Improve when $LANG is set and expand the number of languages supported

src/vs/workbench/api/node/extHostTerminalService.ts

@@ -182,7 +182,7 @@ export class ExtHostTerminalService extends BaseExtHostTerminalService {
 			this._variableResolver,
 			isWorkspaceShellAllowed,
 			pkg.version,
-			terminalConfig.get<boolean>('setLocaleVariables', false),
+			terminalConfig.get<'auto' | 'off' | 'on'>('detectLocale', 'auto'),
 			baseEnv
 		);
 

src/vs/workbench/contrib/terminal/browser/terminal.contribution.ts

@@ -194,10 +194,16 @@ configurationRegistry.registerConfiguration({
 			type: 'number',
 			default: 1000
 		},
-		'terminal.integrated.setLocaleVariables': {
-			markdownDescription: nls.localize('terminal.integrated.setLocaleVariables', "Controls whether locale variables are set at startup of the terminal."),
-			type: 'boolean',
-			default: true
+		'terminal.integrated.detectLocale': {
+			markdownDescription: nls.localize('terminal.integrated.detectLocale', "Controls whether to detect and set the `$LANG` environment variable to a UTF-8 compliant option since VS Code's terminal only supports UTF-8 encoded data coming from the shell."),
+			type: 'string',
+			enum: ['auto', 'off', 'on'],
+			enumDescriptions: [
+				nls.localize('terminal.integrated.detectLocale.auto', "Set the `$LANG` environment variable if the existing variable does not exist or it does not end in `'.UTF-8'`."),
+				nls.localize('terminal.integrated.detectLocale.off', "Do not set the `$LANG` environment variable."),
+				nls.localize('terminal.integrated.detectLocale.on', "Always set the `$LANG` environment variable.")
+			],
+			default: 'auto'
 		},
 		'terminal.integrated.rendererType': {
 			type: 'string',

src/vs/workbench/contrib/terminal/browser/terminalProcessManager.ts

@@ -227,7 +227,7 @@ export class TerminalProcessManager extends Disposable implements ITerminalProce
 		const isWorkspaceShellAllowed = this._configHelper.checkWorkspaceShellPermissions();
 		this._configHelper.showRecommendations(shellLaunchConfig);
 		const baseEnv = this._configHelper.config.inheritEnv ? processEnv : await this._terminalInstanceService.getMainProcessParentEnv();
-		const env = terminalEnvironment.createTerminalEnvironment(shellLaunchConfig, lastActiveWorkspace, envFromConfigValue, this._configurationResolverService, isWorkspaceShellAllowed, this._productService.version, this._configHelper.config.setLocaleVariables, baseEnv);
+		const env = terminalEnvironment.createTerminalEnvironment(shellLaunchConfig, lastActiveWorkspace, envFromConfigValue, this._configurationResolverService, isWorkspaceShellAllowed, this._productService.version, this._configHelper.config.detectLocale, baseEnv);
 
 		const useConpty = this._configHelper.config.windowsEnableConpty && !isScreenReaderModeEnabled;
 		return this._terminalInstanceService.createTerminalProcess(shellLaunchConfig, initialCwd, cols, rows, env, useConpty);

src/vs/workbench/contrib/terminal/common/terminal.ts

@@ -100,7 +100,7 @@ export interface ITerminalConfiguration {
 	fontSize: number;
 	letterSpacing: number;
 	lineHeight: number;
-	setLocaleVariables: boolean;
+	detectLocale: 'auto' | 'off' | 'on';
 	scrollback: number;
 	commandsToSkipShell: string[];
 	cwd: string;

src/vs/workbench/contrib/terminal/common/terminalEnvironment.ts

@@ -51,13 +51,13 @@ function _mergeEnvironmentValue(env: ITerminalEnvironment, key: string, value: s
 	}
 }
 
-export function addTerminalEnvironmentKeys(env: platform.IProcessEnvironment, version: string | undefined, locale: string | undefined, setLocaleVariables: boolean): void {
+export function addTerminalEnvironmentKeys(env: platform.IProcessEnvironment, version: string | undefined, locale: string | undefined, detectLocale: 'auto' | 'off' | 'on'): void {
 	env['TERM_PROGRAM'] = 'vscode';
 	if (version) {
 		env['TERM_PROGRAM_VERSION'] = version;
 	}
-	if (setLocaleVariables) {
-		env['LANG'] = _getLangEnvVariable(locale);
+	if (shouldSetLangEnvVariable(env, detectLocale)) {
+		env['LANG'] = getLangEnvVariable(locale);
 	}
 	env['COLORTERM'] = 'truecolor';
 }
@@ -88,37 +88,87 @@ function resolveConfigurationVariables(configurationResolverService: IConfigurat
 	return env;
 }
 
