fix(remix-dev/vite): attach CSS from shared chunks to routes

.changeset/itchy-rabbits-fly.md

@@ -0,0 +1,5 @@
+---
+"@remix-run/dev": patch
+---
+
+Attach CSS from shared chunks to routes in Vite build

integration/vite-build-test.ts

@@ -107,7 +107,7 @@ test.describe("Vite build", () => {
           import { useEffect, useState } from "react";
           import { json } from "@remix-run/node";
           import { useLoaderData } from "@remix-run/react";
-          
+
           import { serverOnly1, serverOnly2 } from "../utils.server";
 
           export const loader = () => {
@@ -138,6 +138,32 @@ test.describe("Vite build", () => {
 
           <MdxComponent />
         `,
+        "app/routes/code-split1.tsx": js`
+          import { CodeSplitComponent } from "../code-split-component";
+
+          export default function CodeSplit1Route() {
+            return <div id="code-split1"><CodeSplitComponent /></div>;
+          }
+        `,
+        "app/routes/code-split2.tsx": js`
+          import { CodeSplitComponent } from "../code-split-component";
+
+          export default function CodeSplit2Route() {
+            return <div id="code-split2"><CodeSplitComponent /></div>;
+          }
+        `,
+        "app/code-split-component.tsx": js`
+          import classes from "./code-split.module.css";
+
+          export function CodeSplitComponent() {
+            return <span className={classes.test}>ok</span>
+          }
+        `,
+        "app/code-split.module.css": js`
+          .test {
+            background-color: rgb(255, 170, 0);
+          }
+        `,
       },
     });
 
@@ -206,4 +232,26 @@ test.describe("Vite build", () => {
 
     expect(pageErrors).toEqual([]);
   });
+
+  test("supports code-split css", async ({ page }) => {
+    let pageErrors: unknown[] = [];
+    page.on("pageerror", (error) => pageErrors.push(error));
+
+    let app = new PlaywrightFixture(appFixture, page);
+    await app.goto("/code-split1");
+    expect(
+      await page
+        .locator("#code-split1 span")
+        .evaluate((e) => window.getComputedStyle(e).backgroundColor)
+    ).toBe("rgb(255, 170, 0)");
+
+    await app.goto("/code-split2");
+    expect(
+      await page
+        .locator("#code-split2 span")
+        .evaluate((e) => window.getComputedStyle(e).backgroundColor)
+    ).toBe("rgb(255, 170, 0)");
+
+    expect(pageErrors).toEqual([]);
+  });
 });

packages/remix-dev/vite/plugin.ts

@@ -7,6 +7,7 @@ import {
   type Connect,
   type Plugin as VitePlugin,
   type Manifest as ViteManifest,
+  type ManifestChunk,
   type ResolvedConfig as ResolvedViteConfig,
   type ViteDevServer,
   type UserConfig as ViteUserConfig,
@@ -120,38 +121,69 @@ const getHash = (source: BinaryLike, maxLength?: number): string => {
 
 const resolveBuildAssetPaths = (
   pluginConfig: ResolvedRemixVitePluginConfig,
-  manifest: ViteManifest,
+  viteManifest: ViteManifest,
   absoluteFilePath: string
 ): Manifest["entry"] & { css: string[] } => {
   let rootRelativeFilePath = path.relative(
     pluginConfig.rootDirectory,
     absoluteFilePath
   );
   let manifestKey = normalizePath(rootRelativeFilePath);
-  let manifestEntry = manifest[manifestKey];
+  let entryChunk = viteManifest[manifestKey];
 
-  if (!manifestEntry) {
-    let knownManifestKeys = Object.keys(manifest)
+  if (!entryChunk) {
+    let knownManifestKeys = Object.keys(viteManifest)
       .map((key) => '"' + key + '"')
       .join(", ");
     throw new Error(
       `No manifest entry found for "${manifestKey}". Known manifest keys: ${knownManifestKeys}`
     );
   }
 
+  let chunks = resolveDependantChunks(viteManifest, entryChunk);
+
   return {
-    module: `${pluginConfig.publicPath}${manifestEntry.file}`,
+    module: `${pluginConfig.publicPath}${entryChunk.file}`,
     imports:
-      manifestEntry.imports?.map((imported) => {
-        return `${pluginConfig.publicPath}${manifest[imported].file}`;
+      dedupe(chunks.flatMap((e) => e.imports ?? [])).map((imported) => {
+        return `${pluginConfig.publicPath}${viteManifest[imported].file}`;
       }) ?? [],
     css:
-      manifestEntry.css?.map((href) => {
+      dedupe(chunks.flatMap((e) => e.css ?? [])).map((href) => {
         return `${pluginConfig.publicPath}${href}`;
       }) ?? [],
   };
 };
 
+function resolveDependantChunks(
+  viteManifest: ViteManifest,
+  entryChunk: ManifestChunk
+): ManifestChunk[] {
+  let chunks = new Set<ManifestChunk>();
+
+  function walk(chunk: ManifestChunk) {
+    if (chunks.has(chunk)) {
+      return;
+    }
+
+    if (chunk.imports) {
+      for (let importKey of chunk.imports) {
+        walk(viteManifest[importKey]);
+      }
+    }
+
+    chunks.add(chunk);
+  }
+
+  walk(entryChunk);
+
+  return Array.from(chunks);
+}
+
+function dedupe<T>(array: T[]): T[] {
+  return [...new Set(array)];
+}
+
 const writeFileSafe = async (file: string, contents: string): Promise<void> => {
   await fs.mkdir(path.dirname(file), { recursive: true });
   await fs.writeFile(file, contents);