Remove external config evaluation script

packages/config/package.json

@@ -32,14 +32,15 @@
     "paths"
   ],
   "dependencies": {
-    "@babel/register": "^7.8.3",
+    "@babel/core": "7.9.0",
     "@expo/babel-preset-cli": "0.2.17",
     "@expo/image-utils": "0.3.5",
     "@expo/json-file": "8.2.22",
     "@expo/plist": "0.0.9",
     "fs-extra": "9.0.0",
     "glob": "7.1.6",
     "invariant": "^2.2.4",
+    "require-from-string": "^2.0.2",
     "resolve-from": "^5.0.0",
     "semver": "^7.1.3",
     "slugify": "^1.3.4",

packages/config/src/__tests__/getConfig-test.js

@@ -37,14 +37,6 @@ describe('modifyConfigAsync', () => {
 });
 
 describe('getDynamicConfig', () => {
-  // This tests error are thrown properly and ensures that a more specific
-  // config is used instead of defaulting to a valid substitution.
-  it(`throws a useful error for dynamic configs with a syntax error`, () => {
-    const paths = getConfigFilePaths(join(__dirname, 'fixtures/behavior/syntax-error'));
-    expect(() => getDynamicConfig(paths.dynamicConfigPath, {})).toThrowError(
-      'Unexpected token (3:4)'
-    );
-  });
   it(`exports a function`, () => {
     expect(
       getDynamicConfig(
@@ -62,6 +54,15 @@ describe('getDynamicConfig', () => {
     ).toBe('object');
   });
 
+  // This tests error are thrown properly and ensures that a more specific
+  // config is used instead of defaulting to a valid substitution.
+  it(`throws a useful error for dynamic configs with a syntax error`, () => {
+    const paths = getConfigFilePaths(join(__dirname, 'fixtures/behavior/syntax-error'));
+    expect(() => getDynamicConfig(paths.dynamicConfigPath, {})).toThrowError(
+      'Unexpected token (3:4)'
+    );
+  });
+
   describe('process.cwd in a child process', () => {
     const originalCwd = process.cwd();
     const projectRoot = join(__dirname, 'fixtures/behavior/dynamic-cwd');
@@ -74,15 +75,16 @@ describe('getDynamicConfig', () => {
       process.chdir(originalCwd);
     });
 
+    // Test that hot evaluation is spawned in the expected location
+    // https://github.com/expo/expo-cli/pull/2220
     it('process.cwd in read-config script is not equal to the project root', () => {
       const { config } = getDynamicConfig(join(projectRoot, 'app.config.ts'), {});
       expect(config.processCwd).toBe(__dirname);
-    });
-    it('process.cwd in read-config script is equal to the project root', () => {
-      const { config } = getDynamicConfig(join(projectRoot, 'app.config.ts'), {
-        projectRoot,
-      });
-      expect(config.processCwd).toBe(projectRoot);
+      expect(
+        getDynamicConfig(join(projectRoot, 'app.config.ts'), {
+          projectRoot,
+        }).config.processCwd
+      ).toBe(__dirname);
     });
   });
 });

packages/config/src/evalConfig.ts

@@ -0,0 +1,48 @@
+// @ts-ignore
+import requireString from 'require-from-string';
+
+import { AppJSONConfig, ConfigContext, ExpoConfig } from './Config.types';
+import { ConfigError } from './Errors';
+import { serializeAndEvaluate } from './Serialize';
+// import babel from '@babel/core';
+
+type RawDynamicConfig = AppJSONConfig | Partial<ExpoConfig> | null;
+
+export type DynamicConfigResults = { config: RawDynamicConfig; exportedObjectType: string };
+
+/**
+ * Transpile and evaluate the dynamic config object.
+ * This method is shared between the standard reading method in getConfig, and the headless script.
+ *
+ * @param options configFile path to the dynamic app.config.*, request to send to the dynamic config if it exports a function.
+ * @returns the serialized and evaluated config along with the exported object type (object or function).
+ */
+export function evalConfig(
+  configFile: string,
+  request: ConfigContext | null
+): DynamicConfigResults {
+  const babel = require('@babel/core');
+  const { code } = babel.transformFileSync(require.resolve(configFile), {
+    only: [configFile],
+    cwd: request?.projectRoot || process.cwd(),
+    babelrc: false,
+    ignore: [/node_modules/],
+    filename: 'unknown',
+    presets: [require.resolve('@expo/babel-preset-cli')],
+  });
+
+  let result = requireString(code);
+  if (result.default != null) {
+    result = result.default;
+  }
+  const exportedObjectType = typeof result;
+  if (typeof result === 'function') {
+    result = result(request);
+  }
+
+  if (result instanceof Promise) {
+    throw new ConfigError(`Config file ${configFile} cannot return a Promise.`, 'INVALID_CONFIG');
+  }
+
+  return { config: serializeAndEvaluate(result), exportedObjectType };
+}

packages/config/src/getConfig.ts

@@ -1,30 +1,25 @@
 import JsonFile from '@expo/json-file';
-import { spawnSync } from 'child_process';
 
 import { AppJSONConfig, ConfigContext, ExpoConfig } from './Config.types';
-import { ConfigError, errorFromJSON } from './Errors';
-import { fileExists } from './Modules';
-import { serializeAndEvaluate } from './Serialize';
-
-type RawDynamicConfig = AppJSONConfig | Partial<ExpoConfig> | null;
-
-type DynamicConfigResults = { config: RawDynamicConfig; exportedObjectType: string };
+import { ConfigError } from './Errors';
+import { DynamicConfigResults, evalConfig } from './evalConfig';
 
 function isMissingFileCode(code: string): boolean {
   return ['ENOENT', 'MODULE_NOT_FOUND', 'ENOTDIR'].includes(code);
 }
 
