test: skip CSS Modules migration in deploy harness (#3519)

* fix(init): skip CSS Modules migration in deploy harness

* test(init): update deploy harness command assertions

Author: james-elicx

packages/vinext/src/cli.ts

@@ -304,6 +304,7 @@ async function initCommand() {
     root: process.cwd(),
     port: parsed.port,
     skipCheck,
+    skipCssModules: rawArgs.includes("--skip-css-modules"),
     force,
     install,
     ...initOptions,

packages/vinext/src/init.ts

@@ -96,6 +96,8 @@ export type InitOptions = {
   port?: number | false;
   /** Skip the compatibility check step */
   skipCheck?: boolean;
+  /** @internal — skip CSS Modules migration in the Next.js deploy harness. */
+  skipCssModules?: boolean;
   /** Force overwrite even if vite.config.ts exists */
   force?: boolean;
   /** Deployment target selected by the user */
@@ -651,7 +653,7 @@ export async function init(options: InitOptions): Promise<InitResult> {
   const viteConfigExists = hasViteConfig(root);
 
   const isApp = detectProject(root).isAppRouter;
-  const hasCssModules = scanCssModuleFiles(root);
+  const hasCssModules = !options.skipCssModules && scanCssModuleFiles(root);
   const pmName = detectPackageManagerName(root);
   const shouldInstall = options.install ?? true;
 

scripts/e2e-deploy.sh

@@ -741,20 +741,22 @@ fi
 # --skip-check avoids the interactive compat report, --force overwrites any
 # existing vite.config.ts. Dep installation is a no-op since we already injected
 # them above.
+# --skip-css-modules keeps native CSS Module exports for Next.js fixtures
+# that import named classes instead of the default-only migration shim.
 #
 # vinext loads CJS next.config.js in `"type": "module"` packages via a temp
 # .cjs sibling (see config/next-config.ts), so we don't rewrite the user's
 # config file here.
 if [ "${VINEXT_HARNESS_DIR}" != "${VINEXT_DIR}" ]; then
-  "${VINEXT_BIN}" init --platform=node --skip-check --force >> "${BUILD_LOG}" 2>&1
+  "${VINEXT_BIN}" init --platform=node --skip-check --skip-css-modules --force >> "${BUILD_LOG}" 2>&1
   "${VINEXT_BIN}" build --prerender-all >> "${BUILD_LOG}" 2>&1
 else
   VITE_BIN="./node_modules/.bin/vite"
   if [ ! -x "${VITE_BIN}" ]; then
     echo "pnpm install failed: ${VITE_BIN} not found or not executable" >&2
     exit 1
   fi
-  "${VINEXT_BIN}" init --platform=node --skip-check --force --prerender >> "${BUILD_LOG}" 2>&1
+  "${VINEXT_BIN}" init --platform=node --skip-check --skip-css-modules --force --prerender >> "${BUILD_LOG}" 2>&1
   "${VITE_BIN}" build >> "${BUILD_LOG}" 2>&1
 fi
 

tests/e2e-deploy-script.test.ts

@@ -267,11 +267,11 @@ describe("Next.js deploy harness", () => {
 
     expect(script).toContain('if [ "${VINEXT_HARNESS_DIR}" != "${VINEXT_DIR}" ]; then');
     expect(script).toContain(
-      '"${VINEXT_BIN}" init --platform=node --skip-check --force >> "${BUILD_LOG}" 2>&1',
+      '"${VINEXT_BIN}" init --platform=node --skip-check --skip-css-modules --force >> "${BUILD_LOG}" 2>&1',
     );
     expect(script).toContain('"${VINEXT_BIN}" build --prerender-all >> "${BUILD_LOG}" 2>&1');
     expect(script).toContain(
-      '"${VINEXT_BIN}" init --platform=node --skip-check --force --prerender',
+      '"${VINEXT_BIN}" init --platform=node --skip-check --skip-css-modules --force --prerender',
     );
   });
 

tests/init.test.ts

@@ -43,6 +43,26 @@ function readFile(dir: string, relativePath: string): string {
 }
 
 describe("CSS Modules discovery", () => {
+  // Next.js deploy fixtures rely on named CSS Module exports:
+  // https://github.com/vercel/next.js/blob/v16.2.6/test/e2e/app-dir/scss/basic-module/pages/index.js
+  it.each([false, true])(
+    "can skip CSS Modules setup for the harness (skip: %s)",
+    async (skipCssModules) => {
+      setupProject(tmpDir, { router: "pages" });
+      writeFile(tmpDir, "pages/index.module.scss", ".redText { color: red }");
+
+      const { result, output } = await runInit(tmpDir, { platform: "node", skipCssModules });
+      const config = readFile(tmpDir, "vite.config.ts");
+
+      expect(config.includes("patchCssModules")).toBe(!skipCssModules);
+      expect(config.includes("generateScopedName")).toBe(!skipCssModules);
+      expect(result.installedDeps.includes("vite-css-modules")).toBe(!skipCssModules);
+      expect(result.installedDeps.includes("postcss")).toBe(!skipCssModules);
+      expect(output.includes("Configured vite-css-modules")).toBe(!skipCssModules);
+      expect(config).toContain("vinext()");
+    },
+  );
+
   it("finds CSS, Sass, and hidden source modules without scanning dependencies or output", () => {
     writeFile(tmpDir, "node_modules/lib/ignored.module.css", "");
     writeFile(tmpDir, "dist/ignored.module.scss", "");