupingStage, AstStage projectStage, IBsonSerializer inputSerializer, IBsonSerializer outputSerializer)
         {
-            var pipeline = AstPipeline.Empty(inputSerializer).AddStages(outputSerializer, groupingStage, projectStage);
+            var pipeline = new AstPipeline([groupingStage, projectStage]);
             var optimizedPipeline = AstPipelineOptimizer.Optimize(pipeline);
             return optimizedPipeline.Stages;
         }

src/MongoDB.Driver/Linq/Linq3Implementation/Misc/ClientSideProjectionHelper.cs

@@ -26,7 +26,7 @@ internal static class ClientSideProjectionHelper
         // public static methods
         public static void ThrowIfClientSideProjection(
             Expression expression,
-            AstPipeline pipeline,
+            TranslatedPipeline pipeline,
             MethodInfo method)
         {
             if (pipeline.OutputSerializer is IClientSideProjectionDeserializer)
@@ -37,7 +37,7 @@ public static void ThrowIfClientSideProjection(
 
         public static void ThrowIfClientSideProjection(
             Expression expression,
-            AstPipeline pipeline,
+            TranslatedPipeline pipeline,
             MethodInfo method,
             string methodOverload)
         {

src/MongoDB.Driver/Linq/Linq3Implementation/Translators/DiscriminatorAstFilter.cs

@@ -37,7 +37,7 @@ public static AstFilter TypeEquals(AstFilterField discriminatorField, IHierarchi
         }
         else
         {
-            var discriminatorFieldItemZero = discriminatorField.SubField("0", BsonValueSerializer.Instance);
+            var discriminatorFieldItemZero = discriminatorField.SubField("0");
             return AstFilter.And(
                 AstFilter.NotExists(discriminatorFieldItemZero), // required to avoid false matches on subclasses
                 AstFilter.Eq(discriminatorField, discriminator));

src/MongoDB.Driver/Linq/Linq3Implementation/Translators/ExpressionToExecutableQueryTranslators/ContainsMethodToExecutableQueryTranslator.cs

@@ -70,7 +70,7 @@ public static ExecutableQuery<TDocument, bool> Translate<TDocument>(MongoQueryPr
                 var itemValue = itemExpression.GetConstantValue<object>(containingExpression: expression);
                 var serializedValue = SerializationHelper.SerializeValue(pipeline.OutputSerializer, itemValue);
 
-                AstFilter filter = AstFilter.Eq(AstFilter.Field("_v", valueSerializer), serializedValue);
+                AstFilter filter = AstFilter.Eq(AstFilter.Field("_v"), serializedValue);
                 pipeline = pipeline.AddStages(
                     __outputSerializer,
                     AstStage.Match(filter),