-function readConfigFile(
-  configFilePath: string,
-  context: ConfigContext
-): null | DynamicConfigResults {
-  if (!fileExists(configFilePath)) return null;
-
+// We cannot use async config resolution right now because Next.js doesn't support async configs.
+// If they don't add support for async Webpack configs then we may need to pull support for Next.js.
+function readConfigFile(configFile: string, context: ConfigContext): null | DynamicConfigResults {
   try {
-    return evalConfig(configFilePath, context);
+    return evalConfig(configFile, context);
   } catch (error) {
     // If the file doesn't exist then we should skip it and continue searching.
     if (!isMissingFileCode(error.code)) {
+      // @ts-ignore
+      error.isConfigError = true;
+      // @ts-ignore: Replace the babel stack with a more relevant stack.
+      error.stack = new Error().stack;
       throw error;
     }
   }
@@ -34,48 +29,18 @@ function readConfigFile(
 export function getDynamicConfig(configPath: string, request: ConfigContext): DynamicConfigResults {
   const config = readConfigFile(configPath, request);
   if (config) {
-    return serializeAndEvaluate(config);
+    // The config must be serialized and evaluated ahead of time so the spawned process can send it over.
+    return config;
   }
+  // TODO: It seems this is only thrown if the file cannot be found (which may never happen).
+  // If so we should throw a more helpful error.
   throw new ConfigError(`Failed to read config at: ${configPath}`, 'INVALID_CONFIG');
 }
 
-export function getStaticConfig(configPath: string): AppJSONConfig | ExpoConfig | null {
+export function getStaticConfig(configPath: string): AppJSONConfig | ExpoConfig {
   const config = JsonFile.read(configPath, { json5: true });
   if (config) {
-    return serializeAndEvaluate(config);
+    return config as any;
   }
   throw new ConfigError(`Failed to read config at: ${configPath}`, 'INVALID_CONFIG');
 }
-
-// We cannot use async config resolution right now because Next.js doesn't support async configs.
-// If they don't add support for async Webpack configs then we may need to pull support for Next.js.
-function evalConfig(configFile: string, request: ConfigContext): DynamicConfigResults {
-  const spawnResults = spawnSync(
-    'node',
-    [
-      require.resolve('@expo/config/build/scripts/read-config.js'),
-      '--colors',
-      configFile,
-      JSON.stringify({ ...request, config: serializeAndEvaluate(request.config) }),
-    ],
-    { cwd: request.projectRoot || process.cwd() }
-  );
-
-  if (spawnResults.status === 0) {
-    const spawnResultString = spawnResults.stdout.toString('utf8').trim();
-    const logs = spawnResultString.split('\n');
-    // Get the last console log to prevent parsing anything logged in the config.
-    const lastLog = logs.pop()!;
-    for (const log of logs) {
-      // Log out the logs from the config
-      console.log(log);
-    }
-    // Parse the final log of the script, it's the serialized config and exported object type.
-    const results = JSON.parse(lastLog);
-    return results;
-  } else {
-    // Parse the error data and throw it as expected
-    const errorData = JSON.parse(spawnResults.stderr.toString('utf8'));
-    throw errorFromJSON(errorData);
-  }
-}

yarn.lock

@@ -1129,7 +1129,7 @@
     "@babel/helper-plugin-utils" "^7.0.0"
     "@babel/plugin-transform-typescript" "^7.7.4"
 
-"@babel/register@^7.0.0", "@babel/register@^7.8.3":
+"@babel/register@7.8.3", "@babel/register@^7.0.0":
   version "7.8.3"
   resolved "https://registry.yarnpkg.com/@babel/register/-/register-7.8.3.tgz#5d5d30cfcc918437535d724b8ac1e4a60c5db1f8"
   integrity sha512-t7UqebaWwo9nXWClIPLPloa5pN33A2leVs8Hf0e9g9YwUP8/H9NeR7DJU+4CXo23QtjChQv5a3DjEtT83ih1rg==
@@ -18653,6 +18653,11 @@ require-directory@^2.1.1:
   resolved "https://registry.yarnpkg.com/require-directory/-/require-directory-2.1.1.tgz#8c64ad5fd30dab1c976e2344ffe7f792a6a6df42"
   integrity sha1-jGStX9MNqxyXbiNE/+f3kqam30I=
 
+require-from-string@^2.0.2:
+  version "2.0.2"
+  resolved "https://registry.yarnpkg.com/require-from-string/-/require-from-string-2.0.2.tgz#89a7fdd938261267318eafe14f9c32e598c36909"
+  integrity sha512-Xf0nWe6RseziFMu+Ap9biiUbmplq6S9/p+7w7YXP/JBHhrUDDUhwa+vANyubuqfZWTveU//DYVGsDG7RKL/vEw==
+
 require-main-filename@^1.0.1:
   version "1.0.1"
   resolved "https://registry.yarnpkg.com/require-main-filename/-/require-main-filename-1.0.1.tgz#97f717b69d48784f5f526a6c5aa8ffdda055a4d1"