Use Vite to load non JS astro configs (#5377)

* Use Vite to load non JS astro configs

* Adding a changeset

* Allow config to not exist

* Use a file url

* Use proload as a fallback

* add missing peerdep

* fix lint mistakes

* Refactor the vite-load

* First check if the file exists

* Pass through fs

* Update packages/astro/src/core/config/vite-load.ts

Co-authored-by: Nate Moore <natemoo-re@users.noreply.github.com>

* Also load astro.config.cjs

* Do search before trying to load

Co-authored-by: Nate Moore <natemoo-re@users.noreply.github.com>

12 files changed, 242 insertions, 66 deletions

diff --git a/.changeset/swift-bees-hope.md b/.changeset/swift-bees-hope.md
new file mode 100644
index 000000000..0bf096e3a
--- /dev/null
+++ b/.changeset/swift-bees-hope.md
@@ -0,0 +1,5 @@
+---
+'astro': patch
+---
+
+Uses vite to load astro.config.ts files
diff --git a/packages/astro/package.json b/packages/astro/package.json
index 279472c6e..13a82395d 100644
--- a/packages/astro/package.json
+++ b/packages/astro/package.json
@@ -111,11 +111,11 @@
     "@babel/plugin-transform-react-jsx": "^7.17.12",
     "@babel/traverse": "^7.18.2",
     "@babel/types": "^7.18.4",
-    "@proload/core": "^0.3.3",
-    "@proload/plugin-tsm": "^0.2.1",
     "@types/babel__core": "^7.1.19",
     "@types/html-escaper": "^3.0.0",
     "@types/yargs-parser": "^21.0.0",
+    "@proload/core": "^0.3.3",
+    "@proload/plugin-tsm": "^0.2.1",
     "boxen": "^6.2.1",
     "ci-info": "^3.3.1",
     "common-ancestor-path": "^1.0.1",
diff --git a/packages/astro/src/cli/index.ts b/packages/astro/src/cli/index.ts
index ddd4acc83..33457a6a1 100644
--- a/packages/astro/src/cli/index.ts
+++ b/packages/astro/src/cli/index.ts
@@ -3,6 +3,7 @@ import * as colors from 'kleur/colors';
 import type { Arguments as Flags } from 'yargs-parser';
 import yargs from 'yargs-parser';
 import { z } from 'zod';
+import fs from 'fs';
 import {
 	createSettings,
 	openConfig,
@@ -88,7 +89,7 @@ async function handleConfigError(
 	e: any,
 	{ cwd, flags, logging }: { cwd?: string; flags?: Flags; logging: LogOptions }
 ) {
-	const path = await resolveConfigPath({ cwd, flags });
+	const path = await resolveConfigPath({ cwd, flags, fs });
 	if (e instanceof Error) {
 		if (path) {
 			error(logging, 'astro', `Unable to load ${colors.bold(path)}\n`);
@@ -173,7 +174,7 @@ async function runCommand(cmd: string, flags: yargs.Arguments) {
 			const { default: devServer } = await import('../core/dev/index.js');
 
 			const configFlag = resolveFlags(flags).config;
-			const configFlagPath = configFlag ? await resolveConfigPath({ cwd: root, flags }) : undefined;
+			const configFlagPath = configFlag ? await resolveConfigPath({ cwd: root, flags, fs }) : undefined;
 
 			await devServer(settings, {
 				configFlag,
diff --git a/packages/astro/src/core/add/index.ts b/packages/astro/src/core/add/index.ts
index 3c2d20a87..536cbe2f9 100644
--- a/packages/astro/src/core/add/index.ts
+++ b/packages/astro/src/core/add/index.ts
@@ -2,7 +2,7 @@ import type { AstroTelemetry } from '@astrojs/telemetry';
 import boxen from 'boxen';
 import { diffWords } from 'diff';
 import { execa } from 'execa';
-import { existsSync, promises as fs } from 'fs';
+import fsMod, { existsSync, promises as fs } from 'fs';
 import { bold, cyan, dim, green, magenta, red, yellow } from 'kleur/colors';
 import ora from 'ora';
 import path from 'path';
@@ -164,7 +164,7 @@ export default async function add(names: string[], { cwd, flags, logging, teleme
 		}
 	}
 
