CSHARP-5672: Support sorting by value in updateDefinition builders

Author: adelinowona

src/MongoDB.Driver/SortDefinitionBuilder.cs

@@ -130,6 +130,15 @@ public static SortDefinition<TDocument> MetaTextScore<TDocument>(this SortDefini
     /// <typeparam name="TDocument">The type of the document.</typeparam>
     public sealed class SortDefinitionBuilder<TDocument>
     {
+        /// <summary>
+        /// Creates a value ascending sort.
+        /// </summary>
+        /// <returns>An ascending sort.</returns>
+        public SortDefinition<TDocument> Ascending()
+        {
+            return new NoFieldDirectionalSortDefinition<TDocument>(SortDirection.Ascending);
+        }
+
         /// <summary>
         /// Creates an ascending sort.
         /// </summary>
@@ -170,6 +179,15 @@ public SortDefinition<TDocument> Combine(IEnumerable<SortDefinition<TDocument>>
             return new CombinedSortDefinition<TDocument>(sorts);
         }
 
+        /// <summary>
+        /// Creates a value descending sort.
+        /// </summary>
+        /// <returns>A descending sort.</returns>
+        public SortDefinition<TDocument> Descending()
+        {
+            return new NoFieldDirectionalSortDefinition<TDocument>(SortDirection.Descending);
+        }
+
         /// <summary>
         /// Creates a descending sort.
         /// </summary>
@@ -288,4 +306,26 @@ public override BsonDocument Render(RenderArgs<TDocument> args)
             return new BsonDocument(renderedField.FieldName, value);
         }
     }
+
+    internal sealed class NoFieldDirectionalSortDefinition<TDocument> : SortDefinition<TDocument>
+    {
+        private readonly SortDirection _direction;
+
+        public NoFieldDirectionalSortDefinition(SortDirection direction)
+        {
+            _direction = direction;
+        }
+
+        public override BsonDocument Render(RenderArgs<TDocument> args)
+        {
+            BsonValue value = _direction switch
+            {
+                SortDirection.Ascending => 1,
+                SortDirection.Descending => -1,
+                _ => throw new InvalidOperationException("Unknown value for " + typeof(SortDirection) + ".")
+            };
+
+            return new BsonDocument("direction",  value);
+        }
+    }
 }

src/MongoDB.Driver/UpdateDefinitionBuilder.cs

@@ -1685,7 +1685,13 @@ public override BsonValue Render(RenderArgs<TDocument> args)
 
             if (_sort != null)
             {
-                document["$push"][renderedField.FieldName]["$sort"] = _sort.Render(args.WithNewDocumentType((IBsonSerializer<TItem>)itemSerializer));
+                var newArgs = args.WithNewDocumentType((IBsonSerializer<TItem>)itemSerializer);
+
+                var renderedSort = _sort is NoFieldDirectionalSortDefinition<TItem>
+                    ? _sort.Render(newArgs)["direction"]
+                    : _sort.Render(newArgs);
+
+                document["$push"][renderedField.FieldName]["$sort"] = renderedSort;
             }
 
             return document;