CSHARP-3399: Mitigate pain of using field names with dots and dollars.

src/MongoDB.Bson/IO/NoOpElementNameValidator.cs

@@ -14,6 +14,8 @@
 */
 
 
+using System;
+
 namespace MongoDB.Bson.IO
 {
     /// <summary>
@@ -54,6 +56,10 @@ public IElementNameValidator GetValidatorForChildContent(string elementName)
         /// <returns>True if the element name is valid.</returns>
         public bool IsValidElementName(string elementName)
         {
+            if (elementName == null)
+            {
+                throw new ArgumentNullException(nameof(elementName), "Value cannot be null.");
+            }
             return true;
         }
     }

src/MongoDB.Driver.Core/Core/Operations/ElementNameValidators/ElementNameValidatorFactory.cs

@@ -32,7 +32,7 @@ public static IElementNameValidator ForUpdateType(UpdateType updateType)
             switch (updateType)
             {
                 case UpdateType.Replacement:
-                    return CollectionElementNameValidator.Instance;
+                    return ReplacementElementNameValidator.Instance;
                 case UpdateType.Update:
                     return UpdateElementNameValidator.Instance;
                 default:

src/MongoDB.Driver.Core/Core/Operations/ElementNameValidators/CollectionElementNameValidator.cs → src/MongoDB.Driver.Core/Core/Operations/ElementNameValidators/ReplacementElementNameValidator.cs

@@ -1,4 +1,4 @@
-/* Copyright 2013-present MongoDB Inc.
+/* Copyright 2021-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.
@@ -13,29 +13,27 @@
 * limitations under the License.
 */
 
-using System.Collections.Generic;
 using MongoDB.Bson.IO;
 using MongoDB.Driver.Core.Misc;
 
 namespace MongoDB.Driver.Core.Operations.ElementNameValidators
 {
     /// <summary>
-    /// Represents an element name validator that checks that element names are valid for MongoDB collections.
+    /// Represents an element name validator for replace operations.
     /// </summary>
-    public class CollectionElementNameValidator : IElementNameValidator
+    public class ReplacementElementNameValidator : IElementNameValidator
     {
         // private static fields
-        private static readonly List<string> __exceptions = new List<string> { "$db", "$ref", "$id", "$code", "$scope" };
-        private static readonly CollectionElementNameValidator __instance = new CollectionElementNameValidator();
+        private static readonly ReplacementElementNameValidator __instance = new ReplacementElementNameValidator();
 
         // public static fields
         /// <summary>
-        /// Gets a pre-created instance of a CollectionElementNameValidator.
+        /// Gets a pre-created instance of an ReplacementElementNameValidator.
         /// </summary>
         /// <value>
         /// The pre-created instance.
         /// </value>
-        public static CollectionElementNameValidator Instance
+        public static ReplacementElementNameValidator Instance
         {
             get { return __instance; }
         }
@@ -44,31 +42,14 @@ public static CollectionElementNameValidator Instance
         /// <inheritdoc/>
         public IElementNameValidator GetValidatorForChildContent(string elementName)
         {
-            return this;
+            return NoOpElementNameValidator.Instance;
         }
 
         /// <inheritdoc/>
         public bool IsValidElementName(string elementName)
         {
             Ensure.IsNotNull(elementName, nameof(elementName));
-
-            if (elementName.Length == 0)
-            {
-                // the server seems to allow empty element names, but in 1.x we did not
-                return false;
-            }
-
-            if (elementName.IndexOf('.') != -1)
-            {
-                return false;
-            }
-
-            if (elementName[0] == '$' && !__exceptions.Contains(elementName))
-            {
-                return false;
-            }
-
-            return true;
+            return elementName.Length > 0 && elementName[0] != '$';
         }
     }
 }

src/MongoDB.Driver.Core/Core/Operations/ElementNameValidators/UpdateElementNameValidator.cs

@@ -14,6 +14,7 @@
 */
 
 using MongoDB.Bson.IO;
+using MongoDB.Driver.Core.Misc;
 
 namespace MongoDB.Driver.Core.Operations.ElementNameValidators
 {
@@ -47,6 +48,7 @@ public IElementNameValidator GetValidatorForChildContent(string elementName)
         /// <inheritdoc/>
         public bool IsValidElementName(string elementName)
         {
+            Ensure.IsNotNull(elementName, nameof(elementName));
             return elementName.Length > 0 && elementName[0] == '$';
         }
     }

src/MongoDB.Driver.Core/Core/Operations/ElementNameValidators/UpdateOrReplacementElementNameValidator.cs

