Proof of concept (#1)

.gitignore

@@ -0,0 +1,11 @@
+bin/
+obj/
+/packages/
+riderModule.iml
+/_ReSharper.Caches/
+.idea/
+*.user
+*.DotSettings
+
+/result
+/.profile*

MauiDotnetFlake/Async.fs

@@ -0,0 +1,10 @@
+namespace MauiDotnetFlake
+
+[<RequireQualifiedAccess>]
+module Async =
+
+    let map<'a, 'b> (f : 'a -> 'b) (x : Async<'a>) : Async<'b> =
+        async {
+            let! x = x
+            return f x
+        }

MauiDotnetFlake/Domain.fs

@@ -0,0 +1,159 @@
+namespace MauiDotnetFlake
+
+open System
+open System.Collections.Immutable
+open System.ComponentModel
+open Newtonsoft.Json
+
+type [<JsonConverter (typeof<PackKeyJsonConverter>) ; TypeConverter (typeof<PackKeyTypeConverter>)>] PackKey =
+    | PackKey of string
+    /// Human-readable round-trip representation
+    override this.ToString () =
+        match this with
+        | PackKey p -> p
+and PackKeyJsonConverter () =
+    inherit JsonConverter<PackKey> ()
+    override _.ReadJson (reader : JsonReader, objectType : Type, _existingValue : PackKey, _ : bool, _ : JsonSerializer) =
+        if objectType <> typeof<PackKey> then
+            failwith $"Unexpected object type for pack key: {objectType}"
+        let value = reader.Value |> unbox<string>
+        PackKey value
+    override _.WriteJson (writer : JsonWriter, PackKey key, _ : JsonSerializer) : unit =
+        writer.WriteValue key
+and PackKeyTypeConverter () =
+    inherit TypeConverter ()
+    override _.CanConvertFrom (_, t : Type) : bool =
+        t = typeof<string>
+    override _.ConvertFrom (_, _, v : obj) : obj =
+        v |> unbox<string> |> PackKey |> box
+
+type [<JsonConverter (typeof<WorkloadKeyJsonConverter>) ; TypeConverter (typeof<WorkloadKeyTypeConverter>)>] WorkloadKey =
+    | WorkloadKey of string
+and WorkloadKeyJsonConverter () =
+    inherit JsonConverter<WorkloadKey> ()
+    override _.ReadJson (reader : JsonReader, objectType : Type, _existingValue : _, _ : bool, _ : JsonSerializer) : WorkloadKey =
+        if objectType <> typeof<WorkloadKey> then
+            failwith $"Unexpected object type for workload key: {objectType}"
+        let value = reader.Value |> unbox<string> |> WorkloadKey
+        value
+    override _.WriteJson (_ : JsonWriter, _ : WorkloadKey, _ : JsonSerializer) : unit =
+        failwith "do not call"
+and WorkloadKeyTypeConverter () =
+    inherit TypeConverter ()
+    override _.CanConvertFrom (_, t : Type) : bool =
+        t = typeof<string>
+    override _.ConvertFrom (_, _, v : obj) : obj =
+        v |> unbox<string> |> WorkloadKey |> box
+
+type WorkloadManifest =
+    {
+        /// e.g. ".NET MAUI SDK for all platforms"
+        Description : string
+        /// e.g. ["maui-blazor"]
+        Extends : WorkloadKey list
+        /// e.g. ["Microsoft.MAUI.Dependencies"]
+        Packs : PackKey list
+    }
+
+type [<JsonConverter (typeof<PackManifestKindJsonConverter>) ; TypeConverter (typeof<PackManifestKindTypeConverter>)>] PackManifestKind =
+    | Library
+    | Framework
+    | Sdk
+    | Template
+    static member Parse (value : string) =
+        match value.ToLowerInvariant () with
+        | "library" -> PackManifestKind.Library
+        | "sdk" -> PackManifestKind.Sdk
+        | "framework" -> PackManifestKind.Framework
+        | "template" -> PackManifestKind.Template
+        | _ -> failwith $"Unexpected value in pack manifest kind: {value}"
+    member this.ToInt =
+        match this with
+        | Library -> 2
+        | Framework -> 1
+        | Sdk -> 0
+        | Template -> 3
+    override this.ToString () =
+        match this with
+        | Library -> "library"
+        | Framework -> "framework"
+        | Sdk -> "sdk"
+        | Template -> "template"
+
+and PackManifestKindJsonConverter () =
+    inherit JsonConverter<PackManifestKind> ()
+    override _.ReadJson (reader : JsonReader, objectType : Type, _existingValue : PackManifestKind, _ : bool, _ : JsonSerializer) : PackManifestKind =
+        if objectType <> typeof<PackManifestKind> then
+            failwith $"Unexpected object type for pack manifest kind: {objectType}"
+        PackManifestKind.Parse (reader.Value |> unbox<string>)
+    override _.WriteJson (w : JsonWriter, v : PackManifestKind, _ : JsonSerializer) : unit =
+        w.WriteValue v.ToInt
+and PackManifestKindTypeConverter () =
+    inherit TypeConverter ()
+    override _.CanConvertFrom (_, t : Type) : bool =
+        t = typeof<string>
+    override _.CanConvertTo (_, t : Type) : bool =
+        t = typeof<int>
+    override _.ConvertFrom (_, _, v : obj) : obj =
+        v |> unbox<string> |> PackManifestKind.Parse |> box
+    override _.ConvertTo (_, _, v : obj, _destType : Type) : obj =
+        (v |> unbox<PackManifestKind>).ToInt
+
+type PackManifest =
+    {
+        Kind : PackManifestKind
+        Version : Version
+        /// Map of "win-x64": "nuget-package-name", for example
+        [<JsonProperty "alias-to">]
+        AliasTo : ImmutableDictionary<string, string>
+    }
+
+type Manifest =
+    {
+        Version : Version
+        Workloads : Map<WorkloadKey, WorkloadManifest>
+        Packs : Map<PackKey, PackManifest>
+    }
+
+type Registration =
+    {
+        Id : PackKey
+        Version : Version
+        Kind : PackManifestKind
+        ResolvedPackageId : PackKey
+        Path : string
+        IsStillPacked : bool
+    }
+
+type HashString =
+    | HashString of string
+    override this.ToString () =
+        match this with
+        | HashString s -> s
+
+/// A NuGet package such as "Microsoft.Maui.Controls.Ref.android".
+type Pack =
+    {
+        Name : PackKey
+        Version : Version
+        Hash : HashString
+        Type : PackManifestKind
+    }
+
+type WorkloadCollation =
+    {
+        /// The NuGet package that defines the manifest for this workload.
+        Package : string
+        /// The version of the NuGet package that defines the manifest for this workload.
+        Version : string
+        /// The SHA256 of the NuGet package that defines the manifest for this workload.
+        Hash : HashString
+        /// The rendered manifest of this workload.
+        Manifest : Manifest
+    }
+
+type Platform =
+    | Platform of string
+    override this.ToString () =
+        match this with
+        | Platform p -> p

MauiDotnetFlake/Hash.fs

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+namespace MauiDotnetFlake
+
+open System
+open System.IO
+open System.Security.Cryptography
+
+[<RequireQualifiedAccess>]
+module Hash =
+    let getAsync (stream : Stream) =
+        async {
+            use c = SHA256.Create ()
+            let! ct = Async.CancellationToken
+            stream.Seek (0, SeekOrigin.Begin) |> ignore
+            let! hash = c.ComputeHashAsync (stream, ct) |> Async.AwaitTask
+            return
+                hash
+                |> Convert.ToBase64String
+                |> HashString
+        }

MauiDotnetFlake/Map.fs

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+namespace MauiDotnetFlake
+
+[<RequireQualifiedAccess>]
+module Map =
+
+    let union<'k, 'v when 'k : comparison> (merge : 'v -> 'v -> 'v) (m1 : Map<'k, 'v>) (m2 : Map<'k, 'v>) =
+        (m1, m2)
+        ||> Map.fold (fun acc k v ->
+            acc
+            |> Map.change k (function
+                | None -> Some v
+                | Some v2 -> Some (merge v v2)
+            )
+        )
+

MauiDotnetFlake/Maui.sln

@@ -0,0 +1,16 @@
+
+Microsoft Visual Studio Solution File, Format Version 12.00
+Project("{F2A71F9B-5D33-465A-A702-920D77279786}") = "maui-dotnet-flake", "maui-dotnet-flake.fsproj", "{5BE1A4A9-5DB9-4D3D-AC4D-EEBC0009257F}"
+EndProject
+Global
+	GlobalSection(SolutionConfigurationPlatforms) = preSolution
+		Debug|Any CPU = Debug|Any CPU
+		Release|Any CPU = Release|Any CPU
+	EndGlobalSection
+	GlobalSection(ProjectConfigurationPlatforms) = postSolution
+		{5BE1A4A9-5DB9-4D3D-AC4D-EEBC0009257F}.Debug|Any CPU.ActiveCfg = Debug|Any CPU
+		{5BE1A4A9-5DB9-4D3D-AC4D-EEBC0009257F}.Debug|Any CPU.Build.0 = Debug|Any CPU
+		{5BE1A4A9-5DB9-4D3D-AC4D-EEBC0009257F}.Release|Any CPU.ActiveCfg = Release|Any CPU
+		{5BE1A4A9-5DB9-4D3D-AC4D-EEBC0009257F}.Release|Any CPU.Build.0 = Release|Any CPU
+	EndGlobalSection
+EndGlobal

