Improvement

Author: papafe

src/MongoDB.Driver/Search/SearchDefinition.cs

@@ -157,17 +157,15 @@ public override BsonDocument Render(RenderArgs<TDocument> args)
         {
             BsonDocument renderedArgs;
 
-            if (_path is SingleSearchPathDefinition<TDocument> singleSearchPathDefinition)
+            if (_path is null)
             {
-                // Special case for SingleSearchPathDefinition in order to avoid rendering the path twice
-                var (renderedPath, renderedField) = _path.GetRenderedFieldAndStringPath(singleSearchPathDefinition.Field, args);
-                renderedArgs = RenderArguments(args, renderedField.FieldSerializer);
-                renderedArgs.Add("path", renderedPath);
+                renderedArgs = RenderArguments(args);
             }
             else
             {
-                renderedArgs = RenderArguments(args);
-                renderedArgs.Add("path", () => _path.Render(args), _path != null);
+                var (renderedPath, fieldSerializer) = _path.RenderAndGetFieldSerializer(args);
+                renderedArgs = RenderArguments(args, fieldSerializer);
+                renderedArgs.Add("path", renderedPath);
             }
 
             renderedArgs.Add("score", () => _score.Render(args), _score != null);

src/MongoDB.Driver/Search/SearchPathDefinition.cs

@@ -16,6 +16,7 @@
 using System.Collections.Generic;
 using System.Linq;
 using MongoDB.Bson;
+using MongoDB.Bson.Serialization;
 
 namespace MongoDB.Driver.Search
 {
@@ -104,15 +105,17 @@ public static implicit operator SearchPathDefinition<TDocument>(List<string> fie
         /// <param name="args">The render arguments.</param>
         /// <returns>The rendered field.</returns>
         protected string RenderField(FieldDefinition<TDocument> fieldDefinition, RenderArgs<TDocument> args)
-            => GetRenderedFieldAndStringPath(fieldDefinition, args).renderedPath;
+            => RenderFieldWithSerializer(fieldDefinition, args).renderedPath;
 
-        internal (string renderedPath, RenderedFieldDefinition renderedFieldDefinition) GetRenderedFieldAndStringPath(FieldDefinition<TDocument> fieldDefinition, RenderArgs<TDocument> args)
+        internal virtual (BsonValue, IBsonSerializer) RenderAndGetFieldSerializer(RenderArgs<TDocument> args) => (Render(args), null);
+
+        internal (string renderedPath, IBsonSerializer fieldSerializer) RenderFieldWithSerializer(FieldDefinition<TDocument> fieldDefinition, RenderArgs<TDocument> args)
         {
             var renderedField = fieldDefinition.Render(args);
             var prefix = args.PathRenderArgs.PathPrefix;
             var renderedString = prefix == null ? renderedField.FieldName : $"{prefix}.{renderedField.FieldName}";
 
-            return (renderedString, renderedField);
+            return (renderedString, renderedField.FieldSerializer);
         }
     }
 }

src/MongoDB.Driver/Search/SearchPathDefinitionBuilder.cs

@@ -18,6 +18,7 @@
 using System.Linq;
 using System.Linq.Expressions;
 using MongoDB.Bson;
+using MongoDB.Bson.Serialization;
 using MongoDB.Driver.Core.Misc;
 
 namespace MongoDB.Driver.Search
@@ -137,15 +138,16 @@ internal sealed class SingleSearchPathDefinition<TDocument> : SearchPathDefiniti
     {
         private readonly FieldDefinition<TDocument> _field;
 
-        public FieldDefinition<TDocument> Field => _field;
-
         public SingleSearchPathDefinition(FieldDefinition<TDocument> field)
         {
             _field = Ensure.IsNotNull(field, nameof(field));
         }
 
         public override BsonValue Render(RenderArgs<TDocument> args) =>
             RenderField(_field, args);
+
+        internal override (BsonValue, IBsonSerializer) RenderAndGetFieldSerializer(RenderArgs<TDocument> args)
+            => RenderFieldWithSerializer(_field, args);
     }
 
     internal sealed class WildcardSearchPathDefinition<TDocument> : SearchPathDefinition<TDocument>