error plugin import from outside

Summary:
Plugins can not require files outside their folder, to make sure they don't pull in any dependencies from Flipper which are not exported by the main app.

However, those imports simply resolve to `undefined`. This diff adds a check in the babel-transform for plugins and throws an error if something from outside the plugin is required.

Reviewed By: passy

Differential Revision: D10297980

fbshipit-source-id: 1606f3211103281f9f4aa7bb2f3ca4d085d0ea1b

static/transforms/__tests__/flipper-requires.node.js

@@ -0,0 +1,70 @@
+/**
+ * Copyright 2018-present Facebook.
+ * This source code is licensed under the MIT license found in the
+ * LICENSE file in the root directory of this source tree.
+ * @format
+ */
+
+import {parse} from '@babel/parser';
+import {transformFromAstSync} from '@babel/core';
+import generate from '@babel/generator';
+
+import flipperRequires from '../flipper-requires';
+
+const babelOptions = {
+  ast: true,
+  plugins: [flipperRequires],
+  filename: 'index.js',
+};
+
+test('transform react requires to global window', () => {
+  const src = 'require("react")';
+  const ast = parse(src);
+  const transformed = transformFromAstSync(ast, src, babelOptions).ast;
+  const {code} = generate(transformed);
+  expect(code).toBe('window.React;');
+});
+
+test('transform react-dom requires to global window', () => {
+  const src = 'require("react-dom")';
+  const ast = parse(src);
+  const transformed = transformFromAstSync(ast, src, babelOptions).ast;
+  const {code} = generate(transformed);
+  expect(code).toBe('window.ReactDOM;');
+});
+
+test('transform flipper requires to global window', () => {
+  const src = 'require("flipper")';
+  const ast = parse(src);
+  const transformed = transformFromAstSync(ast, src, babelOptions).ast;
+  const {code} = generate(transformed);
+  expect(code).toBe('window.Flipper;');
+});
+
+test('transform React identifier to window.React', () => {
+  const src = 'React;';
+  const ast = parse(src);
+  const transformed = transformFromAstSync(ast, src, babelOptions).ast;
+  const {code} = generate(transformed);
+  expect(code).toBe('window.React;');
+});
+
+test('throw error when requiring outside the plugin', () => {
+  const src = 'require("../test.js")';
+  const ast = parse(src);
+  expect(() => {
+    transformFromAstSync(ast, src, babelOptions);
+  }).toThrow();
+});
+
+test('allow requiring from parent folder as long as we stay in plugin folder', () => {
+  const src = 'require("../test.js")';
+  const ast = parse(src);
+  const transformed = transformFromAstSync(ast, src, {
+    ...babelOptions,
+    root: '/path/to/plugin',
+    filename: '/path/to/plugin/subfolder/index.js',
+  }).ast;
+  const {code} = generate(transformed);
+  expect(code).toBe('require("../test.js");');
+});