MauiDotnetFlake/Program.fs

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+namespace MauiDotnetFlake
+
+open System
+open System.Collections.Generic
+open System.IO
+open System.IO.Compression
+open System.Net.Http
+open Newtonsoft.Json
+
+module Program =
+    [<Literal>]
+    let LOCAL_CACHE = true
+
+    let source =
+        if LOCAL_CACHE then
+            let dir = DirectoryInfo "/tmp/pkgs/"
+            if not dir.Exists then dir.Create ()
+            dir.EnumerateFiles ("*.nupkg", SearchOption.AllDirectories)
+            |> Seq.map (fun fi -> fi.Name.Substring(0, fi.Name.Length - ".nupkg".Length).ToLowerInvariant(), fi)
+            |> readOnlyDict
+        else
+            Dictionary ()
+            :> IReadOnlyDictionary<_, _>
+
+    let fetchZip (client : HttpClient) (uri : Uri) : Stream Async =
+        async {
+            let! ct = Async.CancellationToken
+            try
+                let! s = Async.AwaitTask (client.GetStreamAsync (uri, ct))
+                return s
+            with
+            | e ->
+                return raise (AggregateException(uri.ToString (), e))
+        }
+
+    let rec waitForReady (file : FileInfo) : Async<Stream> =
+        async {
+            try
+                return file.OpenRead () :> Stream
+            with
+            | e ->
+                if e.Message.Contains "is being used by another process" then
+                    do! Async.Sleep (TimeSpan.FromSeconds 5.0)
+                    return! waitForReady file
+                else
+                    return raise e
+        }
+
+    let fetchPackageStream (client : HttpClient) (PackKey packKey) (version : Version) : Async<Stream> =
+        let download =
+            lazy
+                let uri = Uri $"https://www.nuget.org/api/v2/package/{packKey}/{version}"
+                async {
+                    try
+                        use! zip = fetchZip client uri
+                        let destFile = $"/tmp/pkgs/{packKey.ToLowerInvariant()}.{version}.nupkg"
+                        try
+                            do
+                                use dest = File.OpenWrite destFile
+                                zip.CopyTo dest
+                            return File.OpenRead destFile :> Stream
+                        with
+                        | e ->
+                            if e.Message.Contains "is being used by another process" then
+                                return! waitForReady (FileInfo destFile)
+                            else
+                                return raise e
+                    with
+                    | e ->
+                        return raise (AggregateException(uri.ToString (), e))
+                }
+
+        match source.TryGetValue $"{packKey.ToLowerInvariant()}.{version}" with
+        | true, v ->
+            async {
+                let s = v.OpenRead ()
+                return s
+            }
+        | false, _ ->
+
+        match source.TryGetValue $"{packKey.ToLowerInvariant()}" with
+        | true, v ->
+            if v.Directory.Name = version.ToString () then
+                async {
+                    let s = v.OpenRead ()
+                    return s
+                }
+            else
+                //failwith $"Unexpected version, wanted {version.ToString()} but cached {v.Directory.Name}"
+                download.Force ()
+        | false, _ ->
+            download.Force ()
+
+    let fetchPackageHash (client : HttpClient) =
+        // Not necessary, but speeds it up a fair bit
+        let memo = System.Collections.Concurrent.ConcurrentDictionary<PackKey * Version, HashString> ()
+        fun (packKey : PackKey) (version : Version) ->
+            async {
+                match memo.TryGetValue ((packKey, version)) with
+                | true, v -> return v
+                | false, _ ->
+                use! stream = fetchPackageStream client packKey version
+                let! answer = Hash.getAsync stream
+                memo.TryAdd ((packKey, version), answer) |> ignore
+                return answer
+            }
+
+    let fetchManifest' (contents : Stream) : Manifest Async =
+        async {
+            use arch = new ZipArchive (contents)
+            let deps = arch.GetEntry "data/WorkloadManifest.json"
+            let! entry =
+                async {
+                    use entry = new StreamReader (deps.Open ())
+                    return! entry.ReadToEndAsync () |> Async.AwaitTask
+                }
+            return JsonConvert.DeserializeObject<Manifest> entry
+        }
+
+    /// Download the specified nupkg and parse out the dependencies it implies.
+    let fetchManifest (manifest : FileInfo) : Manifest Async =
+        async {
+            use s = manifest.OpenRead ()
+            return! fetchManifest' s
+        }
+
+    let flatten (client : HttpClient) (workloadName : WorkloadKey option) (manifest : Manifest) : State Async =
+        manifest.Packs
+        |> Map.toSeq
+        |> Seq.collect (fun (packKey, packManifest) ->
+            match packManifest.AliasTo with
+            | null ->
+                Seq.singleton None
+            | map ->
+                map
+                |> Seq.map (fun (KeyValue(platform, pack)) -> Some (Platform platform, PackKey pack))
+            |> Seq.map (fun platform ->
+                match platform with
+                | None ->
+                    async {
+                        let! packageHash = fetchPackageHash client packKey packManifest.Version
+                        return
+                            None,
+                            {
+                                Name = packKey
+                                Hash = packageHash
+                                Version = packManifest.Version
+                                Type = packManifest.Kind
+                            }
+                    }
+                | Some (platform, resolvedPack) ->
+                    async {
+                        let! packageHash = fetchPackageHash client resolvedPack packManifest.Version
+                        return
+                            Some (platform, packKey),
+                            {
+                                Name = resolvedPack
+                                Hash = packageHash
+                                Version = packManifest.Version
+                                Type = packManifest.Kind
+                            }
+                    }
+            )
+        )
+        |> Async.Parallel
+        |> Async.map (Array.fold (fun state (platform, pack)->
+            match platform with
+            | None ->
+                State.addPack pack state
+            | Some (platform, beforeResolution) ->
+                State.addAlias platform beforeResolution pack state
+            ) (State.Empty workloadName))
+
+    let dotnet =
+        Path.Combine (typeof<int>.Assembly.Location, "..", "..", "..", "..", "bin", "dotnet")
+        |> FileInfo
+
+    let allAvailableWorkloads (sdkVersion : string) : Async<_> =
+        async {
+            let psi = System.Diagnostics.ProcessStartInfo (dotnet.FullName, Arguments = $"workload update --print-download-link-only --sdk-version {sdkVersion}")
+            psi.RedirectStandardError <- true
+            psi.RedirectStandardOutput <- true
+            use pr = new System.Diagnostics.Process()
+            pr.StartInfo <- psi
+            if not (pr.Start ()) then
+                failwith $"failed to start {dotnet}"
+            let! ct = Async.CancellationToken
+            do! Async.AwaitTask (pr.WaitForExitAsync ct)
+            let output = pr.StandardOutput.ReadToEnd ()
+
+            match output.Split("==") with
+            | [| _ ; "allPackageLinksJsonOutputStart" ; desired ; "allPackageLinksJsonOutputEnd" ; "\n" |] ->
+                return
+                    System.Text.Json.JsonSerializer.Deserialize<string list> desired
+                    |> List.map (fun uri ->
+                        match uri.Split "/" with
+                        | [| "https:" ; "" ; "api.nuget.org" ; "v3-flatcontainer" ; package ; version ; _path |] ->
+                            {| Package = package ; Version = version |}, Uri uri
+                        | _ -> failwith $"Unrecognised URL format: {uri}"
+                    )
+                    |> Map.ofList
+            | _ ->
+                return failwith $"Unexpected formatting: {output}"
+        }
+
+    let requiredWorkloads (w : WorkloadKey) (m : Manifest) : WorkloadKey Set =
+        let rec go (toAcc : WorkloadKey list) (results : WorkloadKey Set) =
+            match toAcc with
+            | [] -> results
+            | x :: toAcc ->
+                match Map.tryFind x m.Workloads with
+                | None ->
+                    go toAcc (Set.add x results)
+                | Some found ->
+                    if Object.ReferenceEquals (null, found.Extends) then
+                        go toAcc results
+                    else
+                        go (found.Extends @ toAcc) results
+        go [w] Set.empty
+
+
+    /// Find the manifests which define a given WorkloadKey.
+    let collate
+        (manifests : seq<WorkloadCollation>)
+        : Map<WorkloadKey, WorkloadCollation>
+        =
+        manifests
+        |> Seq.collect (fun collation ->
+            collation.Manifest.Workloads
+            |> Map.toSeq
+            |> Seq.map (fun (workload, _manifest) ->
+                workload, collation
+            )
+        )
+        |> Seq.groupBy fst
+        |> Seq.map (fun (key, values) ->
+            // Here is the assertion that each WorkloadKey is defined in exactly one workload
+            key, Seq.map snd values |> Seq.exactlyOne
+        )
+        |> Map.ofSeq
+
+    /// Render this workload as Nix, and also return our dependency workloads
+    let renderWorkload
+        (client : HttpClient)
+        (allAvailableWorkloads : Map<WorkloadKey, WorkloadCollation>)
+        (desiredWorkload : WorkloadKey)
+        : Async<NixInfo * WorkloadKey Set>
+        =
+        let collation =
+            match Map.tryFind desiredWorkload allAvailableWorkloads with
+            | None -> failwith $"You gave us {desiredWorkload} but there's no workload with that name"
+            | Some collation -> collation
+
+        let requiredWorkloads = requiredWorkloads desiredWorkload collation.Manifest
+        async {
+            let! flattened = flatten client (Some desiredWorkload) collation.Manifest
+            return State.toNix collation flattened, requiredWorkloads
+        }
+
+    let collectAllRequiredWorkloads
+        (client : HttpClient)
+        (allAvailableWorkloads : Map<WorkloadKey, WorkloadCollation>)
+        : Async<NixInfo>
+        =
+        let rec go (required : Set<WorkloadKey>) (state : _) =
+            async {
+                if required.IsEmpty then
+                    return state
+                else
+                    let desiredWorkload, rest = required.MaximumElement, Set.remove required.MaximumElement required
+                    // TODO - record the _required dependencies between workloads somehow, so that we can
+                    // consume them in Nix space
+                    let! thisTop, _required = renderWorkload client allAvailableWorkloads desiredWorkload
+                    return! go rest (NixInfo.merge state thisTop)
+            }
+
+        go (Map.keys allAvailableWorkloads |> Set.ofSeq) NixInfo.empty
+
+    [<EntryPoint>]
+    let main argv =
+        // e.g. "6.0.301", "/Users/patrick/Documents/GitHub/maui-dotnet-flake"
+        let sdkVersion, outputDir =
+            match argv with
+            | [| ver; outputDir |] -> ver, DirectoryInfo outputDir
+            | _ ->
+                argv
+                |> String.concat " "
+                |> failwithf "bad args: %s"
+
+        use client = new HttpClient ()
+
+        async {
+            let! allAvailableWorkloads = allAvailableWorkloads sdkVersion
+            let! allAvailableWorkloads =
+                allAvailableWorkloads
+                |> Map.toSeq
+                |> Seq.map (fun (ident, uri) ->
+                    async {
+                        let! ct = Async.CancellationToken
+                        use! s = Async.AwaitTask (client.GetStreamAsync uri)
+                        use ms = new MemoryStream ()
+                        do! Async.AwaitTask (s.CopyToAsync (ms, ct))
+                        let! hash = Hash.getAsync ms
+                        ms.Seek (0, SeekOrigin.Begin) |> ignore
+                        let! manifest = fetchManifest' ms
+                        return
+                            {
+                                Package = ident.Package
+                                Version = ident.Version
+                                Hash = hash
+                                Manifest = manifest
+                            }
+                    }
+                )
+                |> Async.Parallel
+            let allAvailableWorkloads = collate allAvailableWorkloads
+
+            let! nixInfo = collectAllRequiredWorkloads client allAvailableWorkloads
+            let writeContents = File.WriteAllTextAsync (Path.Combine (outputDir.FullName, "workload-manifest-contents.nix"), nixInfo |> NixInfo.toString)
+
+            let stripVersion (s : string) =
+                s.Substring (0, s.LastIndexOf '-')
+
+            let stripManifest (s : string) =
+                if s.EndsWith (".Manifest", StringComparison.InvariantCultureIgnoreCase) then
+                    s.Substring (0, s.Length - ".Manifest".Length)
+                else
+                    failwith $"{s} didn't end with .Manifest"
+
+            let allManifests =
+                allAvailableWorkloads
+                |> Map.values
+                |> Seq.distinctBy (fun collation -> collation.Package, collation.Version)
+                |> Seq.map (fun collation ->
+                    $"""{{
+  pname = "{collation.Package |> stripVersion |> stripManifest}";
+  version = "{collation.Version}";
+  src = fetchNuGet {{
+    version = "{collation.Version}";
+    hash = "sha256-{collation.Hash}";
+    pname = "{collation.Package}";
+  }};
+  workloadPacks = [];
+}}"""
+                )
+                |> String.concat "\n"
+                |> sprintf "fetchNuGet: [\n%s\n]"
+            let writeManifestList = File.WriteAllTextAsync (Path.Combine (outputDir.FullName, "workload-manifest-list.nix"), allManifests)
+
+            do! Async.AwaitTask writeContents
+            do! Async.AwaitTask writeManifestList
+
+            return 0
+        }
+        |> Async.RunSynchronously

