Prevent externalized adapters from breaking build

.changeset/new-boats-flash.md

@@ -0,0 +1,5 @@
+---
+'astro': patch
+---
+
+Fix adapter causing Netlify to break

packages/astro/src/core/build/plugins/plugin-ssr.ts

@@ -19,6 +19,26 @@ import { getComponentFromVirtualModulePageName, getVirtualModulePageName } from
 export const SSR_VIRTUAL_MODULE_ID = '@astrojs-ssr-virtual-entry';
 export const RESOLVED_SSR_VIRTUAL_MODULE_ID = '\0' + SSR_VIRTUAL_MODULE_ID;
 
+const ADAPTER_VIRTUAL_MODULE_ID = '@astrojs-ssr-adapter';
+const RESOLVED_ADAPTER_VIRTUAL_MODULE_ID = '\0' + ADAPTER_VIRTUAL_MODULE_ID;
+
+function vitePluginAdapter(adapter: AstroAdapter): VitePlugin {
+	return {
+		name: '@astrojs/vite-plugin-astro-adapter',
+		enforce: 'post',
+		resolveId(id) {
+			if (id === ADAPTER_VIRTUAL_MODULE_ID) {
+				return RESOLVED_ADAPTER_VIRTUAL_MODULE_ID;
+			}
+		},
+		async load(id) {
+			if(id === RESOLVED_ADAPTER_VIRTUAL_MODULE_ID) {
+				return `export * from '${adapter.serverEntrypoint}';`;
+			}
+		},
+	};
+}
+
 function vitePluginSSR(
 	internals: BuildInternals,
 	adapter: AstroAdapter,
@@ -39,7 +59,7 @@ function vitePluginSSR(
 
 			const adapterServerEntrypoint = options.settings.adapter?.serverEntrypoint;
 			if (adapterServerEntrypoint) {
-				inputs.add(adapterServerEntrypoint);
+				inputs.add(ADAPTER_VIRTUAL_MODULE_ID);
 			}
 
 			inputs.add(SSR_VIRTUAL_MODULE_ID);
@@ -119,14 +139,19 @@ export function pluginSSR(
 		targets: ['server'],
 		hooks: {
 			'build:before': () => {
-				let vitePlugin =
+				const adapter = options.settings.adapter!;
+				let ssrPlugin =
 					ssr && functionPerRouteEnabled === false
-						? vitePluginSSR(internals, options.settings.adapter!, options)
+						? vitePluginSSR(internals, adapter, options)
 						: undefined;
+				const vitePlugin = [vitePluginAdapter(adapter)];
+				if(ssrPlugin) {
+					vitePlugin.unshift(ssrPlugin);
+				}
 
 				return {
 					enforce: 'after-user-plugins',
-					vitePlugin,
+					vitePlugin: vitePlugin,
 				};
 			},
 			'build:post': async () => {
@@ -231,10 +256,15 @@ export function pluginSSRSplit(
 		targets: ['server'],
 		hooks: {
 			'build:before': () => {
-				let vitePlugin =
+				const adapter = options.settings.adapter!;
+				let ssrPlugin =
 					ssr && functionPerRouteEnabled
-						? vitePluginSSRSplit(internals, options.settings.adapter!, options)
+						? vitePluginSSRSplit(internals, adapter, options)
 						: undefined;
+				const vitePlugin = [vitePluginAdapter(adapter)];
+				if(ssrPlugin) {
+					vitePlugin.unshift(ssrPlugin);
+				}
 
 				return {
 					enforce: 'after-user-plugins',
@@ -251,7 +281,7 @@ function generateSSRCode(settings: AstroSettings, adapter: AstroAdapter, middlew
 
 	const imports = [
 		`import { renderers } from '${RENDERERS_MODULE_ID}';`,
-		`import * as serverEntrypointModule from '${adapter.serverEntrypoint}';`,
+		`import * as serverEntrypointModule from '${ADAPTER_VIRTUAL_MODULE_ID}';`,
 		`import { manifest as defaultManifest } from '${SSR_MANIFEST_VIRTUAL_MODULE_ID}';`,
 		edgeMiddleware ? `` : `import { onRequest as middleware } from '${middlewareId}';`,
 		settings.config.experimental.serverIslands

packages/astro/test/ssr-split-manifest.test.js

@@ -1,6 +1,5 @@
 import assert from 'node:assert/strict';
 import { existsSync, readFileSync } from 'node:fs';
-import { resolve } from 'node:path';
 import { before, describe, it } from 'node:test';
 import { fileURLToPath } from 'node:url';
 import * as cheerio from 'cheerio';
@@ -62,12 +61,10 @@ describe('astro:ssr-manifest, split', () => {
 	});
 
 	it('should correctly emit the the pre render page', async () => {
-		const text = readFileSync(
-			resolve('./test/fixtures/ssr-split-manifest/dist/client/prerender/index.html'),
-			{
-				encoding: 'utf8',
-			},
-		);
+		const indexUrl = new URL('./fixtures/ssr-split-manifest/dist/client/prerender/index.html', import.meta.url);
+		const text = readFileSync(indexUrl, {
+			encoding: 'utf8',
+		});
 		assert.equal(text.includes('<title>Pre render me</title>'), true);
 	});