MAUI and Nix

This is a cobbled-together and barely-working Nix flake in which it is possible to create and build a MAUI project.

Steps to demonstrate the proof of concept

1. nix develop
2. dotnet new maui --name MauiTest && cd MauiTest
3. Since I haven't included the Android dependencies (they are currently commented in, but the darwin-aarch64 architecture lacks an Android SDK in nixpkgs), I have to rm -r Platforms/Android && sed -i 's/net6.0-android//g' MauiTest.csproj. You may need to do some work to get the Android SDK.
4. dotnet build.

Gotchas

Since I haven't done much work to encode the dependencies between workloads, the only way you'll know if you've missed out a required workload from the list you install in your flake is if the build fails. Moreover, the build message is extremely unhelpful: even if you've installed the maccatalyst workload, for example, if you've missed out the manifest.microsoft-net-runtime-maccatalyst-7_0_2 workload (which is a dependency) and you try and build a MacCatalyst app, you're liable to get a message that just says the maccatalyst workload must be installed. In future, we should actually encode these dependencies in Nix and resolve them properly.

How to generate the manifest files

The accompanying F# project is used to generate the workload-manifest-list.nix and workload-manifest-contents.nix files. You call it with:

dotnet run --project maui-dotnet-flake.fsproj 6.0.301 /Users/patrick/Documents/GitHub/maui-dotnet-flake

Here the 6.0.301 is the SDK version for which we are requesting a complete manifest of available SDK workloads, and the output path is the path where we write the manifest .nix files.

Note that this will download a lot of NuGet packages. By default it will do so into /tmp/pkgs (see the start of Program.fs for the local cache logic), but this was only so that my local development loop was shortened; there is no consistency checking of any kind (so e.g. if you change SDK versions, the cache is not invalidated), so you may wish to flip LOCAL_CACHE to false.

workload-manifest-contents.nix

This is a complete listing of each .NET workload you can install, the dependent NuGet packages for each workload, and the alias resolutions for per-platform packages.

workload-manifest-list.nix

This is a complete listing of each NuGet package that defines an SDK manifest, but with no dependencies. This is required because .NET somehow knows which manifests are meant to be there, even if you're never going to use them, and it complains unless all these packages are present in its sdk-manifests folder (which they are by default, except that we're upgrading them from the default in the course of installing a workload).

Known bugs

• There is likely something wrong with the composition of SDK workloads. I've seen the current setup stop working entirely if I remove the android manifest, although oddly enough my most recent attempt Just Worked.
• You have to just magically know which workloads you need to install. In fact the dependency information is encoded in the NuGet packages, but I have not done anything to help you there; you simply have to try it with [manifest.maui] and see it fail so that you know you also need e.g. [manifest.maui manifest.microsoft-net-runtime-android].