MauiDotnetFlake/State.fs

@@ -0,0 +1,192 @@
+namespace MauiDotnetFlake
+
+type State =
+    {
+        Packs : Map<PackKey, Pack>
+        WorkloadName : WorkloadKey option
+        /// A map of before-alias-resolution to the available resolutions.
+        Aliases : Map<PackKey, Map<Platform, Pack>>
+    }
+    static member Empty (workloadName : WorkloadKey option) : State =
+        {
+            Packs = Map.empty
+            WorkloadName = workloadName
+            Aliases = Map.empty
+        }
+
+type NixName =
+    private
+    | NixName of string
+    override this.ToString () =
+        match this with
+        | NixName s -> s
+
+    static member Make (s : string) =
+        s.Replace(".", "")
+        |> NixName
+
+    static member Make (PackKey s) =
+        s.Replace(".", "")
+        |> NixName
+
+type NixExpression =
+    | NixExpression of string
+    override this.ToString () =
+        match this with
+        | NixExpression s -> s
+
+type NixInfo =
+    {
+        Workloads : Map<NixName, NixExpression>
+        Packs : Map<NixName, NixExpression>
+        Aliases : Map<PackKey, Map<Platform, PackKey>>
+    }
+    override this.ToString () =
+        let workloads =
+            this.Workloads
+            |> Map.toSeq
+            |> Seq.map (fun (nixName, body) -> $"{nixName} = {body}")
+            |> String.concat "\n"
+        let packs =
+            this.Packs
+            |> Map.toSeq
+            |> Seq.map (fun (nixName, body) -> $"{nixName} = {body}")
+            |> String.concat "\n"
+        let aliases =
+            this.Aliases
+            |> Map.toSeq
+            |> Seq.map (fun (unAliased, resolutions) ->
+                let resolveMap =
+                    resolutions
+                    |> Map.toSeq
+                    |> Seq.map (fun (platform, resolved) ->
+                        $"\"{platform}\" = {NixName.Make resolved};"
+                    )
+                    |> String.concat "\n"
+                    |> sprintf "{%s}"
+                $"{NixName.Make unAliased} = {resolveMap};"
+            )
+            |> String.concat "\n"
+        $"{workloads}\n{packs}\n{aliases}"
+
+[<RequireQualifiedAccess>]
+module NixInfo =
+    let empty =
+        {
+            Aliases = Map.empty
+            Workloads = Map.empty
+            Packs = Map.empty
+        }
+
+    let private assertEqual<'a when 'a : equality> (x : 'a) (y : 'a) : 'a =
+        if x = y then x else failwith $"duplicate found: {x}\n{y}\n-----\n"
+
+    let merge (n1 : NixInfo) (n2 : NixInfo) : NixInfo =
+        let workloads = Map.union assertEqual n1.Workloads n2.Workloads
+        let packs = Map.union assertEqual n1.Packs n2.Packs
+        let aliases = Map.union (Map.union assertEqual) n1.Aliases n2.Aliases
+        {
+            Workloads = workloads
+            Packs = packs
+            Aliases = aliases
+        }
+
+    let toString (n : NixInfo) : string =
+        $"""{{ buildDotnetWorkload, fetchNuGet, buildDotnetPack }}: rec {{
+{n}
+}}"""
+
+[<RequireQualifiedAccess>]
+module State =
+    let addPack (f : Pack) (s : State) =
+        { s with
+            Packs = s.Packs |> Map.add f.Name f
+        }
+    let addAlias (platform : Platform) (beforeAliasResolution : PackKey) (resolved : Pack) (s : State) =
+        { s with
+            Aliases =
+                s.Aliases
+                |> Map.change
+                    beforeAliasResolution
+                    (function
+                        | None -> Map.ofList [platform, resolved] |> Some
+                        | Some existing -> existing |> Map.add platform resolved |> Some
+                    )
+        }
+
+    let chopEnd (chop : string) (s : string) =
+        if s.EndsWith chop then
+            s.Substring (0, s.Length - chop.Length)
+        else
+            failwith "chop failed to chop"
+
+    let toNix
+        (collation : WorkloadCollation)
+        (state : State)
+        : NixInfo
+        =
+        // TODO fix domain
+        let workloadName =
+            Option.get state.WorkloadName
+            |> fun (WorkloadKey s) -> s
+            |> NixName.Make
+        let spaces = "    "
+        let workloadPacks =
+            state.Packs.Values
+            |> Seq.map (fun f -> f.Name)
+            |> Seq.map NixName.Make
+            |> Seq.map string<NixName>
+            |> Seq.sort
+            |> String.concat $"\n{spaces}"
+        let aliases =
+            state.Aliases.Keys
+            |> Seq.map NixName.Make
+            |> Seq.map string<NixName>
+            |> Seq.sort
+            |> String.concat $"\n{spaces}"
+
+        let primary =
+            //$"""buildDotnetWorkload (sdkVersion: rec {{
+            $"""rec {{
+  pname = "{workloadName}";
+  version = "{collation.Manifest.Version}";
+  src = fetchNuGet {{
+    pname = "{collation.Package}";
+    inherit version;
+    hash = "sha256-{collation.Hash}";
+  }};
+  workloadName = "{workloadName}";
+  workloadPacks = [
+{spaces}{workloadPacks}
+{spaces}{aliases}
+  ];
+}};"""
+        let primary = NixExpression primary
+
+        let secondaries =
+            state.Packs.Values
+            |> Seq.append (state.Aliases.Values |> Seq.collect (fun p -> p.Values))
+            |> Seq.sortBy (fun p -> p.Name)
+            |> Seq.map (fun l ->
+                let (PackKey name) = l.Name
+                let nixName = NixName.Make name
+                let output = $"""buildDotnetPack rec {{
+  pname = "{name}";
+  version = "{l.Version}";
+  kind = "{l.Type.ToString ()}";
+  src = fetchNuGet {{
+    inherit pname version;
+    hash = "sha256-{l.Hash}";
+  }};
+}};"""
+                nixName, NixExpression output
+            )
+            |> Map.ofSeq
+
+        {
+            Workloads = Map.ofList [workloadName, primary]
+            Packs = secondaries
+            Aliases =
+                state.Aliases
+                |> Map.map (fun _ -> Map.map (fun _ v -> v.Name))
+        }

