Obtain a compatible runtime from runconfig (#35)

.gitignore

@@ -10,3 +10,4 @@ result
 .analyzerpackages/
 analysis.sarif
 .direnv/
+Generated*.fs

TestRunner/Program.fs

@@ -1,8 +1,10 @@
 namespace TestRunner
 
 open System
+open WoofWare.DotnetRuntimeLocator
 open System.IO
 open System.Reflection
+open System.Runtime.Loader
 
 // Fix for https://github.com/Smaug123/unofficial-nunit-runner/issues/8
 // Set AppContext.BaseDirectory to where the test DLL is.
@@ -15,7 +17,91 @@ type SetBaseDir (testDll : FileInfo) =
         member _.Dispose () =
             AppContext.SetData ("APP_CONTEXT_BASE_DIRECTORY", oldBaseDir)
 
+
+type Ctx (dll : FileInfo, runtimes : DirectoryInfo list) =
+    inherit AssemblyLoadContext ()
+
+    override this.Load (target : AssemblyName) : Assembly =
+        let path = Path.Combine (dll.Directory.FullName, $"%s{target.Name}.dll")
+
+        if File.Exists path then
+            this.LoadFromAssemblyPath path
+        else
+
+        runtimes
+        |> List.tryPick (fun di ->
+            let path = Path.Combine (di.FullName, $"%s{target.Name}.dll")
+
+            if File.Exists path then
+                this.LoadFromAssemblyPath path |> Some
+            else
+                None
+        )
+        |> Option.defaultValue null
+
+
 module Program =
+    let selectRuntime
+        (config : RuntimeOptions)
+        (f : DotnetEnvironmentInfo)
+        : Choice<DotnetEnvironmentFrameworkInfo, DotnetEnvironmentSdkInfo> option
+        =
+        let rollForward =
+            match Environment.GetEnvironmentVariable "DOTNET_ROLL_FORWARD" with
+            | null ->
+                config.RollForward
+                |> Option.map RollForward.Parse
+                |> Option.defaultValue RollForward.Minor
+            | s -> RollForward.Parse s
+
+        let desired = Version config.Framework.Version
+
+        match rollForward with
+        | RollForward.Minor ->
+            let available =
+                f.Frameworks
+                |> Seq.choose (fun fi ->
+                    if fi.Name = config.Framework.Name then
+                        Some (fi, Version fi.Version)
+                    else
+                        None
+                )
+                |> Seq.filter (fun (_, version) -> version.Major = desired.Major && version.Minor >= desired.Minor)
+                |> Seq.tryMinBy (fun (_, version) -> version.Minor, version.Build)
+
+            match available with
+            | Some (f, _) -> Some (Choice1Of2 f)
+            | None ->
+                // TODO: maybe we can ask the SDK. But we keep on trucking: maybe we're self-contained,
+                // and we'll actually find all the runtime next to the DLL.
+                None
+        | _ -> failwith "non-minor RollForward not supported yet; please shout if you want it"
+
+    let locateRuntimes (dll : FileInfo) : DirectoryInfo list =
+        let runtimeConfig =
+            let name =
+                if not (dll.Name.EndsWith (".dll", StringComparison.OrdinalIgnoreCase)) then
+                    failwith $"Expected DLL %s{dll.FullName} to end in .dll"
+
+                dll.Name.Substring (0, dll.Name.Length - 4)
+
+            Path.Combine (dll.Directory.FullName, $"%s{name}.runtimeconfig.json")
+            |> File.ReadAllText
+            |> System.Text.Json.Nodes.JsonNode.Parse
+            |> RuntimeConfig.jsonParse
+            |> fun f -> f.RuntimeOptions
+
+        let availableRuntimes = DotnetEnvironmentInfo.Get ()
+
+        let runtime = selectRuntime runtimeConfig availableRuntimes
+
+        match runtime with
+        | None ->
+            // Keep on trucking: let's be optimistic and hope that we're self-contained.
+            [ dll.Directory ]
+        | Some (Choice1Of2 runtime) -> [ dll.Directory ; DirectoryInfo runtime.Path ]
+        | Some (Choice2Of2 sdk) -> [ dll.Directory ; DirectoryInfo sdk.Path ]
+
     let main argv =
         let testDll, filter =
             match argv |> List.ofSeq with
@@ -32,7 +118,8 @@ module Program =
 
         use _ = new SetBaseDir (testDll)
 
-        let assy = Assembly.LoadFrom testDll.FullName
+        let ctx = Ctx (testDll, locateRuntimes testDll)
+        let assy = ctx.LoadFromAssemblyPath testDll.FullName
 