-	const rawConfigPath = await resolveConfigPath({ cwd, flags });
+	const rawConfigPath = await resolveConfigPath({ cwd, flags, fs: fsMod });
 	let configURL = rawConfigPath ? pathToFileURL(rawConfigPath) : undefined;
 
 	if (configURL) {
diff --git a/packages/astro/src/core/config/config.ts b/packages/astro/src/core/config/config.ts
index 13c87fa9a..c17ec6a39 100644
--- a/packages/astro/src/core/config/config.ts
+++ b/packages/astro/src/core/config/config.ts
@@ -1,20 +1,16 @@
 import type { Arguments as Flags } from 'yargs-parser';
 import type { AstroConfig, AstroUserConfig, CLIFlags } from '../../@types/astro';
 
-import load, { ProloadError, resolve } from '@proload/core';
-import loadTypeScript from '@proload/plugin-tsm';
 import fs from 'fs';
 import * as colors from 'kleur/colors';
 import path from 'path';
 import { fileURLToPath, pathToFileURL } from 'url';
-import * as vite from 'vite';
 import { mergeConfig as mergeViteConfig } from 'vite';
 import { AstroError, AstroErrorData } from '../errors/index.js';
 import { LogOptions } from '../logger/core.js';
 import { arraify, isObject, isURL } from '../util.js';
 import { createRelativeSchema } from './schema.js';
-
-load.use([loadTypeScript]);
+import { loadConfigWithVite } from './vite-load.js';
 
 export const LEGACY_ASTRO_CONFIG_KEYS = new Set([
 	'projectRoot',
@@ -151,7 +147,7 @@ interface LoadConfigOptions {
  * instead of the resolved config
  */
 export async function resolveConfigPath(
-	configOptions: Pick<LoadConfigOptions, 'cwd' | 'flags'>
+	configOptions: Pick<LoadConfigOptions, 'cwd' | 'flags'> & { fs: typeof fs }
 ): Promise<string | undefined> {
 	const root = resolveRoot(configOptions.cwd);
 	const flags = resolveFlags(configOptions.flags || {});
@@ -165,14 +161,14 @@ export async function resolveConfigPath(
 	// Resolve config file path using Proload
 	// If `userConfigPath` is `undefined`, Proload will search for `astro.config.[cm]?[jt]s`
 	try {
-		const configPath = await resolve('astro', {
-			mustExist: !!userConfigPath,
-			cwd: root,
-			filePath: userConfigPath,
+		const config = await loadConfigWithVite({
+			configPath: userConfigPath,
+			root,
+			fs: configOptions.fs
 		});
-		return configPath;
+		return config.filePath;
 	} catch (e) {
-		if (e instanceof ProloadError && flags.config) {
+		if (flags.config) {
 			throw new AstroError({
 				...AstroErrorData.ConfigNotFound,
 				message: AstroErrorData.ConfigNotFound.message(flags.config),
@@ -195,7 +191,7 @@ export async function openConfig(configOptions: LoadConfigOptions): Promise<Open
 	const flags = resolveFlags(configOptions.flags || {});
 	let userConfig: AstroUserConfig = {};
 
