wp-env: Set core source to latest when null (#43133)

* Set core source to latest if config.core is null to fix a crash

* Cache WordPress version to avoid extra network requests

packages/env/CHANGELOG.md

@@ -2,13 +2,16 @@
 
 ## Unreleased
 
+### Bug Fix
+-   Fix a crash when "core" was set to `null` in a `.wp-env.json` file. We now use the latest stable WordPress version in that case. This also restores the previous behavior of `"core": null` in `.wp-env.override.json`, which was to use the latest stable WordPress version.
+
 ## 5.1.0 (2022-08-10)
 
 ### Enhancement
-- Previously, wp-env used the WordPress version provided by Docker in the WordPress image for installations which don't specify a WordPress version. Now, wp-env will find the latest stable version on WordPress.org and check out the https://github.com/WordPress/WordPress repository at the tag matching that version. In most cases, this will match what Docker provides. The benefit is that wp-env (and WordPress.org) now controls the default WordPress version rather than Docker.
+-   Previously, wp-env used the WordPress version provided by Docker in the WordPress image for installations which don't specify a WordPress version. Now, wp-env will find the latest stable version on WordPress.org and check out the https://github.com/WordPress/WordPress repository at the tag matching that version. In most cases, this will match what Docker provides. The benefit is that wp-env (and WordPress.org) now controls the default WordPress version rather than Docker.
 
 ### Bug Fix
-- Downloading a default WordPress version also resolves a bug where the wrong WordPress test files were used if no core source was specified in wp-env.json. The current trunk test files were downloaded rather than the stable version. Now, the test files will match the default stable version.
+-   Downloading a default WordPress version also resolves a bug where the wrong WordPress test files were used if no core source was specified in wp-env.json. The current trunk test files were downloaded rather than the stable version. Now, the test files will match the default stable version.
 
 ## 5.0.0 (2022-07-27)
 

packages/env/lib/config/config.js

@@ -15,7 +15,6 @@ const readRawConfigFile = require( './read-raw-config-file' );
 const parseConfig = require( './parse-config' );
 const { includeTestsPath, parseSourceString } = parseConfig;
 const md5 = require( '../md5' );
-const { getLatestWordPressVersion } = require( '../wordpress' );
 
 /**
  * wp-env configuration.
@@ -85,21 +84,9 @@ module.exports = async function readConfig( configPath ) {
 	const detectedLocalConfig =
 		Object.keys( { ...baseConfig, ...overrideConfig } ).length > 0;
 
-	// If there is no local WordPress version, use the latest stable version from GitHub.
-	let coreRef;
-	if ( ! overrideConfig.core && ! baseConfig.core ) {
-		const wpVersion = await getLatestWordPressVersion();
-		if ( ! wpVersion ) {
-			throw new ValidationError(
-				'Could not find the latest WordPress version. There may be a network issue.'
-			);
-		}
-		coreRef = `WordPress/WordPress#${ wpVersion }`;
-	}
-
 	// Default configuration which is overridden by .wp-env.json files.
 	const defaultConfiguration = {
-		core: coreRef,
+		core: null, // Indicates that the latest stable version should ultimately be used.
 		phpVersion: null,
 		plugins: [],
 		themes: [],
@@ -155,23 +142,21 @@ module.exports = async function readConfig( configPath ) {
 
 	// Merge each of the specified environment-level overrides.
 	const allPorts = new Set(); // Keep track of unique ports for validation.
-	const env = allEnvs.reduce( ( result, environment ) => {
-		result[ environment ] = parseConfig(
+	const env = {};
+	for ( const envName of allEnvs ) {
+		env[ envName ] = await parseConfig(
 			validateConfig(
 				mergeWpServiceConfigs( [
-					...getEnvConfig( defaultConfiguration, environment ),
-					...getEnvConfig( baseConfig, environment ),
-					...getEnvConfig( overrideConfig, environment ),
+					...getEnvConfig( defaultConfiguration, envName ),
+					...getEnvConfig( baseConfig, envName ),
+					...getEnvConfig( overrideConfig, envName ),
 				] ),
-				environment
+				envName
 			),
-			{
-				workDirectoryPath,
-			}
+			{ workDirectoryPath }
 		);
-		allPorts.add( result[ environment ].port );
-		return result;
-	}, {} );
+		allPorts.add( env[ envName ].port );
+	}
 
