EF-76: Flow EF metadata down through CreateGetValueExpression (#240)

[ajcvickers]

• EF-76: Flow EF metadata down through CreateGetValueExpression

That is, the IProperty or INavigation associated with the access. Types, requiredness, type-mappings, etc. are then obtained from the property.

An alias is passed in if the name in the BSON document is different from the mapped element name for the property.

• Updates based on co-pilot review.

[Copilot]

Pull Request Overview

This PR refactors the BSON binding system to flow Entity Framework metadata through the CreateGetValueExpression method, replacing primitive parameters with rich metadata objects. The core change passes an IProperty or INavigation object that contains type information, nullability, and type mappings instead of relying on separate parameters.

Key changes:

• Modified CreateGetValueExpression to accept IPropertyBase instead of separate name, type, and requirement parameters
• Updated GetPropertyValue and GetPropertySerializationInfo methods to accept an alias parameter for field name mapping
• Removed the root entity type parameter from MongoProjectionBindingRemovingExpressionVisitor constructor

Reviewed Changes

Copilot reviewed 8 out of 8 changed files in this pull request and generated 1 comment.

Show a summary per file

File	Description
BsonBinding.cs	Core refactoring to use IPropertyBase metadata instead of primitive parameters
MongoProjectionBindingRemovingExpressionVisitor.cs	Updated to work with new metadata-driven approach and removed root entity type dependency
BsonSerializerFactory.cs	Added alias parameter support for property serialization
EntitySerializer.cs	Updated method call to include null alias parameter
MongoUpdate.cs	Updated method call to include null alias parameter
BsonBindingTests.cs	Updated test method calls to include null alias parameter
NorthwindMiscellaneousQueryMongoTest.cs	Updated test assertions to reflect improved error handling

Comments suppressed due to low confidence (1)

src/MongoDB.EntityFrameworkCore/Query/Visitors/MongoProjectionBindingRemovingExpressionVisitor.cs:1

• Consider using a more specific exception type or converting this to a runtime check with an appropriate exception. Debug assertions are removed in release builds, potentially allowing invalid states to proceed.

/* Copyright 2023-present MongoDB Inc.

---

_{Tip: Customize your code reviews with copilot-instructions.md. Create the file or learn how to get started.}

[Copilot]

Remove commented-out code that is not currently used. If this functionality is needed for future development, it should be tracked in an issue rather than left as commented code.

Suggested change

	// TODO: handle more nesting; not currently used.
	//RootReferenceExpression => CreateGetValueExpression(DocParameter, null, required, typeof(BsonDocument), propertyBase: propertyBase, declaredType: propertyBase!.DeclaringType),
	//ObjectAccessExpression docAccessExpression => CreateGetValueExpression(docAccessExpression.AccessExpression, docAccessExpression.Name, required, typeof(BsonDocument), propertyBase: propertyBase, declaredType: propertyBase!.DeclaringType),
	// TODO: handle more nesting in future.