5 files changed, 17 insertions, 7 deletions
diff --git a/packages/astro/src/build.ts b/packages/astro/src/build.ts
index 6f60c862a..28c9c90b7 100644
--- a/packages/astro/src/build.ts
+++ b/packages/astro/src/build.ts
@@ -149,7 +149,7 @@ ${stack}
             astroRuntime.load(url).then((result) => {
               if (result.statusCode !== 200) {
                 if (result.statusCode === 404) {
-                  throw new Error(`${buildState[id].srcPath.href}: could not find "${path.basename(url)}"`);
+                  throw new Error(`${buildState[id].srcPath.href}: could not find "${url}"`);
                 }
                 // there shouldn’t be a build error here
                 throw (result as any).error || new Error(`unexpected status ${result.statusCode} when loading ${url}`);
diff --git a/packages/astro/src/build/bundle/css.ts b/packages/astro/src/build/bundle/css.ts
index 2cd59f24d..6da84da02 100644
--- a/packages/astro/src/build/bundle/css.ts
+++ b/packages/astro/src/build/bundle/css.ts
@@ -5,7 +5,7 @@ import { performance } from 'perf_hooks';
 import shorthash from 'shorthash';
 import cheerio from 'cheerio';
 import esbuild from 'esbuild';
-import { getDistPath, getSrcPath, stopTimer } from '../util.js';
+import { getDistPath, getSrcPath, IS_ASTRO_FILE_URL, stopTimer } from '../util.js';
 import { debug } from '../../logger.js';
 
 // config
@@ -46,7 +46,9 @@ export async function bundleCSS({
   for (const pageUrl of sortedPages) {
     const { css } = depTree[pageUrl];
     for (const cssUrl of css.keys()) {
-      if (cssMap.has(cssUrl)) {
+      if (!IS_ASTRO_FILE_URL.test(cssUrl)) {
+        // do not add to cssMap, leave as-is.
+      } else if (cssMap.has(cssUrl)) {
         // scenario 1: if multiple URLs require this CSS, upgrade to common chunk
         cssMap.set(cssUrl, COMMON_URL);
       } else {
@@ -83,7 +85,7 @@ export async function bundleCSS({
   await Promise.all(
     Object.keys(buildState).map(async (id) => {
       if (buildState[id].contentType !== 'text/css') return;
-      const { code } = await esbuild.transform(buildState[id].contents as string, {
+      const { code } = await esbuild.transform(buildState[id].contents.toString(), {
         loader: 'css',
         minify: true,
       });
diff --git a/packages/astro/src/build/bundle/js.ts b/packages/astro/src/build/bundle/js.ts
index 7340d396b..4deecb30a 100644
--- a/packages/astro/src/build/bundle/js.ts
+++ b/packages/astro/src/build/bundle/js.ts
@@ -6,6 +6,7 @@ import { fileURLToPath } from 'url';
 import { rollup } from 'rollup';
 import { terser } from 'rollup-plugin-terser';
 import { createBundleStats, addBundleStats, BundleStatsMap } from '../stats.js';
+import { IS_ASTRO_FILE_URL } from '../util.js';
 
 interface BundleOptions {
   dist: URL;
@@ -24,12 +25,13 @@ export function collectJSImports(buildState: BuildOutput): Set<string> {
 /** Bundle JS action */
 export async function bundleJS(imports: Set<string>, { astroRuntime, dist }: BundleOptions): Promise<BundleStatsMap> {
   const ROOT = 'astro:root';
+  const validImports = [...imports].filter((url) => IS_ASTRO_FILE_URL.test(url));
   const root = `
-  ${[...imports].map((url) => `import '${url}';`).join('\n')}
+  ${validImports.map((url) => `import '${url}';`).join('\n')}
 `;
 
   const inputOptions: InputOptions = {
-    input: [...imports],
+    input: validImports,
     plugins: [
       {
         name: 'astro:build',
diff --git a/packages/astro/src/build/util.ts b/packages/astro/src/build/util.ts
index 3c74086e2..e3f2aaa17 100644
--- a/packages/astro/src/build/util.ts
+++ b/packages/astro/src/build/util.ts
@@ -5,6 +5,12 @@ import fs from 'fs';
 import path from 'path';
 import { URL } from 'url';
 
+/**
+ * Only Astro-handled imports need bundling. Any other imports are considered
+ * a part of `public/`, and should not be touched.
+ */
+export const IS_ASTRO_FILE_URL = /^\/(_astro|_astro_frontend|_snowpack)\//;
+
 /** Normalize URL to its canonical form */
 export function canonicalURL(url: string, base?: string): URL {
   let pathname = url.replace(/\/index.html$/, ''); // index.html is not canonical
diff --git a/packages/astro/src/runtime.ts b/packages/astro/src/runtime.ts
index 165df0a02..4145753ed 100644
--- a/packages/astro/src/runtime.ts
+++ b/packages/astro/src/runtime.ts
@@ -283,7 +283,7 @@ async function createSnowpack(astroConfig: AstroConfig, options: CreateSnowpackO
   };
 
   const mountOptions = {
-    ...(existsSync(astroConfig.public) ? { [fileURLToPath(astroConfig.public)]: '/' } : {}),
+    ...(existsSync(astroConfig.public) ? { [fileURLToPath(astroConfig.public)]: { url: '/', static: true, resolve: false } } : {}),
     [fileURLToPath(frontendPath)]: '/_astro_frontend',
     [fileURLToPath(src)]: '/_astro/src', // must be last (greediest)
   };