 	if ( allPorts.size !== allEnvs.length ) {
 		throw new ValidationError(
@@ -262,6 +247,7 @@ async function getDefaultBaseConfig( configPath ) {
  * @return {WPConfig} configuration object with overrides applied.
  */
 function withOverrides( config ) {
+	const workDirectoryPath = config.workDirectoryPath;
 	// Override port numbers with environment variables.
 	config.env.development.port =
 		getNumberFromEnvVariable( 'WP_ENV_PORT' ) ||
@@ -273,10 +259,8 @@ function withOverrides( config ) {
 	// Override WordPress core with environment variable.
 	if ( process.env.WP_ENV_CORE ) {
 		const coreSource = includeTestsPath(
-			parseSourceString( process.env.WP_ENV_CORE, {
-				workDirectoryPath: config.workDirectoryPath,
-			} ),
-			{ workDirectoryPath: config.workDirectoryPath }
+			parseSourceString( process.env.WP_ENV_CORE, { workDirectoryPath } ),
+			{ workDirectoryPath }
 		);
 		config.env.development.coreSource = coreSource;
 		config.env.tests.coreSource = coreSource;

packages/env/lib/config/parse-config.js

@@ -9,6 +9,7 @@ const os = require( 'os' );
  * Internal dependencies
  */
 const { ValidationError } = require( './validate-config' );
+const { getLatestWordPressVersion } = require( '../wordpress' );
 
 /**
  * @typedef {import('./config').WPServiceConfig} WPServiceConfig
@@ -32,12 +33,12 @@ const HOME_PATH_PREFIX = `~${ path.sep }`;
  * @param {string} options.workDirectoryPath Path to the work directory located in ~/.wp-env.
  * @return {WPServiceConfig} Parsed environment-level configuration.
  */
-module.exports = function parseConfig( config, options ) {
+module.exports = async function parseConfig( config, options ) {
 	return {
 		port: config.port,
 		phpVersion: config.phpVersion,
 		coreSource: includeTestsPath(
-			parseSourceString( config.core, options ),
+			await parseCoreSource( config.core, options ),
 			options
 		),
 		pluginSources: config.plugins.map( ( sourceString ) =>
@@ -58,6 +59,21 @@ module.exports = function parseConfig( config, options ) {
 	};
 };
 
+async function parseCoreSource( coreSource, options ) {
+	// An empty source means we should use the latest version of WordPress.
+	if ( ! coreSource ) {
+		const wpVersion = await getLatestWordPressVersion();
+		if ( ! wpVersion ) {
+			throw new ValidationError(
+				'Could not find the latest WordPress version. There may be a network issue.'
+			);
+		}
+
+		coreSource = `WordPress/WordPress#${ wpVersion }`;
+	}
+	return parseSourceString( coreSource, options );
+}
+
 /**
  * Parses a source string into a source object.
  *

packages/env/lib/wordpress.js

@@ -277,13 +277,20 @@ async function readWordPressVersion( coreSource, spinner, debug ) {
  *
  * @return {string} The latest stable version of WordPress, like "6.0.1"
  */
+let CACHED_WP_VERSION;
 async function getLatestWordPressVersion() {
+	// Avoid extra network requests.
+	if ( CACHED_WP_VERSION ) {
+		return CACHED_WP_VERSION;
+	}
+
 	const versions = await got(
 		'https://api.wordpress.org/core/stable-check/1.0/'
 	).json();
 
 	for ( const [ version, status ] of Object.entries( versions ) ) {
 		if ( status === 'latest' ) {
+			CACHED_WP_VERSION = version;
 			return version;
 		}
 	}