-function _getLangEnvVariable(locale?: string) {
+export function shouldSetLangEnvVariable(env: platform.IProcessEnvironment, detectLocale: 'auto' | 'off' | 'on'): boolean {
+	if (detectLocale === 'on') {
+		return true;
+	}
+	if (detectLocale === 'auto') {
+		return !env['LANG'] || env['LANG'].search(/\.UTF\-8$/) === -1;
+	}
+	return false; // 'off'
+}
+
+export function getLangEnvVariable(locale?: string): string {
 	const parts = locale ? locale.split('-') : [];
 	const n = parts.length;
 	if (n === 0) {
-		// Fallback to en_US to prevent possible encoding issues.
+		// Fallback to en_US if the locale is unknown
 		return 'en_US.UTF-8';
 	}
 	if (n === 1) {
-		// app.getLocale can return just a language without a variant, fill in the variant for
-		// supported languages as many shells expect a 2-part locale.
+		// The local may only contain the language, not the variant, if this is the case guess the
+		// variant such that it can be used as a valid $LANG variable. The language variant chosen
+		// is the original and/or most prominent with help from
+		// https://stackoverflow.com/a/2502675/1156119
+		// The list of locales was generated by running `locale -a` on macOS
 		const languageVariants: { [key: string]: string } = {
+			af: 'ZA',
+			am: 'ET',
+			be: 'BY',
+			bg: 'BG',
+			ca: 'ES',
 			cs: 'CZ',
+			da: 'DK',
+			// de: 'AT',
+			// de: 'CH',
 			de: 'DE',
+			el: 'GR',
+			// en: 'AU',
+			// en: 'CA',
+			// en: 'GB',
+			// en: 'IE',
+			// en: 'NZ',
 			en: 'US',
 			es: 'ES',
+			et: 'EE',
+			eu: 'ES',
 			fi: 'FI',
+			// fr: 'BE',
+			// fr: 'CA',
+			// fr: 'CH',
 			fr: 'FR',
+			he: 'IL',
+			hr: 'HR',
 			hu: 'HU',
+			hy: 'AM',
+			is: 'IS',
+			// it: 'CH',
 			it: 'IT',
 			ja: 'JP',
+			kk: 'KZ',
 			ko: 'KR',
+			lt: 'LT',
+			// nl: 'BE',
+			nl: 'NL',
+			no: 'NO',
 			pl: 'PL',
+			pt: 'BR',
+			// pt: 'PT',
+			ro: 'RO',
 			ru: 'RU',
 			sk: 'SK',
-			zh: 'CN'
+			sl: 'SI',
+			sr: 'YU',
+			sv: 'SE',
+			tr: 'TR',
+			uk: 'UA',
+			zh: 'CN',
 		};
 		if (parts[0] in languageVariants) {
 			parts.push(languageVariants[parts[0]]);
 		}
 	} else {
-		// Ensure the variant is uppercase
+		// Ensure the variant is uppercase to be a valid $LANG
 		parts[1] = parts[1].toUpperCase();
 	}
 	return parts.join('_') + '.UTF-8';
@@ -294,7 +344,7 @@ export function createTerminalEnvironment(
 	configurationResolverService: IConfigurationResolverService | undefined,
 	isWorkspaceShellAllowed: boolean,
 	version: string | undefined,
-	setLocaleVariables: boolean,
+	detectLocale: 'auto' | 'off' | 'on',
 	baseEnv: platform.IProcessEnvironment
 ): platform.IProcessEnvironment {
 	// Create a terminal environment based on settings, launch config and permissions
@@ -329,7 +379,7 @@ export function createTerminalEnvironment(
 		mergeEnvironments(env, shellLaunchConfig.env);
 
 		// Adding other env keys necessary to create the process
-		addTerminalEnvironmentKeys(env, version, platform.locale, setLocaleVariables);
+		addTerminalEnvironmentKeys(env, version, platform.locale, detectLocale);
 	}
 	return env;
 }