MauiDotnetFlake/maui-dotnet-flake.fsproj

@@ -0,0 +1,23 @@
+<Project Sdk="Microsoft.NET.Sdk">
+
+  <PropertyGroup>
+    <OutputType>Exe</OutputType>
+    <TargetFramework>net6.0</TargetFramework>
+    <RootNamespace>maui_dotnet_flake</RootNamespace>
+  </PropertyGroup>
+
+  <ItemGroup>
+    <Compile Include="Domain.fs" />
+    <Compile Include="Async.fs" />
+    <Compile Include="Hash.fs" />
+    <Compile Include="Map.fs" />
+    <Compile Include="State.fs" />
+    <Compile Include="Program.fs" />
+  </ItemGroup>
+
+  <ItemGroup>
+    <PackageReference Include="FSharp.Collections.ParallelSeq" Version="1.2.0" />
+    <PackageReference Include="Newtonsoft.Json" Version="13.0.1" />
+  </ItemGroup>
+
+</Project>

README.md

@@ -0,0 +1,38 @@
+# 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`
+1. `dotnet new maui --name MauiTest && cd MauiTest`
+1. 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.
+1. `dotnet build`.
+
+## 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 if .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]`.

dotnet-workload-install-maui.txt

@@ -0,0 +1,253 @@
+Welcome to .NET 6.0!
+---------------------
+SDK Version: 6.0.301
+
+Telemetry
+---------
+The .NET tools collect usage data in order to help us improve your experience. It is collected by Microsoft and shared with the community. You can opt-out of telemetry by setting the DOTNET_CLI_TELEMETRY_OPTOUT environment variable to '1' or 'true' using your favorite shell.
+
+Read more about .NET CLI Tools telemetry: https://aka.ms/dotnet-cli-telemetry
+
+----------------
+Installed an ASP.NET Core HTTPS development certificate.
+To trust the certificate run 'dotnet dev-certs https --trust' (Windows and macOS only).
+Learn about HTTPS: https://aka.ms/dotnet-https
+----------------
+Write your first app: https://aka.ms/dotnet-hello-world
+Find out what's new: https://aka.ms/dotnet-whats-new
+Explore documentation: https://aka.ms/dotnet-docs
+Report issues and find source on GitHub: https://github.com/dotnet/core
+Use 'dotnet --help' to see available commands or visit: https://aka.ms/dotnet-cli
+--------------------------------------------------------------------------------------
+
+Skipping NuGet package signature verification.
+Skipping NuGet package signature verification.
+Skipping NuGet package signature verification.
+Installing workload manifest microsoft.net.sdk.tvos version 15.4.315…
+Installing workload manifest microsoft.net.sdk.android version 32.0.440…
+Installing workload manifest microsoft.net.sdk.maui version 6.0.419…
+Installing workload manifest microsoft.net.sdk.macos version 12.3.315…
+Installing workload manifest microsoft.net.sdk.maccatalyst version 15.4.315…
+Installing workload manifest microsoft.net.sdk.ios version 15.4.315…
+Installing workload manifest microsoft.net.workload.mono.toolchain version 6.0.7…
+Installing pack Microsoft.Maui.Core.Ref.android version 6.0.419...
+Writing workload pack installation record for Microsoft.Maui.Core.Ref.android version 6.0.419...
+Installing pack Microsoft.Maui.Core.Runtime.android version 6.0.419...
+Writing workload pack installation record for Microsoft.Maui.Core.Runtime.android version 6.0.419...
+Installing pack Microsoft.Maui.Controls.Ref.android version 6.0.419...
+Writing workload pack installation record for Microsoft.Maui.Controls.Ref.android version 6.0.419...
+Installing pack Microsoft.Maui.Controls.Runtime.android version 6.0.419...
+Writing workload pack installation record for Microsoft.Maui.Controls.Runtime.android version 6.0.419...
+Installing pack Microsoft.Maui.Essentials.Ref.android version 6.0.419...
+Writing workload pack installation record for Microsoft.Maui.Essentials.Ref.android version 6.0.419...
+Installing pack Microsoft.Maui.Essentials.Runtime.android version 6.0.419...
+Writing workload pack installation record for Microsoft.Maui.Essentials.Runtime.android version 6.0.419...
+Installing pack Microsoft.AspNetCore.Components.WebView.Maui version 6.0.419...
+Writing workload pack installation record for Microsoft.AspNetCore.Components.WebView.Maui version 6.0.419...
+Installing pack Microsoft.Maui.Dependencies version 6.0.419...
+Writing workload pack installation record for Microsoft.Maui.Dependencies version 6.0.419...
+Installing pack Microsoft.Maui.Sdk version 6.0.419...
+Writing workload pack installation record for Microsoft.Maui.Sdk version 6.0.419...
+Installing pack Microsoft.Maui.Extensions version 6.0.419...
+Writing workload pack installation record for Microsoft.Maui.Extensions version 6.0.419...
+Installing pack Microsoft.Maui.Graphics version 6.0.403...
+Writing workload pack installation record for Microsoft.Maui.Graphics version 6.0.403...
+Installing pack Microsoft.Maui.Resizetizer.Sdk version 6.0.419...
+Writing workload pack installation record for Microsoft.Maui.Resizetizer.Sdk version 6.0.419...
+Installing pack Microsoft.Maui.Templates-6.0 version 6.0.419...
+Writing workload pack installation record for Microsoft.Maui.Templates-6.0 version 6.0.419...
+Installing pack Microsoft.Maui.Core.Ref.any version 6.0.419...
+Writing workload pack installation record for Microsoft.Maui.Core.Ref.any version 6.0.419...
+Installing pack Microsoft.Maui.Core.Runtime.any version 6.0.419...
+Writing workload pack installation record for Microsoft.Maui.Core.Runtime.any version 6.0.419...
+Installing pack Microsoft.Maui.Controls.Ref.any version 6.0.419...
+Writing workload pack installation record for Microsoft.Maui.Controls.Ref.any version 6.0.419...
+Installing pack Microsoft.Maui.Controls.Runtime.any version 6.0.419...
+Writing workload pack installation record for Microsoft.Maui.Controls.Runtime.any version 6.0.419...
+Installing pack Microsoft.Maui.Essentials.Ref.any version 6.0.419...
+Writing workload pack installation record for Microsoft.Maui.Essentials.Ref.any version 6.0.419...
+Installing pack Microsoft.Maui.Essentials.Runtime.any version 6.0.419...
+Writing workload pack installation record for Microsoft.Maui.Essentials.Runtime.any version 6.0.419...
+Installing pack Microsoft.Android.Sdk version 32.0.440...
+===============Writing workload pack installation record for Microsoft.Android.Sdk version 32.0.440...
+Installing pack Microsoft.Android.Ref.31 version 32.0.440...
+Writing workload pack installation record for Microsoft.Android.Ref.31 version 32.0.440...
+Installing pack Microsoft.Android.Ref.32 version 32.0.440...
+Writing workload pack installation record for Microsoft.Android.Ref.32 version 32.0.440...
+Installing pack Microsoft.Android.Runtime.32.android-arm version 32.0.440...
+Writing workload pack installation record for Microsoft.Android.Runtime.32.android-arm version 32.0.440...
+Installing pack Microsoft.Android.Runtime.32.android-arm64 version 32.0.440...
+^BWriting workload pack installation record for Microsoft.Android.Runtime.32.android-arm64 version 32.0.440...
+Installing pack Microsoft.Android.Runtime.32.android-x86 version 32.0.440...
+^R
+Writing workload pack installation record for Microsoft.Android.Runtime.32.android-x86 version 32.0.440...
+Installing pack Microsoft.Android.Runtime.32.android-x64 version 32.0.440...
+Writing workload pack installation record for Microsoft.Android.Runtime.32.android-x64 version 32.0.440...
