Hide IBsonReader settings

Author: papafe

src/MongoDB.Bson/IO/IBsonReader.cs

@@ -62,7 +62,7 @@ public interface IBsonReader : IDisposable
         /// <summary>
         /// Pops the settings.
         /// </summary>
-        void PopSettings();  //TODO Why do we have push and pop methods? They are not used. We should remove them.
+        void PopSettings(); //TODO Why do we have push and pop methods? They are not used. We should remove them.
 
         /// <summary>
         /// Pushes new settings for the reader.
@@ -246,14 +246,6 @@ public interface IBsonReader : IDisposable
         /// <param name="bookmark">The bookmark.</param>
         void ReturnToBookmark(BsonReaderBookmark bookmark);
 
-        //TODO I'm not sure why this was not already present, there is already an equivalent in IBsonWriter.
-        //We can also avoid adding this to the interface and casting all the occurrences of IBsonReader to BsonReader (the base class for all readers in our codebase).
-        //Of course this would be a problem if someone implements IBsonReader in a different way.
-        /// <summary>
-        /// Gets the settings of the reader.
-        /// </summary>
-        BsonReaderSettings Settings { get; }
-
         /// <summary>
         /// Skips the name (reader must be positioned on a name).
         /// </summary>
@@ -264,4 +256,13 @@ public interface IBsonReader : IDisposable
         /// </summary>
         void SkipValue();
     }
+
+    internal interface IBsonReaderInternal : IBsonReader
+    {
+        //TODO I'm not sure why this was not already present, there is already an equivalent in IBsonWriter.
+        /// <summary>
+        /// Gets the settings of the reader.
+        /// </summary>
+        BsonReaderSettings Settings { get; }
+    }
 }

src/MongoDB.Bson/Serialization/BsonDeserializationContext.cs

@@ -41,7 +41,13 @@ private BsonDeserializationContext(
             _allowDuplicateElementNames = allowDuplicateElementNames;
             _dynamicArraySerializer = dynamicArraySerializer;
             _dynamicDocumentSerializer = dynamicDocumentSerializer;
-            _serializationDomain = reader.Settings?.SerializationDomain ?? BsonSerializer.DefaultSerializationDomain;
+
+            if (reader is IBsonReaderInternal readerInternal)
+            {
+                _serializationDomain = readerInternal.Settings?.SerializationDomain;
+            }
+
+            _serializationDomain ??= BsonSerializer.DefaultSerializationDomain;
         }
 
         // public properties