Add full source map support to line number selection

.xo-config.json

@@ -2,6 +2,7 @@
 	"ignores": [
 		"media/**",
 		"test/config/fixtures/config-errors/test.js",
+		"test/line-numbers/fixtures/line-numbers.js",
 		"test-tap/fixture/snapshots/test-sourcemaps/build/**",
 		"test-tap/fixture/report/edgecases/ast-syntax-error.cjs",
 		"examples/typescript-*/**/*.ts"

lib/worker/line-numbers.js

@@ -1,5 +1,5 @@
 import * as fs from 'node:fs';
-import {createRequire} from 'node:module';
+import {createRequire, findSourceMap} from 'node:module';
 import {pathToFileURL} from 'node:url';
 
 import callsites from 'callsites';
@@ -60,15 +60,45 @@ function findTest(locations, declaration) {
 
 const range = (start, end) => Array.from({length: end - start + 1}).fill(start).map((element, index) => element + index);
 
+const translate = (sourceMap, pos) => {
+	if (sourceMap === undefined) {
+		return pos;
+	}
+
+	const entry = sourceMap.findEntry(pos.line - 1, pos.column); // Source maps are 0-based
+	return {
+		line: entry.originalLine + 1, // Readjust for Acorn.
+		column: entry.originalColumn,
+	};
+};
+
 export default function lineNumberSelection({file, lineNumbers = []}) {
 	if (lineNumbers.length === 0) {
 		return undefined;
 	}
 
-	const locations = parse(file);
 	const selected = new Set(lineNumbers);
 
+	let locations = parse(file);
+	let lookedForSourceMap = false;
+	let sourceMap;
+
 	return () => {
+		if (!lookedForSourceMap) {
+			lookedForSourceMap = true;
+
+			// The returned function is called *after* the file has been loaded.
+			// Source maps are not available before then.
+			sourceMap = findSourceMap(file);
+
+			if (sourceMap !== undefined) {
+				locations = locations.map(({start, end}) => ({
+					start: translate(sourceMap, start),
+					end: translate(sourceMap, end),
+				}));
+			}
+		}
+
 		// Assume this is called from a test declaration, which is located in the file.
 		// If not… don't select the test!
 		const callSite = callsites().find(callSite => {
@@ -83,10 +113,10 @@ export default function lineNumberSelection({file, lineNumbers = []}) {
 			return false;
 		}
 
-		const start = {
-			line: callSite.getLineNumber(),
-			column: callSite.getColumnNumber() - 1, // Use 0-indexed columns.
-		};
+		const start = translate(sourceMap, {
+			line: callSite.getLineNumber(), // 1-based
+			column: callSite.getColumnNumber() - 1, // Comes out as 1-based, Acorn wants 0-based
+		});
 
 		const test = findTest(locations, start);
 		if (!test) {

test/line-numbers/fixtures/README.md

@@ -0,0 +1,5 @@
+Compile using:
+
+```console
+npx tsc line-numbers.ts --outDir . --sourceMap --module es2020 --moduleResolution node
+```

test/line-numbers/fixtures/line-numbers.ts

@@ -0,0 +1,27 @@
+import test from 'ava'; // eslint-disable-line ava/no-ignored-test-files
+
+test('unicorn', t => {
+	t.pass();
+});
+
+test('rainbow', t => {
+	t.pass();
+});
+
+test.serial('cat', t => {
+	t.pass();
+});
+
+test.todo('dog'); // eslint-disable-line ava/no-todo-test
+
+/* eslint-disable max-statements-per-line, ava/no-inline-assertions */
+test('sun', t => t.pass()); test('moon', t => {
+	t.pass();
+});
+/* eslint-enable max-statements-per-line, ava/no-inline-assertions */
+
+(() => {
+	test('nested call', t => {
+		t.pass();
+	});
+})();