+Installing pack Microsoft.Android.Templates version 32.0.440...
+Writing workload pack installation record for Microsoft.Android.Templates version 32.0.440...
+Installing pack Microsoft.NETCore.App.Runtime.Mono.android-arm version 6.0.7...
+Writing workload pack installation record for Microsoft.NETCore.App.Runtime.Mono.android-arm version 6.0.7...
+Installing pack Microsoft.NETCore.App.Runtime.Mono.android-arm64 version 6.0.7...
+Writing workload pack installation record for Microsoft.NETCore.App.Runtime.Mono.android-arm64 version 6.0.7...
+Installing pack Microsoft.NETCore.App.Runtime.Mono.android-x64 version 6.0.7...
+Writing workload pack installation record for Microsoft.NETCore.App.Runtime.Mono.android-x64 version 6.0.7...
+Installing pack Microsoft.NETCore.App.Runtime.Mono.android-x86 version 6.0.7...
+Writing workload pack installation record for Microsoft.NETCore.App.Runtime.Mono.android-x86 version 6.0.7...
+Installing pack Microsoft.NET.Runtime.MonoAOTCompiler.Task version 6.0.7...
+Writing workload pack installation record for Microsoft.NET.Runtime.MonoAOTCompiler.Task version 6.0.7...
+Installing pack Microsoft.NET.Runtime.MonoTargets.Sdk version 6.0.7...
+Writing workload pack installation record for Microsoft.NET.Runtime.MonoTargets.Sdk version 6.0.7...
+Installing pack Microsoft.NETCore.App.Runtime.AOT.Cross.android-x86 version 6.0.7...
+===Writing workload pack installation record for Microsoft.NETCore.App.Runtime.AOT.Cross.android-x86 version 6.0.7...
+Installing pack Microsoft.NETCore.App.Runtime.AOT.Cross.android-x64 version 6.0.7...
+===Writing workload pack installation record for Microsoft.NETCore.App.Runtime.AOT.Cross.android-x64 version 6.0.7...
+Installing pack Microsoft.NETCore.App.Runtime.AOT.Cross.android-arm version 6.0.7...
+===Writing workload pack installation record for Microsoft.NETCore.App.Runtime.AOT.Cross.android-arm version 6.0.7...
+Installing pack Microsoft.NETCore.App.Runtime.AOT.Cross.android-arm64 version 6.0.7...
+===Writing workload pack installation record for Microsoft.NETCore.App.Runtime.AOT.Cross.android-arm64 version 6.0.7...
+Installing pack Microsoft.Maui.Core.Ref.ios version 6.0.419...
+Writing workload pack installation record for Microsoft.Maui.Core.Ref.ios version 6.0.419...
+Installing pack Microsoft.Maui.Core.Runtime.ios version 6.0.419...
+Writing workload pack installation record for Microsoft.Maui.Core.Runtime.ios version 6.0.419...
+Installing pack Microsoft.Maui.Controls.Ref.ios version 6.0.419...
+Writing workload pack installation record for Microsoft.Maui.Controls.Ref.ios version 6.0.419...
+Installing pack Microsoft.Maui.Controls.Runtime.ios version 6.0.419...
+Writing workload pack installation record for Microsoft.Maui.Controls.Runtime.ios version 6.0.419...
+Installing pack Microsoft.Maui.Essentials.Ref.ios version 6.0.419...
+Writing workload pack installation record for Microsoft.Maui.Essentials.Ref.ios version 6.0.419...
+Installing pack Microsoft.Maui.Essentials.Runtime.ios version 6.0.419...
+Writing workload pack installation record for Microsoft.Maui.Essentials.Runtime.ios version 6.0.419...
+Installing pack Microsoft.iOS.Sdk version 15.4.315...
+====Writing workload pack installation record for Microsoft.iOS.Sdk version 15.4.315...
+Installing pack Microsoft.iOS.Ref version 15.4.315...
+Writing workload pack installation record for Microsoft.iOS.Ref version 15.4.315...
+Installing pack Microsoft.iOS.Runtime.ios-arm version 15.4.315...
+Writing workload pack installation record for Microsoft.iOS.Runtime.ios-arm version 15.4.315...
+Installing pack Microsoft.iOS.Runtime.ios-arm64 version 15.4.315...
+Writing workload pack installation record for Microsoft.iOS.Runtime.ios-arm64 version 15.4.315...
+Installing pack Microsoft.iOS.Runtime.iossimulator-x86 version 15.4.315...
+Writing workload pack installation record for Microsoft.iOS.Runtime.iossimulator-x86 version 15.4.315...
+Installing pack Microsoft.iOS.Runtime.iossimulator-x64 version 15.4.315...
+Writing workload pack installation record for Microsoft.iOS.Runtime.iossimulator-x64 version 15.4.315...
+Installing pack Microsoft.iOS.Runtime.iossimulator-arm64 version 15.4.315...
+Writing workload pack installation record for Microsoft.iOS.Runtime.iossimulator-arm64 version 15.4.315...
+Installing pack Microsoft.iOS.Templates version 15.4.315...
+Writing workload pack installation record for Microsoft.iOS.Templates version 15.4.315...
+Installing pack Microsoft.NETCore.App.Runtime.AOT.Cross.ios-arm version 6.0.7...
+===Writing workload pack installation record for Microsoft.NETCore.App.Runtime.AOT.Cross.ios-arm version 6.0.7...
+Installing pack Microsoft.NETCore.App.Runtime.AOT.Cross.ios-arm64 version 6.0.7...
+===Writing workload pack installation record for Microsoft.NETCore.App.Runtime.AOT.Cross.ios-arm64 version 6.0.7...
+Installing pack Microsoft.NETCore.App.Runtime.AOT.Cross.iossimulator-arm64 version 6.0.7...
+===Writing workload pack installation record for Microsoft.NETCore.App.Runtime.AOT.Cross.iossimulator-arm64 version 6.0.7...
+Installing pack Microsoft.NETCore.App.Runtime.AOT.Cross.iossimulator-x64 version 6.0.7...
+===Writing workload pack installation record for Microsoft.NETCore.App.Runtime.AOT.Cross.iossimulator-x64 version 6.0.7...
+Installing pack Microsoft.NETCore.App.Runtime.AOT.Cross.iossimulator-x86 version 6.0.7...
+===Writing workload pack installation record for Microsoft.NETCore.App.Runtime.AOT.Cross.iossimulator-x86 version 6.0.7...
+Installing pack Microsoft.NETCore.App.Runtime.Mono.ios-arm version 6.0.7...
+Writing workload pack installation record for Microsoft.NETCore.App.Runtime.Mono.ios-arm version 6.0.7...
+Installing pack Microsoft.NETCore.App.Runtime.Mono.ios-arm64 version 6.0.7...
+Writing workload pack installation record for Microsoft.NETCore.App.Runtime.Mono.ios-arm64 version 6.0.7...
+Installing pack Microsoft.NETCore.App.Runtime.Mono.iossimulator-arm64 version 6.0.7...
+Writing workload pack installation record for Microsoft.NETCore.App.Runtime.Mono.iossimulator-arm64 version 6.0.7...
+Installing pack Microsoft.NETCore.App.Runtime.Mono.iossimulator-x64 version 6.0.7...
+Writing workload pack installation record for Microsoft.NETCore.App.Runtime.Mono.iossimulator-x64 version 6.0.7...
+Installing pack Microsoft.NETCore.App.Runtime.Mono.iossimulator-x86 version 6.0.7...
+Writing workload pack installation record for Microsoft.NETCore.App.Runtime.Mono.iossimulator-x86 version 6.0.7...
+Installing pack Microsoft.Maui.Core.Ref.tizen version 6.0.419...
+Writing workload pack installation record for Microsoft.Maui.Core.Ref.tizen version 6.0.419...
+Installing pack Microsoft.Maui.Core.Runtime.tizen version 6.0.419...
+Writing workload pack installation record for Microsoft.Maui.Core.Runtime.tizen version 6.0.419...
+Installing pack Microsoft.Maui.Controls.Ref.tizen version 6.0.419...
+Writing workload pack installation record for Microsoft.Maui.Controls.Ref.tizen version 6.0.419...
+Installing pack Microsoft.Maui.Controls.Runtime.tizen version 6.0.419...
+Writing workload pack installation record for Microsoft.Maui.Controls.Runtime.tizen version 6.0.419...
