Add warning messages for the packageManager setting

client/src/client.ts

@@ -238,9 +238,7 @@ export namespace ESLintClient {
 
 			const uri: Uri = Uri.parse(params.source.uri);
 			const workspaceFolder = Workspace.getWorkspaceFolder(uri);
-			const packageManager = await commands.executeCommand<PackageManagers>(
-				'npm.packageManager'
-			);
+			const packageManager = await getPackageManager(uri);
 			const localInstall = {
 				npm: 'npm install eslint',
 				pnpm: 'pnpm install eslint',
@@ -584,6 +582,18 @@ export namespace ESLintClient {
 			return clientOptions;
 		}
 
+		async function getPackageManager(uri: Uri) {
+			const userProvidedPackageManager:PackageManagers = Workspace.getConfiguration('eslint', uri).get('packageManager', 'npm');
+			const detectedPackageMananger = await commands.executeCommand<PackageManagers>('npm.packageManager');
+
+			if (userProvidedPackageManager === detectedPackageMananger) {
+				client.warn('The ESLint setting packageManager is deprecated, and will be removed in the future. Please update your configuration.', {}, true);
+				return detectedPackageMananger;
+			}
+			client.warn('The ESLint setting packageManager is deprecated, and will be removed in the future. We will honor this setting until it is removed.', {}, true);
+			return userProvidedPackageManager;
+		}
+
 		async function readConfiguration(params: ConfigurationParams): Promise<(ConfigurationSettings | null)[]> {
 			if (params.items === undefined) {
 				return [];