@@ -44,16 +44,17 @@ public IElementNameValidator GetValidatorForChildContent(string elementName)
         /// <inheritdoc/>
         public bool IsValidElementName(string elementName)
         {
+            Ensure.IsNotNull(elementName, nameof(elementName));
             // the first elementName we see determines whether we are validating an update or a replacement document
             if (_chosenValidator == null)
             {
                 if (elementName.Length > 0 && elementName[0] == '$')
                 {
-                    _chosenValidator = UpdateElementNameValidator.Instance; ;
+                    _chosenValidator = UpdateElementNameValidator.Instance;
                 }
                 else
                 {
-                    _chosenValidator = CollectionElementNameValidator.Instance;
+                    _chosenValidator = ReplacementElementNameValidator.Instance;
                 }
             }
             return _chosenValidator.IsValidElementName(elementName);

src/MongoDB.Driver.Core/Core/Operations/FindOneAndReplaceOperation.cs

@@ -202,27 +202,7 @@ internal override BsonDocument CreateCommand(ICoreSessionHandle session, Connect
         /// <inheritdoc/>
         protected override IElementNameValidator GetCommandValidator()
         {
-            return Validator.Instance;
-        }
-
-        private class Validator : IElementNameValidator
-        {
-            public readonly static Validator Instance = new Validator();
-
-            public IElementNameValidator GetValidatorForChildContent(string elementName)
-            {
-                if (elementName == "update")
-                {
-                    return CollectionElementNameValidator.Instance;
-                }
-
-                return NoOpElementNameValidator.Instance;
-            }
-
-            public bool IsValidElementName(string elementName)
-            {
-                return true;
-            }
+            return NoOpElementNameValidator.Instance;
         }
     }
 }

src/MongoDB.Driver.Core/Core/Operations/FindOneAndUpdateOperation.cs

@@ -268,6 +268,7 @@ public IElementNameValidator GetValidatorForChildContent(string elementName)
 
             public bool IsValidElementName(string elementName)
             {
+                Ensure.IsNotNull(elementName, nameof(elementName));
                 return true;
             }
         }

src/MongoDB.Driver.Core/Core/Operations/RetryableInsertCommandOperation.cs

@@ -22,7 +22,6 @@
 using MongoDB.Driver.Core.Bindings;
 using MongoDB.Driver.Core.Connections;
 using MongoDB.Driver.Core.Misc;
-using MongoDB.Driver.Core.Operations.ElementNameValidators;
 using MongoDB.Driver.Core.WireProtocol.Messages;
 using MongoDB.Driver.Core.WireProtocol.Messages.Encoders;
 
@@ -133,8 +132,8 @@ protected override IEnumerable<Type1CommandMessageSection> CreateCommandPayloads
             {
                 documents = new BatchableSource<TDocument>(_documents.Items, _documents.Offset, _documents.ProcessedCount, canBeSplit: false);
             }
-            var isSystemIndexesCollection = _collectionNamespace.Equals(CollectionNamespace.DatabaseNamespace.SystemIndexesCollection);
-            var elementNameValidator = isSystemIndexesCollection ? (IElementNameValidator)NoOpElementNameValidator.Instance : CollectionElementNameValidator.Instance;
+
+            var elementNameValidator = NoOpElementNameValidator.Instance;
             var maxBatchCount = Math.Min(MaxBatchCount ?? int.MaxValue, channel.ConnectionDescription.MaxBatchCount);
             var maxDocumentSize = channel.ConnectionDescription.MaxDocumentSize;
             var payload = new Type1CommandMessageSection<TDocument>("documents", documents, _documentSerializer, elementNameValidator, maxBatchCount, maxDocumentSize);

src/MongoDB.Driver.Core/Core/WireProtocol/Messages/Encoders/BinaryEncoders/InsertMessageBinaryEncoder.cs

@@ -142,49 +142,37 @@ private void WriteDocuments(BsonBinaryWriter writer, long messageStartPosition,
             var stream = writer.BsonStream;
             var context = BsonSerializationContext.CreateRoot(writer);
 