+Installing pack Microsoft.Maui.Essentials.Ref.tizen version 6.0.419...
+Writing workload pack installation record for Microsoft.Maui.Essentials.Ref.tizen version 6.0.419...
+Installing pack Microsoft.Maui.Essentials.Runtime.tizen version 6.0.419...
+Writing workload pack installation record for Microsoft.Maui.Essentials.Runtime.tizen version 6.0.419...
+Installing pack Microsoft.Maui.Core.Ref.maccatalyst version 6.0.419...
+Writing workload pack installation record for Microsoft.Maui.Core.Ref.maccatalyst version 6.0.419...
+Installing pack Microsoft.Maui.Core.Runtime.maccatalyst version 6.0.419...
+Writing workload pack installation record for Microsoft.Maui.Core.Runtime.maccatalyst version 6.0.419...
+Installing pack Microsoft.Maui.Controls.Ref.maccatalyst version 6.0.419...
+Writing workload pack installation record for Microsoft.Maui.Controls.Ref.maccatalyst version 6.0.419...
+Installing pack Microsoft.Maui.Controls.Runtime.maccatalyst version 6.0.419...
+Writing workload pack installation record for Microsoft.Maui.Controls.Runtime.maccatalyst version 6.0.419...
+Installing pack Microsoft.Maui.Essentials.Ref.maccatalyst version 6.0.419...
+Writing workload pack installation record for Microsoft.Maui.Essentials.Ref.maccatalyst version 6.0.419...
+Installing pack Microsoft.Maui.Essentials.Runtime.maccatalyst version 6.0.419...
+Writing workload pack installation record for Microsoft.Maui.Essentials.Runtime.maccatalyst version 6.0.419...
+Installing pack Microsoft.MacCatalyst.Sdk version 15.4.315...
+==Writing workload pack installation record for Microsoft.MacCatalyst.Sdk version 15.4.315...
+Installing pack Microsoft.MacCatalyst.Ref version 15.4.315...
+Writing workload pack installation record for Microsoft.MacCatalyst.Ref version 15.4.315...
+Installing pack Microsoft.MacCatalyst.Runtime.maccatalyst-arm64 version 15.4.315...
+Writing workload pack installation record for Microsoft.MacCatalyst.Runtime.maccatalyst-arm64 version 15.4.315...
+Installing pack Microsoft.MacCatalyst.Runtime.maccatalyst-x64 version 15.4.315...
+Writing workload pack installation record for Microsoft.MacCatalyst.Runtime.maccatalyst-x64 version 15.4.315...
+Installing pack Microsoft.MacCatalyst.Templates version 15.4.315...
+Writing workload pack installation record for Microsoft.MacCatalyst.Templates version 15.4.315...
+Installing pack Microsoft.NETCore.App.Runtime.AOT.Cross.maccatalyst-arm64 version 6.0.7...
+===Writing workload pack installation record for Microsoft.NETCore.App.Runtime.AOT.Cross.maccatalyst-arm64 version 6.0.7...
+Installing pack Microsoft.NETCore.App.Runtime.AOT.Cross.maccatalyst-x64 version 6.0.7...
+===Writing workload pack installation record for Microsoft.NETCore.App.Runtime.AOT.Cross.maccatalyst-x64 version 6.0.7...
+Installing pack Microsoft.NETCore.App.Runtime.Mono.maccatalyst-arm64 version 6.0.7...
+Writing workload pack installation record for Microsoft.NETCore.App.Runtime.Mono.maccatalyst-arm64 version 6.0.7...
+Installing pack Microsoft.NETCore.App.Runtime.Mono.maccatalyst-x64 version 6.0.7...
+Writing workload pack installation record for Microsoft.NETCore.App.Runtime.Mono.maccatalyst-x64 version 6.0.7...
+Installing pack Microsoft.Maui.Core.Ref.win version 6.0.419...
+Writing workload pack installation record for Microsoft.Maui.Core.Ref.win version 6.0.419...
+Installing pack Microsoft.Maui.Core.Runtime.win version 6.0.419...
+Writing workload pack installation record for Microsoft.Maui.Core.Runtime.win version 6.0.419...
+Installing pack Microsoft.Maui.Controls.Ref.win version 6.0.419...
+Writing workload pack installation record for Microsoft.Maui.Controls.Ref.win version 6.0.419...
+Installing pack Microsoft.Maui.Controls.Runtime.win version 6.0.419...
+Writing workload pack installation record for Microsoft.Maui.Controls.Runtime.win version 6.0.419...
+Installing pack Microsoft.Maui.Essentials.Ref.win version 6.0.419...
+Writing workload pack installation record for Microsoft.Maui.Essentials.Ref.win version 6.0.419...
+Installing pack Microsoft.Maui.Essentials.Runtime.win version 6.0.419...
+Writing workload pack installation record for Microsoft.Maui.Essentials.Runtime.win version 6.0.419...
+Installing pack Microsoft.Maui.Graphics.Win2D.WinUI.Desktop version 6.0.403...
+Writing workload pack installation record for Microsoft.Maui.Graphics.Win2D.WinUI.Desktop version 6.0.403...
+Garbage collecting for SDK feature band(s) 6.0.300...
+
+Successfully installed workload(s) maui.
+
+installPhase completed in 4 minutes 52 seconds
+post-installation fixup
+rewriting symlink /nix/store/8b43vbzjrmpdb5qw7may8czy74q53mfw-dotnet-sdk-6.0.301/bin/dotnet to be relative to /nix/store/8b43vbzjrmpdb5qw7may8czy74q53mfw-dotnet-sdk-6.0.301
+strip is /nix/store/90madzhlr2rnzx2zihn3295ysr0jx325-clang-wrapper-11.1.0/bin/strip
+stripping (with command strip and flags -S) in /nix/store/8b43vbzjrmpdb5qw7may8czy74q53mfw-dotnet-sdk-6.0.301/bin
+patching script interpreter paths in /nix/store/8b43vbzjrmpdb5qw7may8czy74q53mfw-dotnet-sdk-6.0.301
+/nix/store/8b43vbzjrmpdb5qw7may8czy74q53mfw-dotnet-sdk-6.0.301/packs/Microsoft.MacCatalyst.Sdk/15.4.315/tools/bin/bgen: interpreter directive changed from "#!/bin/bash -e" to "/nix/store/m6pqblbr77ady86apyl7ickafgprjd9f-bash-5.1-p16/bin/bash -e"
+/nix/store/8b43vbzjrmpdb5qw7may8czy74q53mfw-dotnet-sdk-6.0.301/packs/Microsoft.Android.Sdk.Darwin/32.0.440/tools/Darwin/jit-times: interpreter directive changed from "#!/bin/sh" to "/nix/store/m6pqblbr77ady86apyl7ickafgprjd9f-bash-5.1-p16/bin/sh"
+/nix/store/8b43vbzjrmpdb5qw7may8czy74q53mfw-dotnet-sdk-6.0.301/packs/Microsoft.Android.Sdk.Darwin/32.0.440/tools/Darwin/illinkanalyzer: interpreter directive changed from "#!/bin/sh" to "/nix/store/m6pqblbr77ady86apyl7ickafgprjd9f-bash-5.1-p16/bin/sh"
+/nix/store/8b43vbzjrmpdb5qw7may8czy74q53mfw-dotnet-sdk-6.0.301/packs/Microsoft.iOS.Sdk/15.4.315/tools/bin/mlaunch: interpreter directive changed from "#!/bin/bash -e" to "/nix/store/m6pqblbr77ady86apyl7ickafgprjd9f-bash-5.1-p16/bin/bash -e"
+/nix/store/8b43vbzjrmpdb5qw7may8czy74q53mfw-dotnet-sdk-6.0.301/packs/Microsoft.iOS.Sdk/15.4.315/tools/bin/bgen: interpreter directive changed from "#!/bin/bash -e" to "/nix/store/m6pqblbr77ady86apyl7ickafgprjd9f-bash-5.1-p16/bin/bash -e"
+running install tests
+=.NET SDK (reflecting any global.json):
+ Version:   6.0.301
+ Commit:    43f9b18481
+
+Runtime Environment:
+ OS Name:     Mac OS X
+ OS Version:  12.4
+ OS Platform: Darwin
+ RID:         osx.12-arm64
+ Base Path:   /nix/store/8b43vbzjrmpdb5qw7may8czy74q53mfw-dotnet-sdk-6.0.301/sdk/6.0.301/
+
+Host (useful for support):
+  Version: 6.0.6
+  Commit:  7cca709db2
+
+.NET SDKs installed:
+  6.0.301 [/nix/store/8b43vbzjrmpdb5qw7may8czy74q53mfw-dotnet-sdk-6.0.301/sdk]
+
+.NET runtimes installed:
+  Microsoft.AspNetCore.App 6.0.6 [/nix/store/8b43vbzjrmpdb5qw7may8czy74q53mfw-dotnet-sdk-6.0.301/shared/Microsoft.AspNetCore.App]
+  Microsoft.NETCore.App 6.0.6 [/nix/store/8b43vbzjrmpdb5qw7may8czy74q53mfw-dotnet-sdk-6.0.301/shared/Microsoft.NETCore.App]
+
+To install additional .NET runtimes or SDKs:
+  https://aka.ms/dotnet-download
+warning: dumping very large path (> 256 MiB); this may run out of memory
+/nix/store/4qhpk4hixrmdg7rrkblppbm8s4alj6xl-dotnet-sdk-6.0.301

