LeXtudio.Metadata.Mutable — a small, reusable library for reading, mutating, and writing .NET assembly metadata and IL. This project consolidates mutable metadata/IL model code so tools like Obfuscar and other consumers can reuse a single, well-tested implementation.

• Purpose: Provide a mutable object model for metadata and method bodies plus reader/writer implementations built on System.Reflection.Metadata.
• Primary project: src/LeXtudio.Metadata.Mutable.
• Supported TFMs: net8.0 (primary) and net462 (legacy compatibility).

• Mutable metadata and IL model (types, methods, fields, instructions).
• MutableAssemblyReader / MutableAssemblyWriter for PE/metadata read/write.
• Designed for reuse across multiple tooling projects; lightweight compatibility shims are provided in Support.
• Tests demonstrating round-trip behavior are included.

Currently used in both Obfuscar and WXSG projects.

Add the NuGet package from nuget.org (preferred):

dotnet add <your-project>.csproj package LeXtudio.Metadata.Mutable

If you need to test locally before publishing, pack the library and add the local folder as a package source:

dotnet pack src/LeXtudio.Metadata.Mutable/LeXtudio.Metadata.Mutable.csproj -c Release

dotnet nuget add source "src\LeXtudio.Metadata.Mutable\bin\Release" -n local-pkgs

dotnet add <your-project>.csproj package LeXtudio.Metadata.Mutable --source local-pkgs

Build the library (example, net8.0):

dotnet build src/LeXtudio.Metadata.Mutable/LeXtudio.Metadata.Mutable.csproj -f net8.0

Run the tests:

dotnet test tests/LeXtudio.Metadata.Mutable.Tests/LeXtudio.Metadata.Mutable.Tests.csproj

• Reference the package. Use the public API surface under the LeXtudio.Metadata.Mutable namespace — for example the reader/writer classes (MutableAssemblyReader, MutableAssemblyWriter), MutableTypeSystem, and PersistedAssemblyBuilder.
• Concrete usage examples are available in the test projects; see:
  • tests/LeXtudio.Metadata.Mutable.Tests/MutableAssemblyWriterRoundTripTests.cs
  • tests/LeXtudio.Metadata.Mutable.Tests/RoundtripTests.cs

Design notes and rationale: docs/design.md

• net8.0 (primary)
• net462 (legacy compatibility)

Note: Some tests exercise net9.0 features and are located under the tests folder.

• Fork, implement changes in a feature branch, and open a pull request.
• Run the relevant tests locally (dotnet test ...) and include tests for new behavior.
• Keep changes focused and add documentation when you change public APIs.

This repository is licensed under the MIT License — see LICENSE.