-	const config = await tryLoadConfig(configOptions, flags, root);
+	const config = await tryLoadConfig(configOptions, root);
 	if (config) {
 		userConfig = config.value;
 	}
@@ -216,7 +212,6 @@ interface TryLoadConfigResult {
 
 async function tryLoadConfig(
 	configOptions: LoadConfigOptions,
-	flags: CLIFlags,
 	root: string
 ): Promise<TryLoadConfigResult | undefined> {
 	const fsMod = configOptions.fsMod ?? fs;
@@ -225,6 +220,7 @@ async function tryLoadConfig(
 		let configPath = await resolveConfigPath({
 			cwd: configOptions.cwd,
 			flags: configOptions.flags,
+			fs: fsMod
 		});
 		if (!configPath) return undefined;
 		if (configOptions.isRestart) {
@@ -246,52 +242,14 @@ async function tryLoadConfig(
 			};
 			configPath = tempConfigPath;
 		}
-
-		const config = await load('astro', {
-			mustExist: !!configPath,
-			cwd: root,
-			filePath: configPath,
+		
+		// Create a vite server to load the config
+		const config = await loadConfigWithVite({
+			configPath,
+			fs: fsMod,
+			root
 		});
-
 		return config as TryLoadConfigResult;
-	} catch (e) {
-		if (e instanceof ProloadError && flags.config) {
-			throw new AstroError({
-				...AstroErrorData.ConfigNotFound,
-				message: AstroErrorData.ConfigNotFound.message(flags.config),
-			});
-		}
-
-		const configPath = await resolveConfigPath(configOptions);
-		if (!configPath) {
-			throw e;
-		}
-
-		// Fallback to use Vite DevServer
-		const viteServer = await vite.createServer({
-			server: { middlewareMode: true, hmr: false },
-			optimizeDeps: { entries: [] },
-			clearScreen: false,
-			appType: 'custom',
-			// NOTE: Vite doesn't externalize linked packages by default. During testing locally,
-			// these dependencies trip up Vite's dev SSR transform. In the future, we should
-			// avoid `vite.createServer` and use `loadConfigFromFile` instead.
-			ssr: {
-				external: ['@astrojs/mdx', '@astrojs/react'],
-			},
-		});
-		try {
-			const mod = await viteServer.ssrLoadModule(configPath);
-
-			if (mod?.default) {
-				return {
-					value: mod.default,
-					filePath: configPath,
-				};
-			}
-		} finally {
-			await viteServer.close();
-		}
 	} finally {
 		await finallyCleanup();
 	}
@@ -306,7 +264,7 @@ export async function loadConfig(configOptions: LoadConfigOptions): Promise<Astr
 	const flags = resolveFlags(configOptions.flags || {});
 	let userConfig: AstroUserConfig = {};
 
