fix(lambda-nodejs): parcel build cannot find target (#8838)

The `PackageJsonManager` was always targeting the `package.json` of
`@aws-cdk/aws-lambda-nodejs` and not the one closest to the entry file.

This was not detected in the tests inside the repo because both files
are the same.

Closes #8837


----

*By submitting this pull request, I confirm that my contribution is made under the terms of the Apache-2.0 license*

packages/@aws-cdk/aws-lambda-nodejs/lib/bundling.ts

@@ -3,7 +3,7 @@ import * as cdk from '@aws-cdk/core';
 import * as fs from 'fs';
 import * as path from 'path';
 import { PackageJsonManager } from './package-json-manager';
-import { findClosestPathContaining } from './util';
+import { findUp } from './util';
 
 /**
  * Base options for Parcel bundling
@@ -97,7 +97,7 @@ export class Bundling {
    */
   public static parcel(options: ParcelOptions): lambda.AssetCode {
     // Find project root
-    const projectRoot = options.projectRoot ?? findClosestPathContaining(`.git${path.sep}`);
+    const projectRoot = options.projectRoot ?? findUp(`.git${path.sep}`);
     if (!projectRoot) {
       throw new Error('Cannot find project root. Please specify it with `projectRoot`.');
     }
@@ -110,7 +110,7 @@ export class Bundling {
       },
     });
 
-    const packageJsonManager = new PackageJsonManager();
+    const packageJsonManager = new PackageJsonManager(path.dirname(options.entry));
 
     // Collect external and install modules
     let includeNodeModules: { [key: string]: boolean } | undefined;

packages/@aws-cdk/aws-lambda-nodejs/lib/function.ts

@@ -54,8 +54,9 @@ export class NodejsFunction extends lambda.Function {
       : lambda.Runtime.NODEJS_10_X;
     const runtime = props.runtime ?? defaultRunTime;
 
-    // We need to restore the package.json after bundling
-    const packageJsonManager = new PackageJsonManager();
+    // Look for the closest package.json starting in the directory of the entry
+    // file. We need to restore it after bundling.
+    const packageJsonManager = new PackageJsonManager(path.dirname(entry));
 
     try {
       super(scope, id, {

packages/@aws-cdk/aws-lambda-nodejs/lib/package-json-manager.ts

@@ -1,6 +1,6 @@
 import * as fs from 'fs';
 import * as path from 'path';
-import { findClosestPathContaining } from './util';
+import { findUp } from './util';
 
 /**
  * A package.json manager to act on the closest package.json file.
@@ -13,8 +13,8 @@ export class PackageJsonManager {
   private readonly pkg: Buffer;
   private readonly pkgJson: PackageJson;
 
-  constructor() {
-    const pkgPath = findClosestPathContaining('package.json');
+  constructor(directory: string) {
+    const pkgPath = findUp('package.json', directory);
     if (!pkgPath) {
       throw new Error('Cannot find a `package.json` in this project.');
     }

packages/@aws-cdk/aws-lambda-nodejs/lib/util.ts

@@ -51,14 +51,15 @@ export function nodeMajorVersion(): number {
 }
 
 /**
- * Finds the closest path containg a path
+ * Find a file by walking up parent directories
  */
-export function findClosestPathContaining(p: string): string | undefined {
-  for (const nodeModulesPath of module.paths) {
-    if (fs.existsSync(path.join(path.dirname(nodeModulesPath), p))) {
-      return path.dirname(nodeModulesPath);
-    }
+export function findUp(name: string, directory: string = process.cwd()): string | undefined {
+  const { root } = path.parse(directory);
+  if (directory === root && !fs.existsSync(path.join(directory, name))) {
+    return undefined;
   }
-
-  return undefined;
+  if (fs.existsSync(path.join(directory, name))) {
+    return directory;
+  }
+  return findUp(name, path.dirname(directory));
 }

packages/@aws-cdk/aws-lambda-nodejs/test/bundling.test.ts

@@ -3,12 +3,21 @@ import { Code, Runtime } from '@aws-cdk/aws-lambda';
 import { AssetHashType } from '@aws-cdk/core';
 import { version as delayVersion } from 'delay/package.json';
 import * as fs from 'fs';
+import * as path from 'path';
 import { Bundling } from '../lib/bundling';
+import * as util from '../lib/util';
 
 jest.mock('@aws-cdk/aws-lambda');
 const writeFileSyncMock = jest.spyOn(fs, 'writeFileSync').mockReturnValue();
 const existsSyncOriginal = fs.existsSync;
 const existsSyncMock = jest.spyOn(fs, 'existsSync');
+const originalFindUp = util.findUp;
+const findUpMock = jest.spyOn(util, 'findUp').mockImplementation((name: string, directory) => {
+  if (name === 'package.json') {
+    return path.join(__dirname, '..');
+  }
+  return originalFindUp(name, directory);
+});
 
 beforeEach(() => {
   jest.clearAllMocks();
@@ -59,6 +68,9 @@ test('Parcel bundling', () => {
       },
     },
   }));
+
+  // Searches for the package.json starting in the directory of the entry file
+  expect(findUpMock).toHaveBeenCalledWith('package.json', '/project/folder');
 });
 
 test('Parcel with Windows paths', () => {

packages/@aws-cdk/aws-lambda-nodejs/test/util.test.ts

@@ -0,0 +1,13 @@
+import * as path from 'path';
+import { findUp } from '../lib/util';
+
+test('findUp', () => {
+  // Starting at process.cwd()
+  expect(findUp('README.md')).toMatch(/aws-lambda-nodejs$/);
+
+  // Non existing file
+  expect(findUp('non-existing-file.unknown')).toBe(undefined);
+
+  // Starting at a specific path
+  expect(findUp('util.test.ts', path.join(__dirname, 'integ-handlers'))).toMatch(/aws-lambda-nodejs\/test$/);
+});