-            var collectionNamespace = message.CollectionNamespace;
-            var isSystemIndexesCollection = collectionNamespace.Equals(collectionNamespace.DatabaseNamespace.SystemIndexesCollection);
-            var elementNameValidator = isSystemIndexesCollection ? (IElementNameValidator)NoOpElementNameValidator.Instance : CollectionElementNameValidator.Instance;
-
-            writer.PushElementNameValidator(elementNameValidator);
-            try
+            var documentSource = message.DocumentSource;
+            var batchCount = Math.Min(documentSource.Count, message.MaxBatchCount);
+            if (batchCount < documentSource.Count && !documentSource.CanBeSplit)
             {
-                var documentSource = message.DocumentSource;
-                var batchCount = Math.Min(documentSource.Count, message.MaxBatchCount);
-                if (batchCount < documentSource.Count && !documentSource.CanBeSplit)
-                {
-                    throw new BsonSerializationException("Batch is too large.");
-                }
+                throw new BsonSerializationException("Batch is too large.");
+            }
 
-                for (var i = 0; i < batchCount; i++)
-                {
-                    var document = documentSource.Items[documentSource.Offset + i];
-                    var documentStartPosition = stream.Position;
+            for (var i = 0; i < batchCount; i++)
+            {
+                var document = documentSource.Items[documentSource.Offset + i];
+                var documentStartPosition = stream.Position;
 
-                    _serializer.Serialize(context, document);
+                _serializer.Serialize(context, document);
 
-                    var messageSize = stream.Position - messageStartPosition;
-                    if (messageSize > message.MaxMessageSize)
+                var messageSize = stream.Position - messageStartPosition;
+                if (messageSize > message.MaxMessageSize)
+                {
+                    if (i > 0 && documentSource.CanBeSplit)
+                    {
+                        stream.Position = documentStartPosition;
+                        stream.SetLength(documentStartPosition);
+                        documentSource.SetProcessedCount(i);
+                        return;
+                    }
+                    else
                     {
-                        if (i > 0 && documentSource.CanBeSplit)
-                        {
-                            stream.Position = documentStartPosition;
-                            stream.SetLength(documentStartPosition);
-                            documentSource.SetProcessedCount(i);
-                            return;
-                        }
-                        else
-                        {
-                            throw new BsonSerializationException("Batch is too large.");
-                        }
+                        throw new BsonSerializationException("Batch is too large.");
                     }
                 }
-                documentSource.SetProcessedCount(batchCount);
-            }
-            finally
-            {
-                writer.PopElementNameValidator();
             }
+            documentSource.SetProcessedCount(batchCount);
         }
 
         // explicit interface implementations

tests/MongoDB.Driver.Legacy.Tests/Jira/CSharp253Tests.cs

@@ -49,20 +49,6 @@ public void TestInsertClass()
             _collection.Insert(c);
         }
 
-        [Fact]
-        public void TestInsertDollar()
-        {
-            Assert.Throws<BsonSerializationException>(() => { _collection.Insert(new BsonDocument("$x", 1)); });
-            Assert.Throws<BsonSerializationException>(() => { _collection.Insert(new BsonDocument("x", new BsonDocument("$x", 1))); });
-        }
-
-        [Fact]
-        public void TestInsertPeriod()
-        {
-            Assert.Throws<BsonSerializationException>(() => { _collection.Insert(new BsonDocument("a.b", 1)); });
-            Assert.Throws<BsonSerializationException>(() => { _collection.Insert(new BsonDocument("a", new BsonDocument("b.c", 1))); });
-        }
-
         [Fact]
         public void TestLegacyDollar()
         {

tests/MongoDB.Driver.Legacy.Tests/Jira/CSharp265Tests.cs

@@ -121,7 +121,12 @@ public void TestGenericDictionaryDocumentRepresentationWithDollar()
             var json = d.ToJson();
             Assert.Equal(expected, json);
 
-            Assert.Throws<BsonSerializationException>(() => { __collection.Insert(d); });
+            __collection.RemoveAll();
+            __collection.Insert(d);
+            var r = __collection.FindOne(Query.EQ("_id", d.Id));
+            Assert.Equal(d.Id, r.Id);
+            Assert.Equal(1, r.Data.Count);
+            Assert.Equal(1, r.Data["$a"]);
         }
 
