Treat a missing sourcemap as a warning

packages/workbox-build/src/inject-manifest.ts

@@ -19,6 +19,7 @@ import {escapeRegExp} from './lib/escape-regexp';
 import {getFileManifestEntries} from './lib/get-file-manifest-entries';
 import {rebasePath} from './lib/rebase-path';
 import {replaceAndUpdateSourceMap} from './lib/replace-and-update-source-map';
+import {translateURLToSourcemapPaths} from './lib/translate-url-to-sourcemap-paths';
 import {validateInjectManifestOptions} from './lib/validate-options';
 
 // eslint-disable-next-line jsdoc/newline-after-description
@@ -162,31 +163,28 @@ export async function injectManifest(config: unknown): Promise<BuildResult> {
 
   const manifestString = stringify(manifestEntries);
   const filesToWrite: {[key: string]: string} = {};
-  // sourceMapURL returns value type any and could be null.
-  // url is checked before it is used later.
-  const url: string = sourceMapURL.getFrom(swFileContents); // eslint-disable-line
+
+  const url = sourceMapURL.getFrom(swFileContents) as string; // eslint-disable-line
+  // See https://github.com/GoogleChrome/workbox/issues/2957
+  const {destPath, srcPath, warning} = translateURLToSourcemapPaths(
+    url,
+    options.swSrc,
+    options.swDest,
+  );
+  if (warning) {
+    warnings.push(warning);
+  }
+
   // If our swSrc file contains a sourcemap, we would invalidate that
   // mapping if we just replaced injectionPoint with the stringified manifest.
   // Instead, we need to update the swDest contents as well as the sourcemap
   // (assuming it's a real file, not a data: URL) at the same time.
   // See https://github.com/GoogleChrome/workbox/issues/2235
   // and https://github.com/GoogleChrome/workbox/issues/2648
-  if (url && !url.startsWith('data:')) {
-    const sourcemapSrcPath = upath.resolve(upath.dirname(options.swSrc), url);
-    const sourcemapDestPath = upath.resolve(upath.dirname(options.swDest), url);
-
-    let originalMap: RawSourceMap;
-    try {
-      // readJSON returns Promise<any>.
-      // eslint-disable-next-line @typescript-eslint/no-unsafe-assignment
-      originalMap = await fse.readJSON(sourcemapSrcPath, {encoding: 'utf8'});
-    } catch (error) {
-      throw new Error(
-        `${errors['cant-find-sourcemap']} ${
-          error instanceof Error && error.message ? error.message : ''
-        }`,
-      );
-    }
+  if (srcPath && destPath) {
+    const originalMap = (await fse.readJSON(srcPath, {
+      encoding: 'utf8',
+    })) as RawSourceMap;
 
     const {map, source} = await replaceAndUpdateSourceMap({
       originalMap,
@@ -197,7 +195,7 @@ export async function injectManifest(config: unknown): Promise<BuildResult> {
     });
 
     filesToWrite[options.swDest] = source;
-    filesToWrite[sourcemapDestPath] = map;
+    filesToWrite[destPath] = map;
   } else {
     // If there's no sourcemap associated with swSrc, a simple string
     // replacement will suffice.
@@ -210,7 +208,7 @@ export async function injectManifest(config: unknown): Promise<BuildResult> {
   for (const [file, contents] of Object.entries(filesToWrite)) {
     try {
       await fse.mkdirp(upath.dirname(file));
-    } catch (error) {
+    } catch (error: unknown) {
       throw new Error(
         errors['unable-to-make-sw-directory'] +
           ` '${error instanceof Error && error.message ? error.message : ''}'`,

packages/workbox-build/src/lib/translate-url-to-sourcemap-paths.ts

@@ -0,0 +1,38 @@
+/*
+  Copyright 2021 Google LLC
+
+  Use of this source code is governed by an MIT-style
+  license that can be found in the LICENSE file or at
+  https://opensource.org/licenses/MIT.
+*/
+
+import fse from 'fs-extra';
+import upath from 'upath';
+
+import {errors} from './errors';
+
+export function translateURLToSourcemapPaths(
+  url: string,
+  swSrc: string,
+  swDest: string,
+): {
+  destPath: string | undefined;
+  srcPath: string | undefined;
+  warning: string | undefined;
+} {
+  let destPath: string | undefined = undefined;
+  let srcPath: string | undefined = undefined;
+  let warning: string | undefined = undefined;
+
+  if (url && !url.startsWith('data:')) {
+    const possibleSrcPath = upath.resolve(upath.dirname(swSrc), url);
+    if (fse.existsSync(possibleSrcPath)) {
+      srcPath = possibleSrcPath;
+      destPath = upath.resolve(upath.dirname(swDest), url);
+    } else {
+      warning = `${errors['cant-find-sourcemap']} ${possibleSrcPath}`;
+    }
+  }
+
+  return {destPath, srcPath, warning};
+}

test/workbox-build/node/inject-manifest.js

@@ -482,6 +482,28 @@ describe(`[workbox-build] inject-manifest.js (End to End)`, function () {
 
