Resolve Babel options ahead of time 🎉 (#1262)

* package-hash@^2

* Allow precompiler setup to be asynchronous

* Consistently refer to babel-config module as babelConfigHelper

* Manage Babel config using hullabaloo

Fixes #707

* Disable Babel cache when precompiling

api.js

@@ -12,6 +12,7 @@ const Promise = require('bluebird');
 const getPort = require('get-port');
 const arrify = require('arrify');
 const ms = require('ms');
+const babelConfigHelper = require('./lib/babel-config');
 const CachingPrecompiler = require('./lib/caching-precompiler');
 const RunStatus = require('./lib/run-status');
 const AvaError = require('./lib/ava-error');
@@ -105,11 +106,14 @@ class Api extends EventEmitter {
 		this.options.cacheDir = cacheDir;
 
 		const isPowerAssertEnabled = this.options.powerAssert !== false;
-		this.precompiler = new CachingPrecompiler({
-			path: cacheDir,
-			babel: this.options.babelConfig,
-			powerAssert: isPowerAssertEnabled
-		});
+		return babelConfigHelper.build(this.options.projectDir, cacheDir, this.options.babelConfig, isPowerAssertEnabled)
+			.then(result => {
+				this.precompiler = new CachingPrecompiler({
+					path: cacheDir,
+					getBabelOptions: result.getOptions,
+					babelCacheKeys: result.cacheKeys
+				});
+			});
 	}
 	_precompileHelpers() {
 		this._precompiledHelpers = {};
@@ -144,9 +148,8 @@ class Api extends EventEmitter {
 			return Promise.resolve(runStatus);
 		}
 
-		this._setupPrecompiler(files);
-
-		return this._precompileHelpers()
+		return this._setupPrecompiler(files)
+			.then(() => this._precompileHelpers())
 			.then(() => {
 				if (this.options.timeout) {
 					this._setupTimeout(runStatus);

docs/recipes/babelrc.md

@@ -69,6 +69,8 @@ Using the `"inherit"` shortcut will cause your tests to be transpiled the same a
 
 In the above example, both tests and sources will be transpiled using the [`@ava/stage-4`](https://github.com/avajs/babel-preset-stage-4) and [`react`](http://babeljs.io/docs/plugins/preset-react/) presets.
 
+AVA will only look for a `.babelrc` file in the same directory as the `package.json` file. If not found then it assumes your Babel config lives in the `package.json` file.
+
 ## Extend your source transpilation configuration
 
 When specifying the Babel config for your tests, you can set the `babelrc` option to `true`. This will merge the specified plugins with those from your [`babelrc`](http://babeljs.io/docs/usage/babelrc/).
@@ -93,6 +95,8 @@ When specifying the Babel config for your tests, you can set the `babelrc` optio
 
 In the above example, *sources* are compiled use [`@ava/stage-4`](https://github.com/avajs/babel-preset-stage-4) and [`react`](http://babeljs.io/docs/plugins/preset-react/), *tests* use those same plugins, plus the additional `custom` plugins specified.
 
+AVA will only look for a `.babelrc` file in the same directory as the `package.json` file. If not found then it assumes your Babel config lives in the `package.json` file.
+
 ## Extend an alternate config file.
 
 

lib/babel-config.js

@@ -1,8 +1,11 @@
 'use strict';
+const fs = require('fs');
 const path = require('path');
 const chalk = require('chalk');
 const figures = require('figures');
-const convertSourceMap = require('convert-source-map');
+const configManager = require('hullabaloo-config-manager');
+const md5Hex = require('md5-hex');
+const mkdirp = require('mkdirp');
 const colors = require('./colors');
 
 function validate(conf) {
@@ -24,85 +27,122 @@ function validate(conf) {
 	return conf;
 }
 
-function lazy(buildPreset) {
-	let preset;
-
-	return babel => {
-		if (!preset) {
-			preset = buildPreset(babel);
+const SOURCE = '(AVA) Base Babel config';
+const AVA_DIR = path.join(__dirname, '..');
+
+function verifyExistingOptions(verifierFile, baseConfig, cache) {
+	return new Promise((resolve, reject) => {
+		try {
+			resolve(fs.readFileSync(verifierFile));
+		} catch (err) {
+			if (err && err.code === 'ENOENT') {
+				resolve(null);
+			} else {
+				reject(err);
+			}
 		}
-
-		return preset;
-	};
+	})
+		.then(buffer => {
+			if (!buffer) {
+				return null;
+			}
+
+			const verifier = configManager.restoreVerifier(buffer);
+			const fixedSourceHashes = new Map();
+			fixedSourceHashes.set(baseConfig.source, baseConfig.hash);
+			if (baseConfig.extends) {
+				fixedSourceHashes.set(baseConfig.extends.source, baseConfig.extends.hash);
+			}
+			return verifier.verifyCurrentEnv({sources: fixedSourceHashes}, cache)
+				.then(result => {
+					if (!result.cacheKeys) {
+						return null;
+					}
+
+					if (result.dependenciesChanged) {
+						fs.writeFileSync(verifierFile, result.verifier.toBuffer());
+					}
+
+					return result.cacheKeys;
+				});
+		});
 }
 