         [Fact]
@@ -132,7 +137,12 @@ public void TestGenericDictionaryDocumentRepresentationWithDot()
             var json = d.ToJson();
             Assert.Equal(expected, json);
 
-            Assert.Throws<BsonSerializationException>(() => { __collection.Insert(d); });
+            __collection.RemoveAll();
+            __collection.Insert(d);
+            var r = __collection.FindOne(Query.EQ("_id", d.Id));
+            Assert.Equal(d.Id, r.Id);
+            Assert.Equal(1, r.Data.Count);
+            Assert.Equal(1, r.Data["a.b"]);
         }
 
         [Fact]
@@ -160,7 +170,11 @@ public void TestGenericDictionaryDynamicRepresentationWithDollar()
             Assert.Equal(expected, json);
 
             __collection.RemoveAll();
-            Assert.Throws<BsonSerializationException>(() => __collection.Insert(d));
+            __collection.Insert(d);
+            var r = __collection.FindOne(Query.EQ("_id", d.Id));
+            Assert.Equal(d.Id, r.Id);
+            Assert.Equal(1, r.Data.Count);
+            Assert.Equal(1, r.Data["$a"]);
         }
 
         [Fact]
@@ -172,7 +186,11 @@ public void TestGenericDictionaryDynamicRepresentationWithDot()
             Assert.Equal(expected, json);
 
             __collection.RemoveAll();
-            Assert.Throws<BsonSerializationException>(() => __collection.Insert(d));
+            __collection.Insert(d);
+            var r = __collection.FindOne(Query.EQ("_id", d.Id));
+            Assert.Equal(d.Id, r.Id);
+            Assert.Equal(1, r.Data.Count);
+            Assert.Equal(1, r.Data["a.b"]);
         }
 
         [Fact]
@@ -215,7 +233,12 @@ public void TestHashtableDocumentRepresentationWithDollar()
             var json = d.ToJson();
             Assert.Equal(expected, json);
 
-            Assert.Throws<BsonSerializationException>(() => { __collection.Insert(d); });
+            __collection.RemoveAll();
+            __collection.Insert(d);
+            var r = __collection.FindOne(Query.EQ("_id", d.Id));
+            Assert.Equal(d.Id, r.Id);
+            Assert.Equal(1, r.Data.Count);
+            Assert.Equal(1, r.Data["$a"]);
         }
 
         [Fact]
@@ -226,7 +249,12 @@ public void TestHashtableDocumentRepresentationWithDot()
             var json = d.ToJson();
             Assert.Equal(expected, json);
 
-            Assert.Throws<BsonSerializationException>(() => { __collection.Insert(d); });
+            __collection.RemoveAll();
+            __collection.Insert(d);
+            var r = __collection.FindOne(Query.EQ("_id", d.Id));
+            Assert.Equal(d.Id, r.Id);
+            Assert.Equal(1, r.Data.Count);
+            Assert.Equal(1, r.Data["a.b"]);
         }
 
         [Fact]
@@ -254,7 +282,11 @@ public void TestHashtableDynamicRepresentationWithDollar()
             Assert.Equal(expected, json);
 
             __collection.RemoveAll();
-            Assert.Throws<BsonSerializationException>(() => __collection.Insert(d));
+            __collection.Insert(d);
+            var r = __collection.FindOne(Query.EQ("_id", d.Id));
+            Assert.Equal(d.Id, r.Id);
+            Assert.Equal(1, r.Data.Count);
+            Assert.Equal(1, r.Data["$a"]);
         }
 
         [Fact]
@@ -266,7 +298,11 @@ public void TestHashtableDynamicRepresentationWithDot()
             Assert.Equal(expected, json);
 
             __collection.RemoveAll();
-            Assert.Throws<BsonSerializationException>(() => __collection.Insert(d));
+            __collection.Insert(d);
+            var r = __collection.FindOne(Query.EQ("_id", d.Id));
+            Assert.Equal(d.Id, r.Id);
+            Assert.Equal(1, r.Data.Count);
+            Assert.Equal(1, r.Data["a.b"]);
         }
     }
 }