Safer handling for GetLineAndColumnForLocation (#940)

* fix(#936): safer handling for GetLineAndColumnForLocation

* chore: add changeset

.changeset/kind-cheetahs-listen.md

@@ -0,0 +1,5 @@
+---
+'@astrojs/compiler': patch
+---
+
+Fixes a sourcemap-related crash when using multibyte characters

internal/sourcemap/sourcemap.go

@@ -616,7 +616,7 @@ func (b *ChunkBuilder) GetLineAndColumnForLocation(location loc.Loc) []int {
 	for count > 0 {
 		step := count / 2
 		i := originalLine + step
-		if lineOffsetTables[i].byteOffsetToStartOfLine <= location.Start {
+		if len(lineOffsetTables) > i && lineOffsetTables[i].byteOffsetToStartOfLine <= location.Start {
 			originalLine = i + 1
 			count = count - step - 1
 		} else {
@@ -629,7 +629,10 @@ func (b *ChunkBuilder) GetLineAndColumnForLocation(location loc.Loc) []int {
 	line := &lineOffsetTables[originalLine]
 	originalColumn := int(location.Start - line.byteOffsetToStartOfLine)
 	if line.columnsForNonASCII != nil && originalColumn >= int(line.byteOffsetToFirstNonASCII) {
-		originalColumn = int(line.columnsForNonASCII[originalColumn-int(line.byteOffsetToFirstNonASCII)])
+		newColumn := originalColumn - int(line.byteOffsetToFirstNonASCII)
+		if len(line.columnsForNonASCII) > newColumn {
+			originalColumn = int(line.columnsForNonASCII[newColumn])
+		}
 	}
 
 	// 1-based line, 1-based column

packages/compiler/test/parse/multibyte-characters.ts

@@ -0,0 +1,21 @@
+import { test } from 'uvu';
+import * as assert from 'uvu/assert';
+import { parse } from '@astrojs/compiler';
+
+const FIXTURE = `{foo}，`;
+
+test('does not crash', async () => {
+  const result = await parse(FIXTURE);
+  assert.ok(result.ast, 'does not crash');
+});
+
+test('properly maps the position', async () => {
+  const {
+    ast: { children },
+  } = await parse(FIXTURE);
+  const text = children[1];
+  assert.equal(text.position.start.offset, 5, 'properly maps the text start position');
+  assert.equal(text.position.end.offset, 8, 'properly maps the text end position');
+});
+
+test.run();