-const stage4 = lazy(() => require('@ava/babel-preset-stage-4')());
-
-function makeTransformTestFiles(powerAssert) {
-	return lazy(babel => {
-		return require('@ava/babel-preset-transform-test-files')(babel, {powerAssert});
-	});
+function resolveOptions(baseConfig, cache, optionsFile, verifierFile) {
+	return configManager.fromConfig(baseConfig, {cache})
+		.then(result => {
+			fs.writeFileSync(optionsFile, result.generateModule());
+
+			return result.createVerifier()
+				.then(verifier => {
+					fs.writeFileSync(verifierFile, verifier.toBuffer());
+					return verifier.cacheKeysForCurrentEnv();
+				});
+		});
 }
 
-function build(babelConfig, powerAssert, filePath, code) {
-	babelConfig = validate(babelConfig);
-
-	let options;
-
-	if (babelConfig === 'default') {
-		options = {
-			babelrc: false,
-			presets: [stage4]
-		};
-	} else if (babelConfig === 'inherit') {
-		options = {
-			babelrc: true
-		};
-	} else {
-		options = {
-			babelrc: false
-		};
-
-		Object.assign(options, babelConfig);
+function build(projectDir, cacheDir, userOptions, powerAssert) {
+	// Compute a seed based on the Node.js version and the project directory.
+	// Dependency hashes may vary based on the Node.js version, e.g. with the
+	// @ava/stage-4 Babel preset. Sources and dependencies paths are  absolute in
+	// the generated module and verifier state. Those paths wouldn't necessarily
+	// be valid if the project directory changes.
+	const seed = md5Hex([process.versions.node, projectDir]);
+
+	// Ensure cacheDir exists
+	mkdirp.sync(cacheDir);
+
+	// The file names predict where valid options may be cached, and thus should
+	// include the seed.
+	const optionsFile = path.join(cacheDir, `${seed}.babel-options.js`);
+	const verifierFile = path.join(cacheDir, `${seed}.verifier.bin`);
+
+	const baseOptions = {
+		babelrc: false,
+		presets: [
+			['@ava/transform-test-files', {powerAssert}]
+		]
+	};
+	if (userOptions === 'default') {
+		baseOptions.presets.unshift('@ava/stage-4');
 	}
 
-	const sourceMap = getSourceMap(filePath, code);
-
-	Object.assign(options, {
-		inputSourceMap: sourceMap,
-		filename: filePath,
-		sourceMaps: true,
-		ast: false
+	const baseConfig = configManager.createConfig({
+		dir: AVA_DIR, // Presets are resolved relative to this directory
+		hash: md5Hex(JSON.stringify(baseOptions)),
+		json5: false,
+		options: baseOptions,
+		source: SOURCE
 	});
 
-	if (!options.presets) {
-		options.presets = [];
-	}
-	options.presets.push(makeTransformTestFiles(powerAssert));
-
-	return options;
-}
-
-function getSourceMap(filePath, code) {
-	let sourceMap = convertSourceMap.fromSource(code);
-
-	if (!sourceMap) {
-		const dirPath = path.dirname(filePath);
-		sourceMap = convertSourceMap.fromMapFileSource(code, dirPath);
-	}
-
-	if (sourceMap) {
-		sourceMap = sourceMap.toObject();
+	if (userOptions !== 'default') {
+		baseConfig.extend(configManager.createConfig({
+			dir: projectDir,
+			options: userOptions === 'inherit' ?
+				{babelrc: true} :
+				userOptions,
+			source: path.join(projectDir, 'package.json') + '#ava.babel',
+			hash: md5Hex(JSON.stringify(userOptions))
+		}));
 	}
 
-	return sourceMap;
+	const cache = configManager.prepareCache();
+	return verifyExistingOptions(verifierFile, baseConfig, cache)
+		.then(cacheKeys => {
+			if (cacheKeys) {
+				return cacheKeys;
+			}
+
+			return resolveOptions(baseConfig, cache, optionsFile, verifierFile);
+		})
+		.then(cacheKeys => ({
+			getOptions: require(optionsFile).getOptions, // eslint-disable-line import/no-dynamic-require
+			// Include the seed in the cache keys used to store compilation results.
+			cacheKeys: Object.assign({seed}, cacheKeys)
+		}));
 }
 
 module.exports = {
 	validate,
-	build,
-	presetHashes: [
-		require('@ava/babel-preset-stage-4/package-hash'),
-		require('@ava/babel-preset-transform-test-files/package-hash')
-	]
+	build
 };

