based on copilot comments

Author: eleanorjboyd

src/client/testing/common/debugLauncher.ts

@@ -118,19 +118,27 @@ export class DebugLauncher implements ITestDebugLauncher {
             }),
         );
 
+        // Clean up event subscriptions when debugging completes (success, failure, or cancellation)
+        deferred.promise.finally(() => {
+            disposables.forEach((d) => d.dispose());
+        });
+
         // Start the debug session
-        const started = await debugManager.startDebugging(workspaceFolder, launchArgs, sessionOptions);
+        let started = false;
+        try {
+            started = await debugManager.startDebugging(workspaceFolder, launchArgs, sessionOptions);
+        } catch (error) {
+            traceError('Error starting debug session', error);
+            deferred.reject(error);
+            callCallbackOnce();
+            return deferred.promise;
+        }
         if (!started) {
             traceError('Failed to start debug session');
             deferred.resolve();
             callCallbackOnce();
         }
 
-        // Clean up event subscriptions when debugging completes (success, failure, or cancellation)
-        deferred.promise.finally(() => {
-            disposables.forEach((d) => d.dispose());
-        });
-
         return deferred.promise;
     }
 

src/client/testing/testController/common/testProjectRegistry.ts

@@ -293,7 +293,7 @@ export class TestProjectRegistry {
                 const parentPath = parent.projectUri.fsPath;
                 const childPath = child.projectUri.fsPath;
 
-                if (childPath.startsWith(parentPath + path.sep)) {
+                if (isParentPath(parentPath, childPath)) {
                     nestedPaths.push(childPath);
                     traceVerbose(`[test-by-project] Nested: ${child.projectName} under ${parent.projectName}`);
                 }

src/client/testing/testController/controller.ts

@@ -306,12 +306,10 @@ export class PythonTestController implements ITestController, IExtensionSingleAc
                 }
             }
 
-            // Clear registry and re-discover all projects for the workspace
-            this.projectRegistry.clearWorkspace(workspace.uri);
-            await this.projectRegistry.discoverAndRegisterProjects(workspace.uri);
-
-            // Re-run test discovery for the workspace to populate fresh test items
-            await this.discoverTestsInWorkspace(workspace.uri);
+            // Re-discover all projects and tests for the workspace in a single pass.
+            // discoverAllProjectsInWorkspace is responsible for clearing/re-registering
+            // projects and performing test discovery for the workspace.
+            await this.discoverAllProjectsInWorkspace(workspace.uri);
         }
     }