add tests, fix empty map.sources, cleanup gitignore

.gitignore

@@ -18,10 +18,6 @@ node_modules
 /coverage/
 /coverage.lcov
 /test/*/samples/_
-/test/sourcemaps/samples/*/output.js
-/test/sourcemaps/samples/*/output.js.map
-/test/sourcemaps/samples/*/output.css
-/test/sourcemaps/samples/*/output.css.map
 /yarn-error.log
 _actual*.*
 _output

src/compiler/preprocess/index.ts

@@ -132,7 +132,7 @@ export default async function preprocess(
 	// sourcemap_list is sorted in reverse order from last map (index 0) to first map (index -1)
 	// so we use sourcemap_list.unshift() to add new maps
 	// https://github.com/ampproject/remapping#multiple-transformations-of-a-file
-	const sourcemap_list: Array<Processed['map']> = [];
+	let sourcemap_list: Array<Processed['map']> = [];
 
 	for (const fn of markup) {
 
@@ -213,14 +213,22 @@ export default async function preprocess(
 		sourcemap_list.unshift(res.map);
 	}
 
-	// https://github.com/ampproject/remapping#usage
+	// remapper can throw error
-	// https://github.com/mozilla/source-map#new-sourcemapconsumerrawsourcemap
+	// `Transformation map ${i} must have exactly one source file.`
+	sourcemap_list = sourcemap_list
+		.map(sourcemap => {
+			if ((sourcemap as any).sources.filter(Boolean).length == 0)
+				// fix missing source file
+				(sourcemap as any).sources = [filename];
+			return sourcemap;
+		});
+
 	const map: ReturnType<typeof remapper> =
 		sourcemap_list.length == 0
 			? null
 			: remapper(sourcemap_list as any, () => null, true); // true: skip optional field `sourcesContent`
 
-	if (map) delete map.file; // skip optional field `file`
+	if (map && !map.file) delete map.file; // skip optional field `file`
 
 	return {
 		// TODO return separated output, in future version where svelte.compile supports it:

test/sourcemaps/index.js

@@ -29,11 +29,20 @@ describe("sourcemaps", () => {
 			input.code = fs.readFileSync(inputFile, "utf-8");
 			input.locate = getLocator(input.code);
 
-			const preprocessed = await svelte.preprocess(
+			let preprocessed;
+			try {
+				preprocessed = await svelte.preprocess(
 					input.code,
 					config.preprocess, {
 					filename: "input.svelte"
 				});
+			} catch (error) {
+				preprocessed = {
+					error,
+					code: '',
+					map: null
+				};
+			}
 
 			const { js, css } = svelte.compile(
 				preprocessed.code, {

test/sourcemaps/samples/decoded-sourcemap/_config.js

@@ -0,0 +1,29 @@
+import MagicString from 'magic-string';
+
+function replace(search, replace, content, src, options = {}) {
+	let idx = -1;
+	while ((idx = content.indexOf(search, idx + 1)) != -1) {
+		src.overwrite(idx, idx + search.length, replace, options);
+	}
+}
+
+function result(src, filename) {
+	return {
+		code: src.toString(),
+		map: src.generateDecodedMap({ // return decoded sourcemap
+			source: filename,
+			hires: true,
+			includeContent: false
+		})
+	};
+}
+
+export default {
+	preprocess: {
+		markup: ({ content, filename }) => {
+			const src = new MagicString(content);
+			replace('replace me', 'success', content, src);
+			return result(src, filename);
+		}
+	}
+};

test/sourcemaps/samples/decoded-sourcemap/input.svelte

@@ -0,0 +1,2 @@
+<h1>decoded-sourcemap</h1>
+<div>replace me</div>

test/sourcemaps/samples/decoded-sourcemap/test.js

@@ -0,0 +1,19 @@
+export function test({ assert, input, preprocessed }) {
+
+  const expected = input.locate('replace me');
+
+  const start = preprocessed.locate('success');
+
+  const actualbar = preprocessed.mapConsumer.originalPositionFor({
+    line: start.line + 1,
+    column: start.column
+  });
+
+  assert.deepEqual(actualbar, {
+    source: 'input.svelte',
+    name: null,
+    line: expected.line + 1,
+    column: expected.column
+  });
+
+}

test/sourcemaps/samples/sourcemap-sources/_config.js

@@ -0,0 +1,46 @@
+import MagicString from 'magic-string';
+
+function add(bundle, filename, source) {
+  bundle.addSource({
+    filename: filename,
+    content: new MagicString(source)
+  });
+}
+
+function result(bundle, filename) {
+  return {
+    code: bundle.toString(),
+    map: bundle.generateMap({
+      file: filename,
+      includeContent: true,
+      hires: true
+    })
+  };
+}
+
+export default {
+	preprocess: [
+		{
+			script: ({ content, filename }) => {
+				const bundle = new MagicString.Bundle();
+
+				add(bundle, filename, content);
+				add(bundle, 'foo.js', 'var answer = 42;');
+				add(bundle, 'bar.js', 'console.log(answer);');
+
+        return result(bundle, filename);
+			}
+		},
+		{
+			script: ({ content, filename }) => {
+				const bundle = new MagicString.Bundle();
+
+				add(bundle, filename, content);
+				add(bundle, 'foo2.js', 'var answer2 = 84;');
+				add(bundle, 'bar2.js', 'console.log(answer2);');
+
+        return result(bundle, filename);
+			}
+		}
+	]
+};

test/sourcemaps/samples/sourcemap-sources/input.svelte

@@ -0,0 +1,4 @@
+<script>
+	export let name;
+</script>
+<h1>sourcemap-sources</h1>

test/sourcemaps/samples/sourcemap-sources/test.js

@@ -0,0 +1,12 @@
+export function test({ assert, preprocessed, js, css }) {
+
+	const msg_expected = 'Transformation map 0 must have exactly one source file.';
+
+  assert.notEqual(preprocessed.error, undefined, 'expected preprocessed.error');
+
+	assert.equal(
+		preprocessed.error.message.slice(0, msg_expected.length),
+		msg_expected
+	);
+
+}