-	const config = await tryLoadConfig(configOptions, flags, root);
+	const config = await tryLoadConfig(configOptions, root);
 	if (config) {
 		userConfig = config.value;
 	}
diff --git a/packages/astro/src/core/config/vite-load.ts b/packages/astro/src/core/config/vite-load.ts
new file mode 100644
index 000000000..a701ce7c7
--- /dev/null
+++ b/packages/astro/src/core/config/vite-load.ts
@@ -0,0 +1,138 @@
+import * as vite from 'vite';
+import npath from 'path';
+import { pathToFileURL } from 'url';
+import type fsType from 'fs';
+import { AstroError, AstroErrorData } from '../errors/index.js';
+
+// Fallback for legacy
+import load from '@proload/core';
+import loadTypeScript from '@proload/plugin-tsm';
+
+load.use([loadTypeScript]);
+
+export interface ViteLoader {
+	root: string;
+	viteServer: vite.ViteDevServer;
+}
+
+async function createViteLoader(root: string): Promise<ViteLoader> {
+	const viteServer = await vite.createServer({
+		server: { middlewareMode: true, hmr: false },
+		optimizeDeps: { entries: [] },
+		clearScreen: false,
+		appType: 'custom',
+		ssr: {
+			// NOTE: Vite doesn't externalize linked packages by default. During testing locally,
+			// these dependencies trip up Vite's dev SSR transform. In the future, we should
+			// avoid `vite.createServer` and use `loadConfigFromFile` instead.
+			external: ['@astrojs/tailwind', '@astrojs/mdx', '@astrojs/react']
+		}
+	});
+
+	return {
+		root,
+		viteServer,
+	};
+}
+
+async function stat(fs: typeof fsType, configPath: string, mustExist: boolean): Promise<boolean> {
+	try {
+		await fs.promises.stat(configPath);
+		return true;
+	} catch {
+		if(mustExist) {
+			throw new AstroError({
+				...AstroErrorData.ConfigNotFound,
+				message: AstroErrorData.ConfigNotFound.message(configPath),
+			});
+		}
+		return false;
+	}
+}
+
+async function search(fs: typeof fsType, root: string) {
+	const paths = [
+		'astro.config.mjs',
+		'astro.config.js',
+		'astro.config.ts',
+		'astro.config.mts',
+		'astro.config.cjs',
+		'astro.config.cjs'
+	].map(path => npath.join(root, path));
+
+	for(const file of paths) {
+		// First verify the file event exists
+		const exists = await stat(fs, file, false);
+		if(exists) {
+			return file;
+		}
+	}
+}
+
+interface LoadConfigWithViteOptions {
+	root: string;
+	configPath: string | undefined;
+	fs: typeof fsType;
+}
+
+export async function loadConfigWithVite({ configPath, fs, root }: LoadConfigWithViteOptions): Promise<{
+	value: Record<string, any>;
+	filePath?: string;
+}> {
+	let file: string;
+	if(configPath) {
+		// Go ahead and check if the file exists and throw if not.
+		await stat(fs, configPath, true);
+		file = configPath;
+	} else {
+		const found = await search(fs, root);
+		if(!found) {
+			// No config file found, return an empty config that will be populated with defaults
+			return {
+				value: {},
+				filePath: undefined
+			};
+		} else {
+			file = found;
+		}
+	}
+
+
+	// Try loading with Node import()
+	if(/\.[cm]?js$/.test(file)) {
+		const config = await import(pathToFileURL(file).toString());
+		return {
+			value: config.default ?? {},
+			filePath: file
+		};
+	}
+
+	// Try Loading with Vite
+	let loader: ViteLoader | undefined;
+	try {
+		loader = await createViteLoader(root);
+		const mod = await loader.viteServer.ssrLoadModule(file);
+		return {
+			value: mod.default ?? {},
+			filePath: file
+		}
+	} catch {
+
+		// Try loading with Proload
+		// TODO deprecate - this is only for legacy compatibility
+		const res = await load('astro', {
+			mustExist: true,
+			cwd: root,
+			filePath: file,
+		});
+		return {
+			value: res?.value ?? {},
+			filePath: file
+		};
+
+	} finally {
+		if(loader) {
+			await loader.viteServer.close();
+		}
+	}
+}
diff --git a/packages/astro/test/fixtures/tailwindcss-ts/astro.config.ts b/packages/astro/test/fixtures/tailwindcss-ts/astro.config.ts
new file mode 100644
index 000000000..0a5f36a87
--- /dev/null
+++ b/packages/astro/test/fixtures/tailwindcss-ts/astro.config.ts
@@ -0,0 +1,7 @@
+import { defineConfig } from 'astro/config';
+import tailwind from "@astrojs/tailwind";
+
+// https://astro.build/config
+export default defineConfig({
+  integrations: [tailwind()]
+});
\ No newline at end of file
diff --git a/packages/astro/test/fixtures/tailwindcss-ts/package.json b/packages/astro/test/fixtures/tailwindcss-ts/package.json
new file mode 100644
index 000000000..78ead447f
--- /dev/null
+++ b/packages/astro/test/fixtures/tailwindcss-ts/package.json
@@ -0,0 +1,11 @@
+{
+  "name": "@test/tailwindcss-ts",
+  "version": "0.0.0",
+  "private": true,
+  "dependencies": {
+    "@astrojs/tailwind": "workspace:*",
+    "astro": "workspace:*",
+    "tailwindcss": "^3.2.4",
+    "postcss": ">=8.3.3 <9.0.0"
+  }
+}
diff --git a/packages/astro/test/fixtures/tailwindcss-ts/tailwind.config.cjs b/packages/astro/test/fixtures/tailwindcss-ts/tailwind.config.cjs
new file mode 100644
index 000000000..f4033a222
--- /dev/null
+++ b/packages/astro/test/fixtures/tailwindcss-ts/tailwind.config.cjs
@@ -0,0 +1,4 @@
+/** @type {import('tailwindcss').Config} */
+module.exports = {
+	content: ['src/**/*.{astro,tsx}']
+};
\ No newline at end of file
diff --git a/packages/astro/test/units/dev/restart.test.js b/packages/astro/test/units/dev/restart.test.js
index 2e78f789d..96c60c608 100644
--- a/packages/astro/test/units/dev/restart.test.js
+++ b/packages/astro/test/units/dev/restart.test.js
@@ -7,6 +7,8 @@ import {
 	startContainer,
 } from '../../../dist/core/dev/index.js';
 import { createFs, createRequestAndResponse, triggerFSEvent } from '../test-utils.js';
+import { createSettings, openConfig } from '../../../dist/core/config/index.js';
+import { defaultLogging } from '../../test-utils.js';
 
