feat: Adds os-locale package for improved language detection (#460)

Introduces the `os-locale` package to enhance the application's ability to detect the user's default language.

This change allows the application to prioritize VS Code's configured language, falling back to the operating system's locale if necessary.

Additionally, it updates the pnpm-lock file to include the new dependency and modifies the package.json accordingly.

This improvement aims to provide a more localized experience for users across different languages.

Co-authored-by: xjm <[email protected]>

Author: xiaojingming

pnpm-lock.yaml

@@ -22,6 +22,7 @@ import { Task } from "../task/Task"
 import { formatReminderSection } from "./reminder"
 import { getShell } from "../../utils/shell"
 import { getOperatingSystem } from "../../utils/zgsmUtils"
+import { defaultLang } from "../../utils/language"
 
 export async function getEnvironmentDetails(cline: Task, includeFileDetails: boolean = false) {
 	let details = ""
@@ -235,7 +236,7 @@ export async function getEnvironmentDetails(cline: Task, includeFileDetails: boo
 	const modeDetails = await getFullModeDetails(currentMode, customModes, customModePrompts, {
 		cwd: cline.cwd,
 		globalCustomInstructions: promptSuggestion + simpleAskSuggestion + shellSuggestion + globalCustomInstructions,
-		language: language ?? formatLanguage(vscode.env.language),
+		language: language ?? formatLanguage(await defaultLang()),
 	})
 	details += `\n\n# Operating System\n${getOperatingSystem()}`
 	details += `\n\n# Default Shell\n${getShell()}`

src/core/environment/getEnvironmentDetails.ts

@@ -53,6 +53,7 @@ import { defaultModeSlug, modes, Mode } from "../../../shared/modes"
 import "../../../utils/path"
 import { addCustomInstructions } from "../sections/custom-instructions"
 import { MultiSearchReplaceDiffStrategy } from "../../diff/strategies/multi-search-replace"
+import { resetLanguageCache } from "../../../utils/language"
 
 // Mock the sections
 vi.mock("../sections/modes", () => ({
@@ -394,6 +395,8 @@ describe("SYSTEM_PROMPT", () => {
 
 	it("should include vscode language in custom instructions", async () => {
 		// Mock vscode.env.language
+		resetLanguageCache()
+
 		const vscode = vi.mocked(await import("vscode")) as any
 		vscode.env = { language: "es" }
 		// Ensure workspace mock is maintained
@@ -444,6 +447,8 @@ describe("SYSTEM_PROMPT", () => {
 
 		// Reset mock
 		vscode.env = { language: "en" }
+		resetLanguageCache()
+
 		vscode.workspace = {
 			workspaceFolders: [
 				{

src/core/prompts/__tests__/system-prompt.spec.ts

@@ -28,6 +28,7 @@ import {
 	addCustomInstructions,
 	markdownFormattingSection,
 } from "./sections"
+import { defaultLang } from "../../utils/language"
 
 // Helper function to get prompt component, filtering out empty objects
 export function getPromptComponent(
@@ -125,7 +126,7 @@ ${getSystemInfoSection(cwd)}
 ${getObjectiveSection(codeIndexManager, experiments)}
 
 ${await addCustomInstructions(baseInstructions, globalCustomInstructions || "", cwd, mode, {
-	language: language ?? formatLanguage(vscode.env.language),
+	language: language ?? formatLanguage(await defaultLang()),
 	rooIgnoreInstructions,
 	settings,
 })}`
@@ -162,7 +163,7 @@ export const SYSTEM_PROMPT = async (
 	const variablesForPrompt: PromptVariables = {
 		workspace: cwd,
 		mode: mode,
-		language: language ?? formatLanguage(vscode.env.language),
+		language: language ?? formatLanguage(await defaultLang()),
 		shell: vscode.env.shell,
 		operatingSystem: os.type(),
 	}
@@ -188,7 +189,7 @@ export const SYSTEM_PROMPT = async (
 			cwd,
 			mode,
 			{
-				language: language ?? formatLanguage(vscode.env.language),
+				language: language ?? formatLanguage(await defaultLang()),
 				rooIgnoreInstructions,
 				settings,
 			},

src/core/prompts/system.ts

@@ -97,6 +97,7 @@ import { ZgsmAuthCommands } from "../costrict/auth"
 import { getClientId } from "../../utils/getClientId"
 import { defaultCodebaseIndexEnabled } from "../../services/code-index/constants"
 import { CodeReviewService, ReviewTargetType } from "../costrict/code-review"
+import { defaultLang } from "../../utils/language"
 
 /**
  * https://github.com/microsoft/vscode-webview-ui-toolkit-samples/blob/main/default/weather-webview/src/providers/WeatherViewProvider.ts
@@ -1913,7 +1914,7 @@ export class ClineProvider
 			telemetryKey,
 			machineId,
 			showRooIgnoredFiles: showRooIgnoredFiles ?? false,
-			language: language ?? formatLanguage(vscode.env.language),
+			language: language ?? formatLanguage(await defaultLang()),
 			renderContext: this.renderContext,
 			maxReadFileLine: maxReadFileLine ?? 500,
 			maxImageFileSize: maxImageFileSize ?? 5,
@@ -2112,7 +2113,7 @@ export class ClineProvider
 			terminalZdotdir: stateValues.terminalZdotdir ?? false,
 			terminalCompressProgressBar: stateValues.terminalCompressProgressBar ?? true,
 			mode: stateValues.mode ?? defaultModeSlug,
-			language: stateValues.language ?? formatLanguage(vscode.env.language),
+			language: stateValues.language ?? formatLanguage(await defaultLang()),
 			mcpEnabled: stateValues.mcpEnabled ?? true,
 			enableMcpServerCreation: stateValues.enableMcpServerCreation ?? true,
 			alwaysApproveResubmit: stateValues.alwaysApproveResubmit ?? false,

