fix (indentation): replace beforeStart with codeBefore

lib/rules/indentation/__tests__/document-with-roots.js

@@ -0,0 +1,37 @@
+'use strict';
+
+const { parse: postcssParse, stringify, Document, Input } = require('postcss');
+const { ruleName } = require('..');
+
+const parse = (source, opts) => {
+	const doc = new Document();
+	const root = postcssParse(source, opts);
+
+	root.parent = doc;
+	root.document = doc;
+	doc.nodes.push(root);
+	doc.source = {
+		input: new Input(source, opts),
+		start: { line: 1, column: 1, offset: 0 },
+	};
+
+	return doc;
+};
+
+testRule({
+	ruleName,
+	config: [2],
+	fix: true,
+	customSyntax: {
+		parse,
+		stringify,
+	},
+
+	accept: [
+		{
+			code: '.foo {\n' + '  color: hotpink;\n' + '}',
+		},
+	],
+
+	reject: [],
+});

lib/rules/indentation/index.js

@@ -93,7 +93,9 @@ const rule = (primary, secondaryOptions = {}, context) => {
 			// it is some other kind of separation, checked by some separate rule
 			if (
 				(lastIndexOfNewline !== -1 ||
-					(isFirstChild && (!getDocument(parent) || parent.raws.beforeStart.endsWith('\n')))) &&
+					(isFirstChild &&
+						(!getDocument(parent) ||
+							(parent.raws.codeBefore && parent.raws.codeBefore.endsWith('\n'))))) &&
 				before.slice(lastIndexOfNewline + 1) !== expectedOpeningBraceIndentation
 			) {
 				if (context.fix) {
@@ -607,7 +609,7 @@ function inferRootIndentLevel(root, baseIndentLevel, indentSize) {
 		let source = root.source.input.css;
 
 		source = source.replace(/^[^\r\n]+/, (firstLine) => {
-			const match = /(?:^|\n)([ \t]*)$/.exec(root.raws.beforeStart);
+			const match = root.raws.codeBefore && /(?:^|\n)([ \t]*)$/.exec(root.raws.codeBefore);
 
 			if (match) {
 				return match[1] + firstLine;
@@ -628,7 +630,7 @@ function inferRootIndentLevel(root, baseIndentLevel, indentSize) {
 	}
 
 	const indents = [];
-	const foundIndents = /(?:^|\n)([ \t]*)\S/m.exec(root.raws.beforeStart);
+	const foundIndents = root.raws.codeBefore && /(?:^|\n)([ \t]*)\S/m.exec(root.raws.codeBefore);
 
 	// The indent level of the CSS code block in non-CSS-like files is determined by the shortest indent of non-empty line.
 	if (foundIndents) {