       // We can't validate the SW file contents.
     });
+
+    it(`should perform injection, but report a warning if the sourcemap file can't be found`, async function () {
+      const outputDir = tempy.directory();
+      const swSrc = upath.join(
+        SW_SRC_DIR,
+        'basic-with-invalid-sourcemap.js.nolint',
+      );
+      const swDest = upath.join(outputDir, 'basic-with-sourcemap.js');
+      const options = Object.assign({}, BASE_OPTIONS, {
+        swDest,
+        swSrc,
+      });
+
+      const {count, size, warnings} = await injectManifest(options);
+      expect(warnings.length).to.eql(1);
+      expect(warnings[0]).to.include(errors['cant-find-sourcemap']);
+      expect(count).to.eql(6);
+      // Line ending differences lead to different sizes on Windows.
+      expect(size).to.be.oneOf([2782, 2698]);
+
+      // We can't validate the SW file contents.
+    });
   });
 
   describe(`[workbox-build] removed options`, function () {

test/workbox-build/node/lib/translate-url-to-sourcemap-paths.js

@@ -0,0 +1,87 @@
+/*
+  Copyright 2018 Google LLC
+
+  Use of this source code is governed by an MIT-style
+  license that can be found in the LICENSE file or at
+  https://opensource.org/licenses/MIT.
+*/
+
+const expect = require('chai').expect;
+const proxyquire = require('proxyquire');
+
+const {errors} = require('../../../../packages/workbox-build/build/lib/errors');
+
+describe(`[workbox-build] lib/translate-url-to-sourcemap-paths.ts`, function () {
+  const MODULE_PATH =
+    '../../../../packages/workbox-build/build/lib/translate-url-to-sourcemap-paths';
+  const URL = 'sw.js.map';
+  const SWSRC = 'src/sw.js';
+  const SWDEST = 'dist/sw.js';
+
+  it(`should return undefined paths when url is undefined`, function () {
+    const {translateURLToSourcemapPaths} = require(MODULE_PATH);
+
+    const {destPath, srcPath, warning} = translateURLToSourcemapPaths(
+      undefined,
+      SWSRC,
+      SWDEST,
+    );
+
+    expect(destPath).to.be.undefined;
+    expect(srcPath).to.be.undefined;
+    expect(warning).to.be.undefined;
+  });
+
+  it(`should return undefined paths when url starts with data:`, function () {
+    const {translateURLToSourcemapPaths} = require(MODULE_PATH);
+
+    const {destPath, srcPath, warning} = translateURLToSourcemapPaths(
+      `data:${URL}`,
+      SWSRC,
+      SWDEST,
+    );
+
+    expect(destPath).to.be.undefined;
+    expect(srcPath).to.be.undefined;
+    expect(warning).to.be.undefined;
+  });
+
+  it(`should return undefined paths and a warning when the resolved URL path doesn't exist`, function () {
+    const {translateURLToSourcemapPaths} = proxyquire(MODULE_PATH, {
+      'fs-extra': {
+        existsSync: () => false,
+      },
+    });
+
+    const {destPath, srcPath, warning} = translateURLToSourcemapPaths(
+      URL,
+      SWSRC,
+      SWDEST,
+    );
+
+    expect(destPath).to.be.undefined;
+    expect(srcPath).to.be.undefined;
+    expect(warning).to.include(errors['cant-find-sourcemap']);
+  });
+
+  it(`should return valid paths and no warning when the resolved URL path exists`, function () {
+    const {translateURLToSourcemapPaths} = proxyquire(MODULE_PATH, {
+      'fs-extra': {
+        existsSync: () => true,
+      },
+      'upath': {
+        resolve: (...args) => args.join('/'),
+      },
+    });
+
+    const {destPath, srcPath, warning} = translateURLToSourcemapPaths(
+      URL,
+      SWSRC,
+      SWDEST,
+    );
+
+    expect(destPath).to.eql('dist/sw.js.map');
+    expect(srcPath).to.eq('src/sw.js.map');
+    expect(warning).to.be.undefined;
+  });
+});