Fix use of frameworks in the static build (#2367)

* Fix use of frameworks in the static build

* Adding a changeset

* fix typescript

* Empty out the directory before running the builds

* Use a util to empty the directory

* Only empty the outdir if needed

* Move prepareOutDir to its own module

* Prepare outDir is actually sync

8 files changed, 136 insertions, 7 deletions

diff --git a/.changeset/long-eagles-care.md b/.changeset/long-eagles-care.md
new file mode 100644
index 000000000..716b9b3ab
--- /dev/null
+++ b/.changeset/long-eagles-care.md
@@ -0,0 +1,5 @@
+---
+'astro': patch
+---
+
+Fixes use of framework renderers in the static build
diff --git a/packages/astro/src/@types/astro.ts b/packages/astro/src/@types/astro.ts
index 2e60da3b7..3c1548698 100644
--- a/packages/astro/src/@types/astro.ts
+++ b/packages/astro/src/@types/astro.ts
@@ -279,6 +279,8 @@ export interface Renderer {
 	name: string;
 	/** Import statement for renderer */
 	source?: string;
+	/** Import statement for the server renderer */
+	serverEntry: string;
 	/** Scripts to be injected before component */
 	polyfills?: string[];
 	/** Polyfills that need to run before hydration ever occurs */
diff --git a/packages/astro/src/core/build/fs.ts b/packages/astro/src/core/build/fs.ts
new file mode 100644
index 000000000..f557b3cbf
--- /dev/null
+++ b/packages/astro/src/core/build/fs.ts
@@ -0,0 +1,28 @@
+import type { AstroConfig } from '../../@types/astro';
+
+import fs from 'fs';
+import npath from 'path';
+import { fileURLToPath } from 'url';
+
+export function emptyDir(dir: string, skip?: Set<string>): void {
+  for (const file of fs.readdirSync(dir)) {
+    if (skip?.has(file)) {
+      continue
+    }
+    const abs = npath.resolve(dir, file)
+    // baseline is Node 12 so can't use rmSync :(
+    if (fs.lstatSync(abs).isDirectory()) {
+      emptyDir(abs)
+      fs.rmdirSync(abs)
+    } else {
+      fs.unlinkSync(abs)
+    }
+  }
+}
+
+export function prepareOutDir(astroConfig: AstroConfig) {
+	const outDir = fileURLToPath(astroConfig.dist);
+	if (fs.existsSync(outDir)) {
+		return emptyDir(outDir, new Set(['.git']));
+	}
+}
diff --git a/packages/astro/src/core/build/static-build.ts b/packages/astro/src/core/build/static-build.ts
index 40afe728e..b21c81b00 100644
--- a/packages/astro/src/core/build/static-build.ts
+++ b/packages/astro/src/core/build/static-build.ts
@@ -1,6 +1,6 @@
 import type { OutputChunk, OutputAsset, PreRenderedChunk, RollupOutput } from 'rollup';
 import type { Plugin as VitePlugin, UserConfig } from '../vite';
-import type { AstroConfig, RouteCache, SSRElement } from '../../@types/astro';
+import type { AstroConfig, Renderer, RouteCache, SSRElement } from '../../@types/astro';
 import type { AllPagesData } from './types';
 import type { LogOptions } from '../logger';
 import type { ViteConfigWithSSR } from '../create-vite';
@@ -19,6 +19,7 @@ import { rollupPluginAstroBuildCSS } from '../../vite-plugin-build-css/index.js'
 import { getParamsAndProps } from '../ssr/index.js';
 import { createResult } from '../ssr/result.js';
 import { renderPage } from '../../runtime/server/index.js';
+import { prepareOutDir } from './fs.js';
 
 export interface StaticBuildOptions {
 	allPages: AllPagesData;
@@ -35,6 +36,8 @@ function addPageName(pathname: string, opts: StaticBuildOptions): void {
 	opts.pageNames.push(pathname.replace(/\/?$/, pathrepl).replace(/^\//, ''));
 }
 