flake.lock

@@ -0,0 +1,79 @@
+{
+  "nodes": {
+    "flake-utils": {
+      "locked": {
+        "lastModified": 1638122382,
+        "narHash": "sha256-sQzZzAbvKEqN9s0bzWuYmRaA03v40gaJ4+iL1LXjaeI=",
+        "owner": "numtide",
+        "repo": "flake-utils",
+        "rev": "74f7e4319258e287b0f9cb95426c9853b282730b",
+        "type": "github"
+      },
+      "original": {
+        "owner": "numtide",
+        "repo": "flake-utils",
+        "type": "github"
+      }
+    },
+    "nixpkgs": {
+      "locked": {
+        "lastModified": 1658777571,
+        "narHash": "sha256-gJMDUeaRhi47NxtrfFMIejlV5N3Ra2669w16Ndz2Jo0=",
+        "owner": "nixos",
+        "repo": "nixpkgs",
+        "rev": "f0fa012b649a47e408291e96a15672a4fe925d65",
+        "type": "github"
+      },
+      "original": {
+        "owner": "nixos",
+        "ref": "nixos-22.05",
+        "repo": "nixpkgs",
+        "type": "github"
+      }
+    },
+    "nixpkgs-21_11": {
+      "locked": {
+        "lastModified": 1658346836,
+        "narHash": "sha256-c9BZZbi0tqCQ4j6CMVDlsut3Q3ET1Fezf+qIslCfkhs=",
+        "owner": "nixos",
+        "repo": "nixpkgs",
+        "rev": "a1fe662eb26ffc2a036b37c4670392ade632c413",
+        "type": "github"
+      },
+      "original": {
+        "owner": "nixos",
+        "ref": "nixos-21.11",
+        "repo": "nixpkgs",
+        "type": "github"
+      }
+    },
+    "root": {
+      "inputs": {
+        "nixpkgs": "nixpkgs",
+        "nixpkgs-21_11": "nixpkgs-21_11",
+        "utils": "utils"
+      }
+    },
+    "utils": {
+      "inputs": {
+        "flake-utils": "flake-utils"
+      },
+      "locked": {
+        "lastModified": 1638172912,
+        "narHash": "sha256-jxhQGNEsZTdop/Br3JPS+xmBf6t9cIWRzVZFxbT76Rw=",
+        "owner": "gytis-ivaskevicius",
+        "repo": "flake-utils-plus",
+        "rev": "166d6ebd9f0de03afc98060ac92cba9c71cfe550",
+        "type": "github"
+      },
+      "original": {
+        "owner": "gytis-ivaskevicius",
+        "ref": "v1.3.1",
+        "repo": "flake-utils-plus",
+        "type": "github"
+      }
+    }
+  },
+  "root": "root",
+  "version": 7
+}