src/core/webview/ClineProvider.ts

@@ -16,6 +16,7 @@ import { Task, TaskOptions } from "../../task/Task"
 import { safeWriteJson } from "../../../utils/safeWriteJson"
 
 import { ClineProvider } from "../ClineProvider"
+import { resetLanguageCache } from "../../../utils/language"
 
 // Mock setup must come before imports.
 vi.mock("../../prompts/sections/custom-instructions")
@@ -769,11 +770,14 @@ describe("ClineProvider", () => {
 	})
 
 	test("language is set to VSCode language", async () => {
+		resetLanguageCache()
 		// Mock VSCode language as Spanish
 		;(vscode.env as any).language = "pt-BR"
 
 		const state = await provider.getState()
 		expect(state.language).toBe("pt-BR")
+		;(vscode.env as any).language = "en"
+		resetLanguageCache()
 	})
 
 	test("diffEnabled defaults to true when not set", async () => {

src/core/webview/__tests__/ClineProvider.spec.ts

@@ -43,6 +43,7 @@ import {
 } from "./activate"
 import { initializeI18n } from "./i18n"
 import { getCommand } from "./utils/commands"
+import { defaultLang } from "./utils/language"
 
 /**
  * Built using https://github.com/microsoft/vscode-webview-ui-toolkit
@@ -86,7 +87,7 @@ export async function activate(context: vscode.ExtensionContext) {
 	const mdmService = await MdmService.createInstance(cloudLogger)
 
 	// Initialize i18n for internationalization support.
-	initializeI18n(context.globalState.get("language") ?? formatLanguage(vscode.env.language))
+	initializeI18n(context.globalState.get("language") ?? formatLanguage(await defaultLang()))
 
 	// Initialize terminal shell execution handlers.
 	TerminalRegistry.initialize()

src/extension.ts

@@ -733,6 +733,7 @@
 		"node-ipc": "^12.0.0",
 		"ollama": "^0.5.17",
 		"openai": "^5.12.2",
+		"os-locale": "^6.0.2",
 		"os-name": "^6.0.0",
 		"p-limit": "^6.2.0",
 		"p-wait-for": "^5.0.2",

src/package.json

@@ -0,0 +1,48 @@
+import * as osLocale from "os-locale"
+import * as vscode from "vscode"
+
+/**
+ * Language cache variable to store the obtained language result.
+ * Type is Promise<string> | null, initially null indicates not fetched yet.
+ */
+let languageCache: Promise<string> | null = null
+
+/**
+ * Reset the language cache. Used primarily for testing.
+ */
+export const resetLanguageCache = (): void => {
+	languageCache = null
+}
+
+/**
+ * Get the default language for the application.
+ * First checks VS Code's configured language, uses it if not English.
+ * Otherwise falls back to the operating system's locale.
+ * @returns Promise with the determined language string
+ */
+async function getDefaultLanguage(): Promise<string> {
+	const vscodeLanguage = vscode.env.language
+	if (vscodeLanguage && !vscodeLanguage.toLowerCase().startsWith("en")) {
+		console.log(`[language] Using VS Code language: ${vscodeLanguage}`)
+		return vscodeLanguage
+	}
+
+	const osLang = await osLocale.osLocale()
+	console.log(`[language] VS Code language is English or not set, determined OS locale: ${osLang}`)
+	return osLang
+}
+
+/**
+ * Cached function to get the default language.
+ * If the language is not yet fetched, calls getDefaultLanguage() and caches the result.
+ * Subsequent calls directly return the cached result.
+ * @returns Promise with the determined language string
+ */
+export const defaultLang = (): Promise<string> => {
+	if (!languageCache) {
+		console.log("[language] Fetching default language...")
+		languageCache = getDefaultLanguage()
+	}
+
+	return languageCache
+}

src/utils/language.ts

@@ -205,7 +205,7 @@ export const ExtensionStateContextProvider: React.FC<{ children: React.ReactNode
 		useZgsmCustomConfig: false,
 		zgsmCodebaseIndexEnabled: true,
 		fuzzyMatchThreshold: 1.0,
-		language: "en", // Default language code
+		language: "en", // Default fallback language (will be updated from extension)
 		writeDelayMs: 1000,
 		browserViewportSize: "900x600",
 		screenshotQuality: 75,
@@ -344,6 +344,10 @@ export const ExtensionStateContextProvider: React.FC<{ children: React.ReactNode
 					if ((newState as any).includeTaskHistoryInEnhance !== undefined) {
 						setIncludeTaskHistoryInEnhance((newState as any).includeTaskHistoryInEnhance)
 					}
+					// Update language if present in state message
+					if (newState.language !== undefined) {
+						setState((prevState) => ({ ...prevState, language: newState.language }))
+					}
 					// Handle marketplace data if present in state message
 					if (newState.marketplaceItems !== undefined) {
 						setMarketplaceItems(newState.marketplaceItems)