+
+
 // Determines of a Rollup chunk is an entrypoint page.
 function chunkIsPage(output: OutputAsset | OutputChunk, internals: BuildInternals) {
 	if (output.type !== 'chunk') {
@@ -82,6 +85,11 @@ export async function staticBuild(opts: StaticBuildOptions) {
 	// Build internals needed by the CSS plugin
 	const internals = createBuildInternals();
 
+	// Empty out the dist folder, if needed. Vite has a config for doing this
+	// but because we are running 2 vite builds in parallel, that would cause a race
+	// condition, so we are doing it ourselves
+	prepareOutDir(astroConfig);
+
 	// Run the SSR build and client build in parallel
 	const [ssrResult] = (await Promise.all([ssrBuild(opts, internals, pageInput), clientBuild(opts, internals, jsInput)])) as RollupOutput[];
 
@@ -97,7 +105,7 @@ async function ssrBuild(opts: StaticBuildOptions, internals: BuildInternals, inp
 		logLevel: 'error',
 		mode: 'production',
 		build: {
-			emptyOutDir: true,
+			emptyOutDir: false,
 			minify: false,
 			outDir: fileURLToPath(astroConfig.dist),
 			ssr: true,
@@ -163,18 +171,41 @@ async function clientBuild(opts: StaticBuildOptions, internals: BuildInternals,
 	});
 }
 
+async function collectRenderers(opts: StaticBuildOptions): Promise<Renderer[]> {
+	// All of the PageDatas have the same renderers, so just grab one.
+	const pageData = Object.values(opts.allPages)[0];
+	// These renderers have been loaded through Vite. To generate pages
+	// we need the ESM loaded version. This creates that.
+	const viteLoadedRenderers = pageData.preload[0];
+
+	const renderers = await Promise.all(viteLoadedRenderers.map(async r => {
+		const mod = await import(r.serverEntry);
+		return Object.create(r, {
+			ssr: {
+				value: mod.default
+			}
+		}) as Renderer;
+	}));
+
+	return renderers;
+}
+
 async function generatePages(result: RollupOutput, opts: StaticBuildOptions, internals: BuildInternals, facadeIdToPageDataMap: Map<string, PageBuildData>) {
 	debug(opts.logging, 'generate', 'End build step, now generating');
+
+	// Get renderers to be shared for each page generation.
+	const renderers = await collectRenderers(opts);
+
 	const generationPromises = [];
 	for (let output of result.output) {
 		if (chunkIsPage(output, internals)) {
-			generationPromises.push(generatePage(output as OutputChunk, opts, internals, facadeIdToPageDataMap));
+			generationPromises.push(generatePage(output as OutputChunk, opts, internals, facadeIdToPageDataMap, renderers));
 		}
 	}
 	await Promise.all(generationPromises);
 }
 
-async function generatePage(output: OutputChunk, opts: StaticBuildOptions, internals: BuildInternals, facadeIdToPageDataMap: Map<string, PageBuildData>) {
+async function generatePage(output: OutputChunk, opts: StaticBuildOptions, internals: BuildInternals, facadeIdToPageDataMap: Map<string, PageBuildData>, renderers: Renderer[]) {
 	const { astroConfig } = opts;
 
 	let url = new URL('./' + output.fileName, astroConfig.dist);
@@ -198,6 +229,7 @@ async function generatePage(output: OutputChunk, opts: StaticBuildOptions, inter
 		internals,
 		linkIds,
 		Component,
+		renderers,
 	};
 
 	const renderPromises = pageData.paths.map((path) => {
@@ -211,16 +243,17 @@ interface GeneratePathOptions {
 	internals: BuildInternals;
 	linkIds: string[];
 	Component: AstroComponentFactory;
+	renderers: Renderer[];
 }
 
 async function generatePath(pathname: string, opts: StaticBuildOptions, gopts: GeneratePathOptions) {
 	const { astroConfig, logging, origin, pageNames, routeCache } = opts;
-	const { Component, internals, linkIds, pageData } = gopts;
+	const { Component, internals, linkIds, pageData, renderers } = gopts;
 
 	// This adds the page name to the array so it can be shown as part of stats.
 	addPageName(pathname, opts);
 
