Fix string formatter handling of log symbols for non-Unicode termin…

…als (#7981)

.changeset/four-cameras-dream.md

@@ -0,0 +1,5 @@
+---
+"stylelint": patch
+---
+
+Fixed: `string` formatter handling of log symbols for non-Unicode terminals

lib/formatters/__tests__/stringFormatter.test.mjs

@@ -1,8 +1,10 @@
 import process from 'node:process';
 
+import stripAnsi from 'strip-ansi';
 import { stripIndent } from 'common-tags';
 
 import { getCleanFormatterOutput } from '../../testUtils/getCleanOutput.mjs';
+import isUnicodeSupported from '../../utils/isUnicodeSupported.mjs';
 import stringFormatter from '../stringFormatter.mjs';
 
 describe('stringFormatter', () => {
@@ -57,6 +59,32 @@ path/to/file.css
 × 1 problem (1 error, 0 warnings)`);
 	});
 
+	it('outputs symbols depending on the unicode support', () => {
+		const results = [
+			{
+				source: 'path/to/file.css',
+				warnings: [
+					{
+						line: 1,
+						column: 1,
+						rule: 'bar',
+						severity: 'error',
+						text: 'Unexpected foo',
+					},
+				],
+			},
+		];
+
+		const errorSymbol = isUnicodeSupported() ? '✖' : '×';
+		const output = stripAnsi(stringFormatter(results, { ruleMetadata: {} })).trim();
+
+		expect(output).toBe(stripIndent`
+path/to/file.css
+  1:1  ${errorSymbol}  Unexpected foo  bar
+
+${errorSymbol} 1 problem (1 error, 0 warnings)`);
+	});
+
 	it('outputs fixable error and warning counts', () => {
 		const results = [
 			{

lib/formatters/stringFormatter.cjs

@@ -9,6 +9,7 @@ const stringWidth = require('string-width');
 const table = require('table');
 const validateTypes = require('../utils/validateTypes.cjs');
 const calcSeverityCounts = require('./calcSeverityCounts.cjs');
+const isUnicodeSupported = require('../utils/isUnicodeSupported.cjs');
 const pluralize = require('../utils/pluralize.cjs');
 const preprocessWarnings = require('./preprocessWarnings.cjs');
 const terminalLink = require('./terminalLink.cjs');
@@ -22,22 +23,24 @@ const MARGIN_WIDTHS = 9;
  * @param {string} s
  * @returns {string}
  */
-function nope(s) {
+function identity(s) {
 	return s;
 }
 
 const levelColors = {
 	info: blue,
 	warning: yellow,
 	error: red,
-	success: nope,
+	success: identity,
 };
 
+const supportsUnicode = isUnicodeSupported();
+
 const symbols = {
-	info: blue('ℹ'),
-	warning: yellow('⚠'),
-	error: red('✖'),
-	success: green('✔'),
+	info: blue(supportsUnicode ? 'ℹ' : 'i'),
+	warning: yellow(supportsUnicode ? '⚠' : '‼'),
+	error: red(supportsUnicode ? '✖' : '×'),
+	success: green(supportsUnicode ? '✔' : '√'),
 };
 
 /**

lib/formatters/stringFormatter.mjs

@@ -7,6 +7,7 @@ import table from 'table';
 
 import { assertNumber } from '../utils/validateTypes.mjs';
 import calcSeverityCounts from './calcSeverityCounts.mjs';
+import isUnicodeSupported from '../utils/isUnicodeSupported.mjs';
 import pluralize from '../utils/pluralize.mjs';
 import preprocessWarnings from './preprocessWarnings.mjs';
 import terminalLink from './terminalLink.mjs';
@@ -20,22 +21,24 @@ const MARGIN_WIDTHS = 9;
  * @param {string} s
  * @returns {string}
  */
-function nope(s) {
+function identity(s) {
 	return s;
 }
 
 const levelColors = {
 	info: blue,
 	warning: yellow,
 	error: red,
-	success: nope,
+	success: identity,
 };
 
+const supportsUnicode = isUnicodeSupported();
+
 const symbols = {
-	info: blue('ℹ'),
-	warning: yellow('⚠'),
-	error: red('✖'),
-	success: green('✔'),
+	info: blue(supportsUnicode ? 'ℹ' : 'i'),
+	warning: yellow(supportsUnicode ? '⚠' : '‼'),
+	error: red(supportsUnicode ? '✖' : '×'),
+	success: green(supportsUnicode ? '✔' : '√'),
 };
 
 /**

lib/utils/isUnicodeSupported.cjs

@@ -0,0 +1,32 @@
+// NOTICE: This file is generated by Rollup. To modify it,
+// please instead edit the ESM counterpart and rebuild with Rollup (npm run build).
+'use strict';
+
+const process = require('node:process');
+
+/**
+ * Originally copied from https://github.com/sindresorhus/is-unicode-supported/blob/506f27260df3636555714bf10ed40ab9e6a6c96e/index.js
+ * @version 2.0.0
+ * @summary Detect whether the terminal supports Unicode
+ * @see https://github.com/sindresorhus/is-unicode-supported/pull/1#issuecomment-827321546
+ * @see microsoft/terminal#13680
+ */
+function isUnicodeSupported() {
+	if (process.platform !== 'win32') {
+		return process.env.TERM !== 'linux'; // Linux console (kernel)
+	}
+
+	return (
+		Boolean(process.env.WT_SESSION) || // Windows Terminal
+		Boolean(process.env.TERMINUS_SUBLIME) || // Terminus (<0.2.27)
+		process.env.ConEmuTask === '{cmd::Cmder}' || // ConEmu and cmder
+		process.env.TERM_PROGRAM === 'Terminus-Sublime' ||
+		process.env.TERM_PROGRAM === 'vscode' ||
+		process.env.TERM === 'xterm-256color' ||
+		process.env.TERM === 'alacritty' ||
+		process.env.TERMINAL_EMULATOR === 'JetBrains-JediTerm' ||
+		process.env.TERM?.startsWith('rxvt-unicode') // fork of rxvt
+	);
+}
+
+module.exports = isUnicodeSupported;

lib/utils/isUnicodeSupported.mjs

@@ -0,0 +1,26 @@
+import process from 'node:process';
+
+/**
+ * Originally copied from https://github.com/sindresorhus/is-unicode-supported/blob/506f27260df3636555714bf10ed40ab9e6a6c96e/index.js
+ * @version 2.0.0
+ * @summary Detect whether the terminal supports Unicode
+ * @see https://github.com/sindresorhus/is-unicode-supported/pull/1#issuecomment-827321546
+ * @see microsoft/terminal#13680
+ */
+export default function isUnicodeSupported() {
+	if (process.platform !== 'win32') {
+		return process.env.TERM !== 'linux'; // Linux console (kernel)
+	}
+
+	return (
+		Boolean(process.env.WT_SESSION) || // Windows Terminal
+		Boolean(process.env.TERMINUS_SUBLIME) || // Terminus (<0.2.27)
+		process.env.ConEmuTask === '{cmd::Cmder}' || // ConEmu and cmder
+		process.env.TERM_PROGRAM === 'Terminus-Sublime' ||
+		process.env.TERM_PROGRAM === 'vscode' ||
+		process.env.TERM === 'xterm-256color' ||
+		process.env.TERM === 'alacritty' ||
+		process.env.TERMINAL_EMULATOR === 'JetBrains-JediTerm' ||
+		process.env.TERM?.startsWith('rxvt-unicode') // fork of rxvt
+	);
+}