 const root = new URL('../../fixtures/alias/', import.meta.url);
 
@@ -109,4 +111,40 @@ describe('dev container restarts', () => {
 			await restart.container.close();
 		}
 	});
+
+	it('Is able to restart project using Tailwind + astro.config.ts', async () => {
+		const troot = new URL('../../fixtures/tailwindcss-ts/', import.meta.url);
+		const fs = createFs(
+			{
+				'/src/pages/index.astro': ``,
+				'/astro.config.ts': ``,
+			},
+			troot
+		);
+
+		const { astroConfig } = await openConfig({
+			cwd: troot,
+			flags: {},
+			cmd: 'dev',
+			logging: defaultLogging,
+		});
+		const settings = createSettings(astroConfig);
+
+		let restart = await createContainerWithAutomaticRestart({
+			params: { fs, root, settings },
+		});
+		await startContainer(restart.container);
+		expect(isStarted(restart.container)).to.equal(true);
+
+		try {
+			// Trigger a change
+			let restartComplete = restart.restarted();
+			triggerFSEvent(restart.container, fs, '/astro.config.ts', 'change');
+			await restartComplete;
+
+			expect(isStarted(restart.container)).to.equal(true);
+		} finally {
+			await restart.container.close();
+		}
+	});
 });
diff --git a/packages/integrations/image/src/index.ts b/packages/integrations/image/src/index.ts
index ebb91e17b..43f64935b 100644
--- a/packages/integrations/image/src/index.ts
+++ b/packages/integrations/image/src/index.ts
@@ -82,7 +82,9 @@ export default function integration(options: IntegrationOptions = {}): AstroInte
 			'astro:config:setup': async ({ command, config, updateConfig, injectRoute }) => {
 				needsBuildConfig = !config.build?.server;
 				_config = config;
-				updateConfig({ vite: getViteConfiguration(command === 'dev') });
+				updateConfig({
+					vite: getViteConfiguration(command === 'dev'),
+				});
 
 				if (command === 'dev' || config.output === 'server') {
 					injectRoute({
diff --git a/pnpm-lock.yaml b/pnpm-lock.yaml
index b4f3a0ac2..c6797e1e8 100644
--- a/pnpm-lock.yaml
+++ b/pnpm-lock.yaml
@@ -2390,6 +2390,18 @@ importers:
       postcss: 8.4.19
       tailwindcss: 3.2.4_postcss@8.4.19
 
+  packages/astro/test/fixtures/tailwindcss-ts:
+    specifiers:
+      '@astrojs/tailwind': workspace:*
+      astro: workspace:*
+      postcss: '>=8.3.3 <9.0.0'
+      tailwindcss: ^3.2.4
+    dependencies:
+      '@astrojs/tailwind': link:../../../../integrations/tailwind
+      astro: link:../../..
+      postcss: 8.4.19
+      tailwindcss: 3.2.4_postcss@8.4.19
+
   packages/astro/test/fixtures/third-party-astro:
     specifiers:
       astro: workspace:*