Fix: Remove global context that caused "add as Python Project" menu to disappear after single use (#724)

The "add as Python Project" context menu item was disappearing after
being used once and only reappearing after a full window reload.

## Root Cause

The issue was caused by improper management of the global VS Code
context `python-envs:isExistingProject`. The context menu visibility was
controlled by the condition:

```json
"when": "explorerViewletVisible && explorerResourceIsFolder && !python-envs:isExistingProject"
```

During command execution, the code would set this global context:

```typescript
commands.executeCommand('setContext', 'python-envs:isExistingProject', isExistingProject(resource));
```

Once this context was set to `true` for any resource, it would prevent
the menu from appearing for all subsequent right-clicks, regardless of
the target folder.

## Solution

- **Removed** the global context setting logic from the
`addPythonProjectGivenResource` command
- **Updated** the context menu conditions in `package.json` to simply
check for folder/file type without the problematic context condition
- **Preserved** existing duplicate detection logic that gracefully
handles attempts to add already-existing projects

The menu will now consistently appear for folders and `.py` files. If
users attempt to add an already-existing project, the existing error
handling shows a "No new projects found" warning.

## Changes

- `src/extension.ts`: Removed context setting logic and unused helper
function (11 lines)
- `package.json`: Simplified context menu conditions (2 lines)

Fixes #723.

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Author: Copilot

package.json

@@ -489,12 +489,12 @@
                 {
                     "command": "python-envs.addPythonProjectGivenResource",
                     "group": "inline",
-                    "when": "explorerViewletVisible && explorerResourceIsFolder && !python-envs:isExistingProject"
+                    "when": "explorerViewletVisible && explorerResourceIsFolder"
                 },
                 {
                     "command": "python-envs.addPythonProjectGivenResource",
                     "group": "inline",
-                    "when": "explorerViewletVisible && resourceExtname == .py && !python-envs:isExistingProject"
+                    "when": "explorerViewletVisible && resourceExtname == .py"
                 }
             ],
             "editor/title/run": [

src/extension.ts

@@ -189,14 +189,6 @@ export async function activate(context: ExtensionContext): Promise<PythonEnviron
     const projectManager: PythonProjectManager = new PythonProjectManagerImpl();
     context.subscriptions.push(projectManager);
 
-    // Helper function to check if a resource is an existing Python project
-    const isExistingProject = (uri: Uri | undefined): boolean => {
-        if (!uri) {
-            return false;
-        }
-        return projectManager.get(uri) !== undefined;
-    };
-
     const envVarManager: EnvVarManager = new PythonEnvVariableManager(projectManager);
     context.subscriptions.push(envVarManager);
 
@@ -323,11 +315,6 @@ export async function activate(context: ExtensionContext): Promise<PythonEnviron
             });
         }),
         commands.registerCommand('python-envs.addPythonProjectGivenResource', async (resource) => {
-            // Set context to show/hide menu item depending on whether the resource is already a Python project
-            if (resource instanceof Uri) {
-                commands.executeCommand('setContext', 'python-envs:isExistingProject', isExistingProject(resource));
-            }
-
             await addPythonProjectCommand(resource, projectManager, envManagers, projectCreators);
             const totalProjectCount = projectManager.getProjects().length + 1;
             sendTelemetryEvent(EventNames.ADD_PROJECT, undefined, {

src/features/creators/autoFindProjects.ts

@@ -83,9 +83,17 @@ export class AutoFindProjects implements PythonProjectCreator {
 
         if (filtered.length === 0) {
             // No new projects found that are not already in the project manager
-            traceInfo('All discovered projects are already registered in the project manager');
+            traceInfo(
+                `All selected resources are already registered in the project manager: ${files
+                    .map((uri) => uri.fsPath)
+                    .join(', ')}`,
+            );
             setImmediate(() => {
-                showWarningMessage('No new projects found');
+                if (files.length === 1) {
+                    showWarningMessage(`${files[0].fsPath} already exists as project.`);
+                } else {
+                    showWarningMessage('Selected resources already exist as projects.');
+                }
             });
             return;
         }

src/features/creators/existingProjects.ts

@@ -56,9 +56,17 @@ export class ExistingProjects implements PythonProjectCreator {
 
         if (filtered.length === 0) {
             // No new projects found that are not already in the project manager
-            traceInfo('All discovered projects are already registered in the project manager');
+            const formattedProjectPaths =
+                existingAddUri === undefined ? 'None' : existingAddUri.map((uri) => uri.fsPath).join(', ');
+            traceInfo(
+                `All selected resources are already registered in the project manager. Resources selected: ${formattedProjectPaths}`,
+            );
             setImmediate(() => {
-                showWarningMessage('No new projects found');
+                if (existingAddUri && existingAddUri.length === 1) {
+                    showWarningMessage(`Selected resource already exists as project.`);
+                } else {
+                    showWarningMessage('Selected resources already exist as projects.');
+                }
             });
             return;
         }