MongoDB integration

[koenbeuk]

Integrate MongoDB support into ExpressiveSharp, including the addition of MongoDB.Driver and Testcontainers.MongoDb packages. Implement a new queryable interface and related functionality to enable LINQ queries with expressive syntax for MongoDB collections. Include integration tests to verify the new features.

[codecov]

Codecov Report

❌ Patch coverage is 36.00000% with 64 lines in your changes missing coverage. Please review.

Files with missing lines	Patch %	Lines
...B/Extensions/ExpressiveQueryableMongoExtensions.cs	0.00%	49 Missing ⚠️
...oDB/Infrastructure/ExpressiveMongoQueryProvider.cs	53.33%	7 Missing ⚠️
...MongoDB/Infrastructure/ExpressiveMongoQueryable.cs	44.44%	3 Missing and 2 partials ⚠️
...rp.MongoDB/Extensions/MongoExpressiveExtensions.cs	83.33%	0 Missing and 2 partials ⚠️
...pressiveSharp.MongoDB/ExpressiveMongoCollection.cs	83.33%	0 Missing and 1 partial ⚠️

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[Copilot]

Pull request overview

Adds first-class MongoDB support to ExpressiveSharp by introducing a MongoDB-specific query provider/wrapper that expands [Expressive] members before MongoDB LINQ translation, plus a new integration test suite running against a containerized MongoDB instance.

Changes:

• Introduces ExpressiveSharp.MongoDB with an IMongoQueryProvider decorator and IExpressiveMongoQueryable<T> wrapper.
• Adds MongoDB-specific polyfill async stubs (generator-intercepted) and default transformer options tailored for MongoDB LINQ translation.
• Adds MongoDB integration tests + CI job using Testcontainers.

Reviewed changes

Copilot reviewed 22 out of 22 changed files in this pull request and generated 7 comments.

Show a summary per file

File	Description
tests/ExpressiveSharp.MongoDB.IntegrationTests/Tests/TransformerPipelineTests.cs	Validates transformer pipeline output is translatable by Mongo LINQ; includes custom options test.
tests/ExpressiveSharp.MongoDB.IntegrationTests/Tests/PolyfillInterceptorTests.cs	Verifies generator interception for delegate-based LINQ in Mongo queries.
tests/ExpressiveSharp.MongoDB.IntegrationTests/Tests/ExpressiveMongoQueryProviderTests.cs	Exercises provider-level [Expressive] expansion in select/where/orderby scenarios.
tests/ExpressiveSharp.MongoDB.IntegrationTests/Tests/ExpressiveMongoQueryableTests.cs	Ensures wrapper/provider types are preserved and Mongo-specific APIs still work.
tests/ExpressiveSharp.MongoDB.IntegrationTests/Tests/ExpressiveMongoCollectionTests.cs	Validates higher-level collection wrapper delegates CRUD and supports LINQ.
tests/ExpressiveSharp.MongoDB.IntegrationTests/Tests/EmbeddedDocumentTests.cs	Validates [Expressive] expansion works with embedded documents/null-conditional chains.
tests/ExpressiveSharp.MongoDB.IntegrationTests/Tests/AsyncMethodTests.cs	Validates Mongo async operations work through the delegate-lambda chain.
tests/ExpressiveSharp.MongoDB.IntegrationTests/Infrastructure/MongoTestBase.cs	Creates per-test DB, seeds embedded documents, and cleans up databases.
tests/ExpressiveSharp.MongoDB.IntegrationTests/Infrastructure/MongoContainerFixture.cs	Manages a MongoDB Testcontainers lifecycle at assembly scope.
tests/ExpressiveSharp.MongoDB.IntegrationTests/ExpressiveSharp.MongoDB.IntegrationTests.csproj	New MSTest project referencing MongoDB + Testcontainers + generator analyzer.
src/ExpressiveSharp.MongoDB/MongoExpressiveOptions.cs	Provides MongoDB-oriented default transformer pipeline.
src/ExpressiveSharp.MongoDB/Infrastructure/ExpressiveMongoQueryProvider.cs	Decorates IMongoQueryProvider to expand expressions before execution.
src/ExpressiveSharp.MongoDB/Infrastructure/ExpressiveMongoQueryable.cs	Wraps IQueryable<T> so chained operations keep the expressive provider.
src/ExpressiveSharp.MongoDB/IExpressiveMongoQueryable.cs	Marker interface for MongoDB queryables that support rewrite/interception.
src/ExpressiveSharp.MongoDB/Extensions/MongoExpressiveExtensions.cs	Entry points to wrap Mongo queryables/collections with expressive expansion.
src/ExpressiveSharp.MongoDB/Extensions/ExpressiveQueryableMongoExtensions.cs	Generator-intercepted async stubs targeting MongoQueryable.
src/ExpressiveSharp.MongoDB/ExpressiveMongoCollection.cs	Convenience wrapper around IMongoCollection<TDocument> exposing expressive LINQ.
src/ExpressiveSharp.MongoDB/ExpressiveSharp.MongoDB.csproj	New MongoDB integration project (adds MongoDB.Driver).
ExpressiveSharp.slnx	Adds new MongoDB projects to the solution.
Directory.Packages.props	Adds package versions for MongoDB.Driver and Testcontainers.MongoDb.
.github/workflows/ci.yml	Adds a dedicated MongoDB container test job.
.devcontainer/devcontainer.json	Adjusts Docker-in-Docker feature configuration.

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[Copilot]

GetEnumerator() delegates directly to _source, which executes the query using the underlying Mongo provider and bypasses ExpressiveMongoQueryProvider.Execute/ExecuteAsync (so [Expressive] expansion may not happen for synchronous enumeration like foreach / ToList()). Implement enumeration via the wrapper Provider (e.g., execute Expression through _provider) so execution always flows through the expanding provider.

Suggested change

	public IEnumerator<T> GetEnumerator() => _source.GetEnumerator();
	IEnumerator IEnumerable.GetEnumerator() => ((IEnumerable)_source).GetEnumerator();
	public IEnumerator<T> GetEnumerator()
	{
	var result = _provider.Execute<IEnumerable<T>>(Expression);
	return result.GetEnumerator();
	}
	IEnumerator IEnumerable.GetEnumerator() => GetEnumerator();

[Copilot]

MongoDB.Extensions.MongoExpressiveExtensions doesn’t exist in this repo (the extension is ExpressiveSharp.MongoDB.Extensions.MongoExpressiveExtensions). This will not compile; call the correct extension method/namespace (or just use Orders.AsExpressive(customOptions)).

Suggested change

	var customQuery = MongoDB.Extensions.MongoExpressiveExtensions.AsExpressive(
	var customQuery = ExpressiveSharp.MongoDB.Extensions.MongoExpressiveExtensions.AsExpressive(

[Copilot]

These .AsExpressive() calls will currently bind to ExpressiveSharp.Extensions.ExpressiveQueryableExtensions.AsExpressive (because ExpressiveSharp.MongoDB.Extensions isn’t imported), which won’t install ExpressiveMongoQueryProvider and will leave [Expressive] members unexpanded for Mongo translation. Import/use the MongoDB integration AsExpressive extension explicitly to ensure the provider decoration happens.