AssembyContexts are no fun

.github/workflows/build.yml

@@ -4,6 +4,7 @@ on:
   push:
     branches:
       - main
+      - feature/assembly-context
     tags:
       - v*
   pull_request:

src/TokenMagician/ModuleAssemblyLoadContext.cs

@@ -0,0 +1,33 @@
+namespace TokenMagician;
+using System.Reflection;
+using System.Runtime.Loader;
+
+internal class ModuleAssemblyLoadContext : AssemblyLoadContext
+    {
+        private readonly string _dependencyDirPath;
+
+        public ModuleAssemblyLoadContext(string dependencyDirPath)
+        {
+            _dependencyDirPath = dependencyDirPath;
+        }
+
+        protected override Assembly Load(AssemblyName assemblyName)
+        {
+            // We do the simple logic here of looking for an assembly of the given name
+            // in the configured dependency directory.
+            string assemblyPath = Path.Combine(
+                _dependencyDirPath,
+                $"{assemblyName.Name}.dll");
+
+            if (File.Exists(assemblyPath))
+            {
+                Console.WriteLine($"Loading assembly {assemblyName.Name} from {assemblyPath}");
+                // The ALC must use inherited methods to load assemblies.
+                // Assembly.Load*() won't work here.
+                return LoadFromAssemblyPath(assemblyPath);
+            }
+
+            // For other assemblies, return null to allow other resolutions to continue.
+            return null;
+        }
+    }

src/TokenMagician/ModuleResolveEventHandler.cs

@@ -0,0 +1,58 @@
+using System.Management.Automation;
+using System.Reflection;
+using System.Runtime.Loader;
+
+namespace TokenMagician;
+
+/// <summary>
+/// A class that initializes the module when it is imported into the session.
+/// </summary>
+public class ModuleResolveEventHandler : IModuleAssemblyInitializer, IModuleAssemblyCleanup
+{
+    // Get the path of the dependency directory.
+        // In this case we find it relative to the AlcModule.Cmdlets.dll location
+        private static readonly string s_dependencyDirPath = Path.GetFullPath(Path.GetDirectoryName(Assembly.GetExecutingAssembly().Location)!);
+
+        private static readonly ModuleAssemblyLoadContext s_dependencyAlc =
+            new ModuleAssemblyLoadContext(s_dependencyDirPath);
+    public void OnImport()
+    {
+        // This is called when the module is imported into the session
+        // and can be used to initialize the module.
+        Console.WriteLine("Module imported");
+        AssemblyLoadContext.Default.Resolving += ResolveAssembly;
+    }
+
+    public void OnRemove(PSModuleInfo module)
+    {
+        // This is called when the module is removed from the session
+        // and can be used to cleanup the module.
+        Console.WriteLine("Module removed");
+        AssemblyLoadContext.Default.Resolving -= ResolveAssembly;
+    }
+
+    private static Assembly ResolveAssembly(AssemblyLoadContext defaultAlc, AssemblyName assemblyToResolve)
+    {
+        // We only want to resolve the Alc.Engine.dll assembly here.
+        // Because this will be loaded into the custom ALC,
+        // all of *its* dependencies will be resolved
+        // by the logic we defined for that ALC's implementation.
+        //
+        // Note that we are safe in our assumption that the name is enough
+        // to distinguish our assembly here,
+        // since it's unique to our module.
+        // There should be no other AlcModule.Engine.dll on the system.
+        if (!File.Exists(Path.Combine(s_dependencyDirPath, $"{assemblyToResolve.Name}.dll")))
+        {
+            Console.WriteLine($"Assembly {assemblyToResolve.Name} not found in {s_dependencyDirPath}");
+            return null;
+        }
+
+        // Allow our ALC to handle the directory discovery concept
+        //
+        // This is where Alc.Engine.dll is loaded into our custom ALC
+        // and then passed through into PowerShell's ALC,
+        // becoming the bridge between both
+        return s_dependencyAlc.LoadFromAssemblyName(assemblyToResolve);
+    }
+}

src/TokenMagician/TokenMagician.psd1

@@ -2,7 +2,7 @@
     # Script module or binary module file associated with this manifest.
     # This loads the psm1 file, which in turn loads the TokenMagician.Loader.dll which will then load the actual module.
     # This is to setup the Assembly Load Context for the module and its dependencies.
-    RootModule = 'TokenMagician.psm1'
+    RootModule = 'TokenMagician.dll'
 
     # Version number of this module.
     ModuleVersion = '0.1.0'
@@ -59,25 +59,25 @@
     # FunctionsToExport = @()
 
     # Cmdlets to export from this module.
-    CmdletsToExport = @(
-        "Get-TmMsiToken"
-    )
+    # CmdletsToExport = @(
+    #     "Get-TmMsiToken"
+    # )
 
     # Variables to export from this module.
     # VariablesToExport = @()
 
     # Aliases to export from this module.
-    AliasesToExport = @(
-        "Get-MsiToken"
-    )
+    # AliasesToExport = @(
+    #     "Get-MsiToken"
+    # )
 
     # List of all files included in this module.
-    FileList = @(
-        "TokenMagician.psd1",
-        "TokenMagician.psm1",
-        "TokenMagician.dll-Help.xml",
-        "TokenMagician.dll"
-    )
+    # FileList = @(
+    #     "TokenMagician.psd1",
+    #     "TokenMagician.psm1",
+    #     "TokenMagician.dll-Help.xml",
+    #     "TokenMagician.dll"
+    # )
 
     # Private data to pass to the module specified in RootModule/ModuleToProcess.
     PrivateData = @{