Projection tooling for Swift interop in .NET 10

[kotlarmilos]

Overview

This issue tracks the progress of implementing and shipping the projection tooling for .NET 10. The primary goal is to release the projection tooling as an experimental NuGet CLI capable of generating bindings for a specific set of Swift frameworks, as defined in the use cases. It should follow general principles outlined in the Swift interop proposal.

Currently, the projection tooling is available as an experimental NuGet CLI in dotnet-experimental feed.

Workstream: Swift language features

Based on the selected frameworks, the following Swift language features are in use:

• [Swift language features] Implement Swift structs in C# runtimelab#2822
• [Swift language features] Implement Swift generics support for structs runtimelab#2930
• [Swift language features] Implement Swift generics support for enums runtimelab#2931
• [Swift language features] Implement Swift async runtimelab#2837
• Built-in types
  • [Swift language features] Implement unsafe pointers in C# runtimelab#2832
  • [Swift language features] Implement Swift.String in C# runtimelab#2831
  • [Swift language features] Implement Swift.Array in C# runtimelab#2833
  • [Swift language features] Implement Swift.Set in C# runtimelab#2834
  • [Swift language features] Implement Swift.Optional in C# runtimelab#2929

Workstream: Swift runtime features

To support the mentioned language features, the following runtime features are required:

• [Swift runtime features] Implement Swift metadata runtimelab#2838
• [Swift runtime features] Implement Swift value witness tables support runtimelab#2840

Workstream: Projection tooling

To generate bindings, we need projection tooling that includes the following components (based on the current design):

• [Projection tooling] Implement type database runtimelab#2842
• [Projection tooling] Add symbols from dynamic library to type database runtimelab#2918

Workstream: Shipping

We need the following infrastructure:

• [Swift shipping] Create Swift.Bindings.Experimental and tooling NuGet packages in the dotnet-experimental feed runtimelab#2849
• [Swift shipping] Implement testing framework runtimelab#2850

Note

The projection tooling will be experimental in .NET 10.

Tagging subscribers to this area: @dotnet/area-meta
See info in area-owners.md if you want to be subscribed.

Issue Details

---

Description

This issue tracks the work for adapting the existing Binding Tools for Swift and shipping it as a product in .NET 9. The projection tooling consists of three main areas: Importing Swift into .NET, Exporting .NET to Swift, and distribution.

Below is a list of tasks that needs to be implemented. Please note that the breakdown of the issues does not impose hard deadlines. If some of the functionality does not get upstreamed for a particular preview version, this issue will be updated accordingly.

Tasks

.NET9 Preview 1

• Update documentation to specify tool's layout
• Update documentation to specify type representations
• Create a NuGet package for the BTfS
• Ensure that the NuGet package is shipped for supported platforms such as OSX and Apple mobile

.NET9 Preview 2

• Adapt the tool to work with the new runtime support
• Add Roslyn source generators to generate Swift metadata for selected assemblies

.NET9 Preview 3

TBD

Author:	kotlarmilos
Assignees:	kotlarmilos, stephen-hawley
Labels:	area-Meta, User Story
Milestone:	9.0.0

[stephen-hawley]

Might want to include "Update BTfS to run on .NET 7 and later" - I'm in the middle of that right now.