[Cherry-pick] [DYN-9082] All Python Engines should be loaded correctly in D4R (#16390)

github-actions[bot] · reddyashish · web-flow · commit 22209cd83cd9 · 2025-07-17T13:50:36.000-04:00
Co-authored-by: reddyashish &lt;43763136+reddyashish@users.noreply.github.com&gt;
diff --git a/src/DynamoPackages/PackageManagerExtension.cs b/src/DynamoPackages/PackageManagerExtension.cs
@@ -23,7 +23,7 @@ public class PackageManagerExtension : IExtension, ILogSource, IExtensionSource
         //TODO should we add a new handler specifically for packages? this is the package manager afterall so maybe not.
         private event Func<string, PackageInfo, IEnumerable<CustomNodeInfo>> RequestLoadCustomNodeDirectoryHandler;
         private Action<IEnumerable<Assembly>> LoadPackagesHandler;
-       
+
         public event Func<string, IExtension> RequestLoadExtension;
         public event Action<IExtension> RequestAddExtension;
         public event Action<ILogMessage> MessageLogged;
@@ -148,6 +148,13 @@ public void Startup(StartupParams startupParams)
             PackageLoader.PackagesLoaded += LoadPackagesHandler;
             PackageLoader.RequestLoadNodeLibrary += RequestLoadNodeLibraryHandler;
             PackageLoader.RequestLoadCustomNodeDirectory += RequestLoadCustomNodeDirectoryHandler;
+
+            if (PythonServices.PythonEngineManager.Instance.AvailableEngines.Count == 0)
+            {
+                PythonServices.PythonEngineManager.Instance.LoadDefaultPythonEngine(AppDomain.CurrentDomain.GetAssemblies().
+                                                                                    FirstOrDefault(a => a != null && a.GetName().Name == PythonServices.PythonEngineManager.CPythonAssemblyName));
+            }
+
             PythonServices.PythonEngineManager.Instance.AvailableEngines.CollectionChanged += PythonEngineAdded;
                 
             var dirBuilder = new PackageDirectoryBuilder(
@@ -236,6 +243,7 @@ public void Ready(ReadyParams sp)
 
         public void Shutdown()
         {
+            PythonServices.PythonEngineManager.Instance.AvailableEngines.Clear();
             PythonServices.PythonEngineManager.Instance.AvailableEngines.CollectionChanged -= PythonEngineAdded;
             //this.Dispose();
         }
diff --git a/src/NodeServices/PythonServices.cs b/src/NodeServices/PythonServices.cs
@@ -192,7 +192,7 @@ private PythonEngineManager()
             AppDomain.CurrentDomain.AssemblyLoad += new AssemblyLoadEventHandler((object sender, AssemblyLoadEventArgs args) => LoadDefaultPythonEngine(args.LoadedAssembly));
         }
 
-        private void LoadDefaultPythonEngine(Assembly a)
+        internal void LoadDefaultPythonEngine(Assembly a)
         {
             if (a == null ||
                 a.GetName().Name != CPythonAssemblyName)

Original file line number	Diff line number	Diff line change
`@@ -192,7 +192,7 @@ private PythonEngineManager()`
`192`	`192`	`AppDomain.CurrentDomain.AssemblyLoad += new AssemblyLoadEventHandler((object sender, AssemblyLoadEventArgs args) => LoadDefaultPythonEngine(args.LoadedAssembly));`
`193`	`193`	`}`
`194`	`194`
`195`		`- private void LoadDefaultPythonEngine(Assembly a)`
	`195`	`+ internal void LoadDefaultPythonEngine(Assembly a)`
`196`	`196`	`{`
`197`	`197`	`if (a == null \|\|`
`198`	`198`	`a.GetName().Name != CPythonAssemblyName)`