         let anyFailures =
             assy.ExportedTypes

TestRunner/RuntimeConfig.fs

@@ -0,0 +1,50 @@
+namespace TestRunner
+
+open System
+open WoofWare.Myriad.Plugins
+
+[<JsonParse>]
+type FrameworkDescription =
+    {
+        Name : string
+        Version : string
+    }
+
+[<JsonParse>]
+type RuntimeOptions =
+    {
+        Tfm : string
+        Framework : FrameworkDescription
+        RollForward : string option
+    }
+
+[<JsonParse>]
+type RuntimeConfig =
+    {
+        RuntimeOptions : RuntimeOptions
+    }
+
+[<RequireQualifiedAccess>]
+type RollForward =
+    | Minor
+    | Major
+    | LatestPatch
+    | LatestMinor
+    | LatestMajor
+    | Disable
+
+    static member Parse (s : string) : RollForward =
+        if s.Equals ("minor", StringComparison.OrdinalIgnoreCase) then
+            RollForward.Minor
+        elif s.Equals ("major", StringComparison.OrdinalIgnoreCase) then
+            RollForward.Major
+        elif s.Equals ("latestpatch", StringComparison.OrdinalIgnoreCase) then
+            RollForward.LatestPatch
+        elif s.Equals ("latestminor", StringComparison.OrdinalIgnoreCase) then
+            RollForward.LatestMinor
+        elif s.Equals ("latestmajor", StringComparison.OrdinalIgnoreCase) then
+            RollForward.LatestMajor
+        elif s.Equals ("disable", StringComparison.OrdinalIgnoreCase) then
+            RollForward.Disable
+        else
+            failwith $"Could not interpret '%s{s}' as a RollForward"

TestRunner/Seq.fs

@@ -0,0 +1,22 @@
+namespace TestRunner
+
+[<RequireQualifiedAccess>]
+module internal Seq =
+
+    let tryMinBy (f : 'a -> 'b) (s : 'a seq) : 'a option =
+        use enum = s.GetEnumerator ()
+
+        if not (enum.MoveNext ()) then
+            None
+        else
+
+        let mutable answer = enum.Current
+        let mutable fAnswer = f enum.Current
+
+        while enum.MoveNext () do
+            let fNext = f enum.Current
+
+            if fNext < fAnswer then
+                answer <- enum.Current
+
+        Some answer

TestRunner/TestRunner.fsproj

@@ -15,9 +15,15 @@
     <PackageTags>nunit;test;runner</PackageTags>
     <TreatWarningsAsErrors>true</TreatWarningsAsErrors>
     <WarnOn>FS3559</WarnOn>
+    <WoofWareMyriadPluginVersion>2.1.40</WoofWareMyriadPluginVersion>
   </PropertyGroup>
 
   <ItemGroup>
+    <Compile Include="RuntimeConfig.fs" />
+    <Compile Include="GeneratedRuntimeConfig.fs">
+      <MyriadFile>RuntimeConfig.fs</MyriadFile>
+    </Compile>
+    <Compile Include="Seq.fs" />
     <Compile Include="Progress.fs" />
     <Compile Include="Program.fs" />
     <None Include="..\README.md">
@@ -32,6 +38,13 @@
 
   <ItemGroup>
     <PackageReference Include="Spectre.Console" Version="0.49.1" />
+    <PackageReference Include="WoofWare.DotnetRuntimeLocator" Version="0.1.2" />
+    <PackageReference Include="WoofWare.Myriad.Plugins.Attributes" Version="3.1.4" />
+    <PackageReference Include="Myriad.SDK" Version="0.8.3" />
+    <PackageReference Include="WoofWare.Myriad.Plugins" Version="$(WoofWareMyriadPluginVersion)" PrivateAssets="all" />
   </ItemGroup>
 
+  <ItemGroup>
+    <MyriadSdkGenerator Include="$(NuGetPackageRoot)/woofware.myriad.plugins/$(WoofWareMyriadPluginVersion)/lib/net6.0/WoofWare.Myriad.Plugins.dll" />
+  </ItemGroup>
 </Project>

nix/deps.nix

@@ -61,6 +61,11 @@
     version = "17.10.0";
     sha256 = "1bl471s7fx9jycr0cc8rylwf34mrvlg9qn1an6l86nisavfcyb7v";
   })
+  (fetchNuGet {
+    pname = "Myriad.Sdk";
+    version = "0.8.3";
+    sha256 = "0qv78c5s5m04xb8h17nnn2ig26zcyya91k2dpj745cm1cbnzvvgc";
+  })
   (fetchNuGet {
     pname = "Nerdbank.GitVersioning";
     version = "3.6.139";
@@ -176,6 +181,21 @@
     version = "7.0.3";
     sha256 = "0zjrnc9lshagm6kdb9bdh45dmlnkpwcpyssa896sda93ngbmj8k9";
   })
+  (fetchNuGet {
+    pname = "WoofWare.DotnetRuntimeLocator";
+    version = "0.1.2";
+    sha256 = "0kwkq28ddzc0bpr22jmgcl8dhnhg776gf6l054rsxw8lrvpwhmv9";
+  })
+  (fetchNuGet {
+    pname = "WoofWare.Myriad.Plugins";
+    version = "2.1.40";
+    sha256 = "025lv42zjvqpr2di0iaqhqpricqary3l2a3cxgjjl0zxzflfbmx2";
+  })
+  (fetchNuGet {
+    pname = "WoofWare.Myriad.Plugins.Attributes";
+    version = "3.1.4";
+    sha256 = "06yw013f2qs2r8bxvja2c5kzbqc5knd3sc3pf6w5gaz4fbzwc2c3";
+  })
   (fetchNuGet {
     pname = "WoofWare.PrattParser";
     version = "0.1.2";