flake.nix

@@ -0,0 +1,265 @@
+{
+  inputs = {
+    nixpkgs.url = "github:nixos/nixpkgs/nixos-22.05";
+    nixpkgs-21_11.url = "github:nixos/nixpkgs/nixos-21.11";
+    utils.url = "github:gytis-ivaskevicius/flake-utils-plus/v1.3.1";
+  };
+
+  outputs = inputs @ {
+    self,
+    nixpkgs,
+    utils,
+    ...
+  }:
+    utils.lib.mkFlake {
+      inherit self inputs;
+      # for Android:
+      # channelsConfig.android_sdk.accept_license = true;
+      outputsBuilder = channels: let
+        inherit (channels.nixpkgs) lib buildEnv dotnetCorePackages stdenvNoCC;
+        platform =
+          (
+            if stdenvNoCC.isLinux
+            then "linux"
+            else if stdenvNoCC.isDarwin
+            then "osx"
+            else abort "unknown platform"
+          )
+          + "-"
+          + (
+            if stdenvNoCC.hostPlatform.parsed.cpu.family == "x86"
+            then "x"
+            else stdenvNoCC.hostPlatform.parsed.cpu.family
+          )
+          + builtins.toString stdenvNoCC.hostPlatform.parsed.cpu.bits;
+
+        withWorkload = dotnet: workloads:
+          channels.nixpkgs.callPackage (import ./combine-packages.nix dotnet workloads) {};
+
+        fetchNuGet = {
+          pname,
+          version,
+          hash,
+        }:
+          channels.nixpkgs.fetchurl {
+            name = "nuget-${pname}-${version}.nupkg";
+            url = "https://www.nuget.org/api/v2/package/${pname}/${version}";
+            inherit hash;
+          };
+
+        buildDotnetWorkload = input: let
+          name = "f${input.pname}-${input.version}";
+          workloadName = input.workloadName or null;
+          sdkVersion = dotnetCorePackages.sdk_6_0.version;
+          workload = channels.nixpkgs.stdenvNoCC.mkDerivation {
+            inherit (input) pname version src;
+
+            sourceRoot = "${name}";
+
+            nativeBuildInputs = [channels.nixpkgs.unzip];
+
+            preUnpack = ''mkdir "$sourceRoot"'';
+            unpackCmd = ''unzip -qq $curSrc -d "$sourceRoot"'';
+
+            dontConfigure = true;
+            dontBuild = true;
+
+            installPhase =
+              ''
+                workload_out="$out/sdk-manifests/${sdkVersion}/${lib.toLower input.pname}"
+                mkdir -p "$workload_out"
+                chmod -R ugo+r data # Work around some nupkgs having no permissions set
+                cp -R data/* "$workload_out"
+              ''
+              + lib.optionalString (!builtins.isNull workloadName) ''
+                installed_workloads_out="$out/metadata/workloads/${sdkVersion}/InstalledWorkloads"
+                mkdir -p "$installed_workloads_out"
+                touch "$installed_workloads_out/${workloadName}"
+              '';
+          };
+        in
+          buildEnv {
+            name = "workload-${name}-combined";
+            paths = nixpkgs.lib.lists.filter (x: !(builtins.isNull x)) (nixpkgs.lib.lists.map (pack:
+              if nixpkgs.lib.hasAttr "pname" pack
+              then pack
+              else nixpkgs.lib.attrsets.attrByPath [platform] null pack) (input.workloadPacks or [])
+            ++ [workload]);
+            pathsToLink = ["/metadata" "/library-packs" "/packs" "/template-packs" "/sdk-manifests" "/tool-packs"];
+          };
+
+        allManifests = import ./workload-manifest-list.nix fetchNuGet;
+
+        composeDotnetWorkload = workloads: let
+          builtWorkloads =
+            nixpkgs.lib.lists.map buildDotnetWorkload workloads;
+          name = nixpkgs.lib.concatStrings builtWorkloads;
+          fallbackWorkloads =
+            builtins.filter (fallback: nixpkgs.lib.lists.all (desired: desired.src != fallback.src) workloads) allManifests;
+        in
+          buildEnv {
+            name = "workload-${name}-combined";
+            paths =
+              builtWorkloads ++ nixpkgs.lib.lists.map buildDotnetWorkload fallbackWorkloads;
+          };
+
+        buildDotnetPack = {
+          name ? "${pname}-${version}",
+          pname,
+          version,
+          src,
+          kind,
+          dotnet_sdk ? dotnetCorePackages.sdk_6_0,
+        }: let
+          kindMapping = {
+            "framework" = 1;
+            "sdk" = 0;
+            "template" = 3;
+            "library" = 2;
+          };
+          manifest = {
+            Id = pname;
+            Version = version;
+            Kind = kindMapping."${kind}";
+            ResolvedPackageId = pname;
+            Path =
+              builtins.placeholder "out"
+              + (
+                if kind == "template"
+                then "/template-packs/${pname}/${version}/${pname}.nupkg"
+                else if kind == "library"
+                then "/library-packs/${pname}.${version}.nupkg"
+                else "/packs/${pname}/${version}"
+              );
+            IsStillPacked = kind != "template";
+          };
+        in
+          channels.nixpkgs.stdenvNoCC.mkDerivation {
+            inherit pname version src;
+
+            sourceRoot = "${pname}-${version}";
+
+            nativeBuildInputs = [channels.nixpkgs.unzip channels.nixpkgs-21_11.yq];
+
+            preUnpack = ''mkdir "$sourceRoot"'';
+            unpackCmd = ''unzip -qq $curSrc -d "$sourceRoot"'';
+
+            dontConfigure = true;
+            dontBuild = true;
+
+            meta.priority = -1;
+            installPhase =
+              lib.optionalString (kind != "template") ''
+                workload_out="$out/packs/${pname}/${version}"
+                mkdir -p "$workload_out"
+                # Install workload files
+                for f in $(ls -1 | grep -vE '\[Content_Types\].xml|_rels|package'); do
+                  # Some package contents have no read access?!
+                  chmod a+r -R "$f"
+                  ls -la "$f"
+                  cp -R "$f" "$workload_out"
+                done
+                # Set file permissions (e.g., for shell scripts)
+                if [ -f data/UnixFilePermissions.xml ]; then
+                  declare -A perms="($(xq -r '.FileList.File | .[] | @sh "[\(."@Path")]=\(."@Permission")"' data/UnixFilePermissions.xml))"
+                  for file in "''${!perms[@]}"; do
+                    chmod "''${perms[$file]}" "$workload_out/$file"
+                  done
+                fi
+              ''
+              + ''
+                nupkg_out="$out/${
+                  if kind == "template"
+                  then "template-packs"
+                  else "packs/${pname}/${version}"
+                }"
+                nupkg_name="${
+                  if kind == "template"
+                  then (lib.toLower "${pname}.${version}")
+                  else pname
+                }"
+                mkdir -p "$nupkg_out"
+                cp "$src" "$nupkg_out/$nupkg_name.nupkg"
+                # Register metadata
+                metadata_out="$out/metadata/workloads/InstalledPacks/v1/${pname}/${version}"
+                mkdir -p "$metadata_out"
+                echo '${builtins.toJSON manifest}' > "$metadata_out/${dotnet_sdk.version}"
+                # Copy signature
+                ${
+                  if kind != "template"
+                  then ''cp .signature.p7s "$nupkg_out"''
+                  else ""
+                }
+              '';
+          };
+      in {
+        devShell = let
+          inherit (channels.nixpkgs) lib mkShell stdenv dotnetCorePackages jdk11 androidenv;
+
+          manifest = import ./workload-manifest-contents.nix {inherit buildDotnetPack buildDotnetWorkload fetchNuGet;};
+          workload = composeDotnetWorkload [manifest.maui manifest.microsoft-net-runtime-android manifest.ios manifest.maccatalyst];
+
+          dotnet_sdk = dotnetCorePackages.sdk_6_0.overrideAttrs (old: let
+            major = lib.versions.major old.version;
+            minor = lib.versions.minor old.version;
+            patch = lib.versions.patch old.version;
+            featureBand = "${major}.${minor}.${builtins.substring 0 1 patch}00";
+            rpath = with channels.nixpkgs;
+              lib.makeLibraryPath [
+                stdenv.cc.cc
+                zlib
+                curl
+                icu
+                libunwind
+                libuuid
+                openssl
+              ];
+          in {
+            nativeBuildInputs = old.nativeBuildInputs or [] ++ [channels.nixpkgs.makeBinaryWrapper];
+            postFixup =
+              old.postFixup
+              + ''
+                rm "$out/bin/dotnet"
+                rm -r "$out/sdk-manifests"
+                cp -r "${workload}/metadata" "$out/metadata"
+                cp -r "${workload}/template-packs" "$out/template-packs"
+                cp -r "${workload}/tool-packs" "$out/tool-packs"
+                makeBinaryWrapper "$out/dotnet" "$out/bin/dotnet" \
+                  --set DOTNETSDK_WORKLOAD_PACK_ROOTS "${workload}" \
+                  --set DOTNETSDK_WORKLOAD_MANIFEST_ROOTS "${workload}/sdk-manifests" \
+                  --set DYLD_FALLBACK_LIBRARY_PATH "${rpath}" \
+                  --set DOTNET_CLI_WORKLOAD_UPDATE_NOTIFY_DISABLE "true"
+              '';
+            sandboxProfile = ''(allow file-read* (literal "/usr/share/icu/icudt70l.dat"))'';
+          });
+          # for Android:
+          # android = androidenv.composeAndroidPackages {
+          #               toolsVersion = "26.1.1";
+          #               platformToolsVersion = "30.0.5";
+          #               buildToolsVersions = [ "30.0.3" ];
+          #               includeEmulator = false;
+          #               emulatorVersion = "30.3.4";
+          #               platformVersions = [ "28" "29" "30" ];
+          #               includeSources = false;
+          #               includeSystemImages = false;
+          #               systemImageTypes = [ "google_apis_playstore" ];
+          #               abiVersions = [ "armeabi-v7a" "arm64-v8a" ];
+          #               cmakeVersions = [ "3.10.2" ];
+          #               includeNDK = true;
+          #               ndkVersions = ["22.0.7026061"];
+          #               useGoogleAPIs = false;
+          #               useGoogleTVAddOns = false;
+          #               includeExtras = [
+          #                 "extras;google;gcm"
+          #               ];
+          #             };
+          # then use jdk11 and android.androidsdk in the packages
+        in
+          mkShell {
+            packages = [dotnet_sdk];
+            DOTNET_ROOT = "${dotnet_sdk}";
+            DOTNET_CLI_TELEMETRY_OPTOUT = "1";
+          };
+      };
+    };
+}

workload-manifest-list.nix

@@ -0,0 +1,82 @@
+fetchNuGet: [
+{
+  pname = "microsoft.net.sdk.android";
+  version = "32.0.440";
+  src = fetchNuGet {
+    version = "32.0.440";
+    hash = "sha256-IBcXur/I4Su+2PiVLuheS0sIxOAHSsS9XMW2knhYCE8=";
+    pname = "microsoft.net.sdk.android.manifest-6.0.300";
+  };
+  workloadPacks = [];
+}
+{
+  pname = "microsoft.net.sdk.ios";
+  version = "15.4.328";
+  src = fetchNuGet {
+    version = "15.4.328";
+    hash = "sha256-BMtCkuBydIlnH5yohg6yKc6lqQ4jcvz9rpP7jLtO5G0=";
+    pname = "microsoft.net.sdk.ios.manifest-6.0.300";
+  };
+  workloadPacks = [];
+}
+{
+  pname = "microsoft.net.sdk.maccatalyst";
+  version = "15.4.328";
+  src = fetchNuGet {
+    version = "15.4.328";
+    hash = "sha256-2G3fLcQKNq2v2aTN13ZNMWdhAfJ5Iv3m6dFzl4c0WqY=";
+    pname = "microsoft.net.sdk.maccatalyst.manifest-6.0.300";
+  };
+  workloadPacks = [];
+}
+{
+  pname = "microsoft.net.sdk.macos";
+  version = "12.3.328";
+  src = fetchNuGet {
+    version = "12.3.328";
+    hash = "sha256-5x4/JHFLKx8x2MniFEsM07GB5sR5nHj834YdYC2Wogc=";
+    pname = "microsoft.net.sdk.macos.manifest-6.0.300";
+  };
+  workloadPacks = [];
+}
+{
+  pname = "microsoft.net.sdk.maui";
+  version = "6.0.419";
+  src = fetchNuGet {
+    version = "6.0.419";
+    hash = "sha256-x84cTUrys135LGizbGMlbe9lA0/MS7bmZ5Agz4T9ooU=";
+    pname = "microsoft.net.sdk.maui.manifest-6.0.300";
+  };
+  workloadPacks = [];
+}
+{
+  pname = "microsoft.net.workload.mono.toolchain";
+  version = "6.0.7";
+  src = fetchNuGet {
+    version = "6.0.7";
+    hash = "sha256-m2W3IZkG04wqVTcq2rauXO3e8hWYh7eHaPc1T99kBjY=";
+    pname = "microsoft.net.workload.mono.toolchain.manifest-6.0.300";
+  };
+  workloadPacks = [];
+}
+{
+  pname = "microsoft.net.workload.emscripten";
+  version = "6.0.4";
+  src = fetchNuGet {
+    version = "6.0.4";
+    hash = "sha256-g5Qsrj3jt8QMysohYFlxy7O9tsN7PYilF8jxonpeORI=";
+    pname = "microsoft.net.workload.emscripten.manifest-6.0.300";
+  };
+  workloadPacks = [];
+}
+{
+  pname = "microsoft.net.sdk.tvos";
+  version = "15.4.328";
+  src = fetchNuGet {
+    version = "15.4.328";
+    hash = "sha256-I9RXJVtLboTdGrrHfcKVPgyUh+4TcarjhCmay0S8/I8=";
+    pname = "microsoft.net.sdk.tvos.manifest-6.0.300";
+  };
+  workloadPacks = [];
+}
+]