fix: prevent duplicate setting error dialogs when global scope is deferred

Add a module-level warnedSettings Set in notifyUserOfSettingErrors to skip
settings that have already been warned about. This handles the edge case
where a user-level misconfiguration (e.g. defaultEnvManager) produces
errors in both workspace and deferred global scope resolution.

Addresses review feedback from StellaHuang95 on PR #1456.

Author: eleanorjboyd

src/features/interpreterSelection.ts

@@ -407,12 +407,26 @@ export async function applyInitialEnvironmentSelection(
 /**
  * Notify the user when their configured settings could not be applied.
  * Shows a warning message with an option to open settings.
+ * Tracks already-warned settings to avoid duplicate dialogs (e.g., when
+ * the same user-level misconfiguration is hit by both workspace and
+ * deferred global scope resolution).
  */
+const warnedSettings = new Set<string>();
+
+export function resetSettingWarnings(): void {
+    warnedSettings.clear();
+}
+
 async function notifyUserOfSettingErrors(errors: SettingResolutionError[]): Promise<void> {
     // Group errors by setting type to avoid spamming the user
     const uniqueSettings = [...new Set(errors.map((e) => e.setting))];
 
     for (const setting of uniqueSettings) {
+        if (warnedSettings.has(setting)) {
+            continue;
+        }
+        warnedSettings.add(setting);
+
         const settingErrors = errors.filter((e) => e.setting === setting);
         const firstError = settingErrors[0];
 

src/test/features/interpreterSelection.unit.test.ts

@@ -11,6 +11,7 @@ import * as workspaceApis from '../../common/workspace.apis';
 import {
     applyInitialEnvironmentSelection,
     registerInterpreterSettingsChangeListener,
+    resetSettingWarnings,
     resolveEnvironmentByPriority,
     resolveGlobalEnvironmentByPriority,
 } from '../../features/interpreterSelection';
@@ -552,6 +553,7 @@ suite('Interpreter Selection - applyInitialEnvironmentSelection', () => {
 
     setup(() => {
         sandbox = sinon.createSandbox();
+        resetSettingWarnings();
 
         mockVenvManager = {
             id: 'ms-python.python:venv',