Remove source guessing workaround

src/compiler/preprocess/index.ts

@@ -160,29 +160,6 @@ function decoded_sourcemap_from_generator(generator: any) {
 	return map;
 }
 
-/**
- * Heuristic used to find index of component source inside source map sources.
- */
-function guess_source_index(
-	file_basename: string,
-	decoded_map: DecodedSourceMap
-): number {
-	if (!file_basename) {
-		return decoded_map.sources.findIndex(source => !source);
-	}
-	// different tools produce different sources
-	// (file name, relative path, absolute path)
-	const index = decoded_map.sources.findIndex(source => {
-		const source_basename = source && get_file_basename(source);
-		return source_basename === file_basename;
-	});
-	if (index !== -1) {
-		// also normalize it in on source map
-		decoded_map.sources[index] = file_basename;
-	}
-	return index;
-}
-
 /**
  * Convert a preprocessor output and its leading prefix and trailing suffix into StringWithSourceMap
  */
@@ -214,7 +191,7 @@ function get_replacement(
 			decoded_map = decoded_sourcemap_from_generator(decoded_map);
 		}
 		// offset only segments pointing at original component source
-		const source_index = guess_source_index(file_basename, decoded_map);
+		const source_index = decoded_map.sources.findIndex(source => source === file_basename);
 		sourcemap_add_offset(decoded_map, get_location(offset + prefix.length), source_index);
 	}
 	const processed_with_map = StringWithSourcemap.from_processed(processed.code, decoded_map);

test/sourcemaps/samples/external/test.js

@@ -14,7 +14,7 @@ export function test({ assert, input, preprocessed }) {
 				line: sourceLoc.line + 1,
 				column: sourceLoc.column
 			},
-			`failed to locate "${code}"`
+			`failed to locate "${code}" in "${filename}"`
 		);
 	};
 

test/sourcemaps/samples/guess-source/_config.js

@@ -1,19 +0,0 @@
-import { magic_string_bundle } from '../../helpers';
-
-export const PREPEND = 'console.log("COUNTER_START")';
-export const APPEND = 'console.log("COUNTER_END")';
-
-export default {
-	js_map_sources: ['input.svelte', 'src/prepend.js', 'src/append.js'],
-	preprocess: [
-		{
-			script: ({ content }) => {
-				return magic_string_bundle([
-					{ filename: 'src/prepend.js', code: PREPEND },
-					{ filename: 'src/input.svelte', code: content },
-					{ filename: 'src/append.js', code: APPEND }
-				]);
-			}
-		}
-	]
-};

test/sourcemaps/samples/guess-source/input.svelte

@@ -1,6 +0,0 @@
-<script lang="ts">
-	let count = 3;
-</script>
-
-<h1>Hello world!</h1>
-<div>Counter value: {count}</div>

test/sourcemaps/samples/guess-source/test.js

@@ -1,30 +0,0 @@
-import { getLocator } from 'locate-character';
-import { APPEND, PREPEND } from './_config';
-
-export function test({ assert, input, preprocessed }) {
-
-	const assertMapped = (locateInput, code, filename) => {
-		const sourceLoc = locateInput(code);
-		const transformedLoc = preprocessed.locate_1(code);
-		assert.deepEqual(
-			preprocessed.mapConsumer.originalPositionFor(transformedLoc),
-			{
-				source: filename,
-				name: null,
-				line: sourceLoc.line + 1,
-				column: sourceLoc.column
-			},
-			`failed to locate "${code}"`
-		);
-	};
-	
-	// Transformed script, main file
-	assertMapped(input.locate, 'let count = 3;', 'input.svelte');
-
-	// Untouched markup, main file
-	assertMapped(input.locate, '<h1>Hello world!</h1>', 'input.svelte');
-
-	// External files
-	assertMapped(getLocator(PREPEND), '"COUNTER_START"', 'src/prepend.js');
-	assertMapped(getLocator(APPEND), '"COUNTER_END"', 'src/append.js');
-}