lib/caching-precompiler.js

@@ -7,17 +7,29 @@ const packageHash = require('package-hash');
 const stripBomBuf = require('strip-bom-buf');
 const autoBind = require('auto-bind');
 const md5Hex = require('md5-hex');
-const babelConfigHelper = require('./babel-config');
+
+function getSourceMap(filePath, code) {
+	let sourceMap = convertSourceMap.fromSource(code);
+
+	if (!sourceMap) {
+		const dirPath = path.dirname(filePath);
+		sourceMap = convertSourceMap.fromMapFileSource(code, dirPath);
+	}
+
+	if (sourceMap) {
+		sourceMap = sourceMap.toObject();
+	}
+
+	return sourceMap;
+}
 
 class CachingPrecompiler {
 	constructor(options) {
 		autoBind(this);
 
-		options = options || {};
-
-		this.babelConfig = babelConfigHelper.validate(options.babel);
+		this.getBabelOptions = options.getBabelOptions;
+		this.babelCacheKeys = options.babelCacheKeys;
 		this.cacheDirPath = options.path;
-		this.powerAssert = Boolean(options.powerAssert);
 		this.fileHashes = {};
 		this.transform = this._createTransform();
 	}
@@ -37,8 +49,23 @@ class CachingPrecompiler {
 	_transform(code, filePath, hash) {
 		code = code.toString();
 
-		const options = babelConfigHelper.build(this.babelConfig, this.powerAssert, filePath, code);
-		const result = this.babel.transform(code, options);
+		let result;
+		const originalBabelDisableCache = process.env.BABEL_DISABLE_CACHE;
+		try {
+			// Disable Babel's cache. AVA has good cache management already.
+			process.env.BABEL_DISABLE_CACHE = '1';
+
+			result = this.babel.transform(code, Object.assign(this.getBabelOptions(), {
+				inputSourceMap: getSourceMap(filePath, code),
+				filename: filePath,
+				sourceMaps: true,
+				ast: false
+			}));
+		} finally {
+			// Restore the original value. It is passed to workers, where users may
+			// not want Babel's cache to be disabled.
+			process.env.BABEL_DISABLE_CACHE = originalBabelDisableCache;
+		}
 
 		// Save source map
 		const mapPath = path.join(this.cacheDirPath, `${hash}.js.map`);
@@ -56,12 +83,7 @@ class CachingPrecompiler {
 		const salt = packageHash.sync([
 			require.resolve('../package.json'),
 			require.resolve('babel-core/package.json')
-		], {
-			babelConfig: this.babelConfig,
-			majorNodeVersion: process.version.split('.')[0],
-			powerAssert: this.powerAssert,
-			presetHashes: babelConfigHelper.presetHashes
-		});
+		], this.babelCacheKeys);
 
 		return cachingTransform({
 			factory: this._init,

lib/cli.js

@@ -15,7 +15,7 @@ const MiniReporter = require('./reporters/mini');
 const TapReporter = require('./reporters/tap');
 const Logger = require('./logger');
 const Watcher = require('./watcher');
-const babelConfig = require('./babel-config');
+const babelConfigHelper = require('./babel-config');
 
 // Bluebird specific
 Promise.longStackTraces();
@@ -115,7 +115,7 @@ exports.run = () => {
 		powerAssert: cli.flags.powerAssert !== false,
 		explicitTitles: cli.flags.watch,
 		match: arrify(cli.flags.match),
-		babelConfig: babelConfig.validate(conf.babel),
+		babelConfig: babelConfigHelper.validate(conf.babel),
 		resolveTestsFrom: cli.input.length === 0 ? projectDir : process.cwd(),
 		projectDir,
 		timeout: cli.flags.timeout,

package.json

@@ -125,6 +125,7 @@
     "get-port": "^2.1.0",
     "globby": "^6.0.0",
     "has-flag": "^2.0.0",
+    "hullabaloo-config-manager": "^0.2.0",
     "ignore-by-default": "^1.0.0",
     "indent-string": "^3.0.0",
     "is-ci": "^1.0.7",
@@ -143,11 +144,12 @@
     "max-timeout": "^1.0.0",
     "md5-hex": "^2.0.0",
     "meow": "^3.7.0",
+    "mkdirp": "^0.5.1",
     "ms": "^0.7.1",
     "multimatch": "^2.1.0",
     "observable-to-promise": "^0.4.0",
     "option-chain": "^0.1.0",
-    "package-hash": "^1.2.0",
+    "package-hash": "^2.0.0",
     "pkg-conf": "^2.0.0",
     "plur": "^2.0.0",
     "pretty-ms": "^2.0.0",
@@ -175,7 +177,6 @@
     "inquirer": "^2.0.0",
     "is-array-sorted": "^1.0.0",
     "lolex": "^1.4.0",
-    "mkdirp": "^0.5.1",
     "nyc": "^10.0.0",
     "pify": "^2.3.0",
     "proxyquire": "^1.7.4",