-	const [renderers, mod] = pageData.preload;
+	const [,mod] = pageData.preload;
 
 	try {
 		const [params, pageProps] = await getParamsAndProps({
diff --git a/packages/astro/src/core/ssr/index.ts b/packages/astro/src/core/ssr/index.ts
index eb6e3c4e8..fd1b1694c 100644
--- a/packages/astro/src/core/ssr/index.ts
+++ b/packages/astro/src/core/ssr/index.ts
@@ -52,9 +52,10 @@ async function resolveRenderer(viteServer: vite.ViteDevServer, renderer: string,
 
 	resolvedRenderer.name = name;
 	if (client) resolvedRenderer.source = path.posix.join(renderer, client);
+	resolvedRenderer.serverEntry = path.posix.join(renderer, server);
 	if (Array.isArray(hydrationPolyfills)) resolvedRenderer.hydrationPolyfills = hydrationPolyfills.map((src: string) => path.posix.join(renderer, src));
 	if (Array.isArray(polyfills)) resolvedRenderer.polyfills = polyfills.map((src: string) => path.posix.join(renderer, src));
-	const { url } = await viteServer.moduleGraph.ensureEntryFromUrl(path.posix.join(renderer, server));
+	const { url } = await viteServer.moduleGraph.ensureEntryFromUrl(resolvedRenderer.serverEntry);
 	const { default: rendererSSR } = await viteServer.ssrLoadModule(url);
 	resolvedRenderer.ssr = rendererSSR;
 
diff --git a/packages/astro/test/fixtures/static-build-frameworks/src/components/PCounter.jsx b/packages/astro/test/fixtures/static-build-frameworks/src/components/PCounter.jsx
new file mode 100644
index 000000000..6a67d6203
--- /dev/null
+++ b/packages/astro/test/fixtures/static-build-frameworks/src/components/PCounter.jsx
@@ -0,0 +1,19 @@
+import { h } from 'preact';
+import { useState } from 'preact/hooks';
+
+export default function Counter({ children }) {
+	const [count, setCount] = useState(0);
+	const add = () => setCount((i) => i + 1);
+	const subtract = () => setCount((i) => i - 1);
+
+	return (
+		<>
+			<div class="counter">
+				<button onClick={subtract}>-</button>
+				<pre>{count}</pre>
+				<button onClick={add}>+</button>
+			</div>
+			<div class="counter-message">{children}</div>
+		</>
+	);
+}
diff --git a/packages/astro/test/fixtures/static-build-frameworks/src/pages/index.astro b/packages/astro/test/fixtures/static-build-frameworks/src/pages/index.astro
new file mode 100644
index 000000000..53e5ce551
--- /dev/null
+++ b/packages/astro/test/fixtures/static-build-frameworks/src/pages/index.astro
@@ -0,0 +1,12 @@
+---
+import PCounter from '../components/PCounter.jsx';
+---
+<html>
+<head>
+<title>Testing</title>
+</head>
+<body>
+<h1>Testing</h1>
+<PCounter client:load />
+</body>
+</html>
diff --git a/packages/astro/test/static-build-frameworks.test.js b/packages/astro/test/static-build-frameworks.test.js
new file mode 100644
index 000000000..22ba13b3c
--- /dev/null
+++ b/packages/astro/test/static-build-frameworks.test.js
@@ -0,0 +1,29 @@
+import { expect } from 'chai';
+import cheerio from 'cheerio';
+import { loadFixture } from './test-utils.js';
+
+function addLeadingSlash(path) {
+	return path.startsWith('/') ? path : '/' + path;
+}
+
+describe('Static build - frameworks', () => {
+	let fixture;
+
+	before(async () => {
+		fixture = await loadFixture({
+			projectRoot: './fixtures/static-build-frameworks/',
+			renderers: [
+				'@astrojs/renderer-preact'
+			],
+			buildOptions: {
+				experimentalStaticBuild: true,
+			},
+		});
+		await fixture.build();
+	});
+
+	it('can build preact', async () => {
+		const html = await fixture.readFile('/index.html');
+		expect(html).to.be.a('string');
+	});
+});