Show more info in missing customSyntax warning (#5611)

* Show more info in missing customSyntax warning

* Change markdown syntax

* Update lib/getPostcssResult.js

Co-authored-by: Masafumi Koba <473530+ybiquitous@users.noreply.github.com>

Co-authored-by: Masafumi Koba <473530+ybiquitous@users.noreply.github.com>

lib/__tests__/standalone-syntax.test.js

@@ -9,6 +9,9 @@ const { promises: fs } = require('fs');
 const fixturesPath = replaceBackslashes(path.join(__dirname, 'fixtures'));
 
 it('standalone with postcss-safe-parser', () => {
+	// Hide “When linting something other than CSS...” warning from test
+	jest.spyOn(console, 'warn').mockImplementation(() => {});
+
 	return standalone({
 		files: `${fixturesPath}/syntax_error.*`,
 		config: {
@@ -47,7 +50,9 @@ it('standalone with postcss-safe-parser', () => {
 
 					return fs.writeFile(root.source.input.file, root.source.input.css);
 				}),
-		);
+		).then(() => {
+			jest.restoreAllMocks();
+		});
 	});
 });
 

lib/getPostcssResult.js

@@ -13,23 +13,6 @@ const { promises: fs } = require('fs');
 
 const postcssProcessor = postcss();
 
-const previouslyInferedExtensions = [
-	'html',
-	'js',
-	'jsx',
-	'less',
-	'md',
-	'sass',
-	'sss',
-	'scss',
-	'svelte',
-	'ts',
-	'tsx',
-	'vue',
-	'xml',
-	'xst',
-];
-
 /**
  * @param {StylelintInternalApi} stylelint
  * @param {GetPostcssOptions} options
@@ -145,6 +128,24 @@ function getCustomSyntax(customSyntax) {
 	throw new Error(`Custom syntax must be a string or a Syntax object`);
 }
 
+/** @type {{ [key: string]: string }} */
+const previouslyInferedExtensions = {
+	html: 'postcss-html',
+	js: '@stylelint/postcss-css-in-js',
+	jsx: '@stylelint/postcss-css-in-js',
+	less: 'postcss-less',
+	md: 'postcss-markdown',
+	sass: 'postcss-sass',
+	sss: 'sugarss',
+	scss: 'postcss-scss',
+	svelte: 'postcss-html',
+	ts: '@stylelint/postcss-css-in-js',
+	tsx: '@stylelint/postcss-css-in-js',
+	vue: 'postcss-html',
+	xml: 'postcss-html',
+	xst: 'postcss-html',
+};
+
 /**
  * @param {StylelintInternalApi} stylelint
  * @param {string|undefined} filePath
@@ -160,9 +161,9 @@ function cssSyntax(stylelint, filePath) {
 
 	const extensions = ['css', 'pcss', 'postcss'];
 
-	if (previouslyInferedExtensions.includes(fileExtension)) {
+	if (previouslyInferedExtensions[fileExtension]) {
 		console.warn(
-			'When linting something other than CSS, you should install an appropriate syntax, e.g. postcss-scss, and use the "customSyntax" option',
+			`${filePath}: When linting something other than CSS, you should install an appropriate syntax, e.g. "${previouslyInferedExtensions[fileExtension]}", and use the "customSyntax" option`,
 		);
 	}