fix: thread Vite base through SSR manifest and Nitro baseURL

packages/start-nitro-v2-vite-plugin/src/index.ts

@@ -13,13 +13,20 @@ import type { PluginOption, Rollup } from "vite";
 
 let ssrBundle: Rollup.OutputBundle;
 let ssrEntryFile: string;
+let viteBase: string = "/";
 
 export type UserNitroConfig = Omit<NitroConfig, "dev" | "publicAssets" | "renderer">;
 
 export function nitroV2Plugin(nitroConfig?: UserNitroConfig): PluginOption {
   return [
     {
       name: "solid-start-vite-plugin-nitro",
+      configResolved(config) {
+        // Capture the resolved Vite base so the Nitro build can default its
+        // baseURL to the same subpath. A user-supplied nitroConfig.baseURL
+        // still wins; this just removes the need to set the same prefix twice.
+        viteBase = config.base ?? "/";
+      },
       generateBundle: {
         handler(_options, bundle) {
           if (this.environment.name !== "ssr") {
@@ -78,6 +85,7 @@ export function nitroV2Plugin(nitroConfig?: UserNitroConfig): PluginOption {
                 compatibilityDate: "2024-11-19",
                 logLevel: 3,
                 preset: "node-server",
+                baseURL: viteBase,
                 typescript: {
                   generateTsConfig: false,
                   generateRuntimeConfigTypes: false,

packages/start/src/server/manifest/dev-client-manifest.ts

@@ -3,7 +3,7 @@ import { join } from "pathe";
 export function getClientDevManifest() {
   return {
     import(id) {
-      return import(/* @vite-ignore */ join("/", id));
+      return import(/* @vite-ignore */ join(import.meta.env.BASE_URL, id));
     },
     async getAssets(id) {
       const assetsPath = `/@manifest/client/${Date.now()}/assets?id=${id}`;

packages/start/src/server/manifest/prod-ssr-manifest.spec.ts

@@ -0,0 +1,110 @@
+import { afterEach, beforeEach, describe, expect, it, vi } from "vitest";
+
+// Fixture: a vite manifest that exposes one entry chunk, one dynamic-entry
+// route chunk with a stylesheet, and one nested import-only chunk.
+const fixtureManifest = {
+  "src/entry-client.tsx": {
+    file: "assets/entry-client-abc.js",
+    isEntry: true,
+    css: ["assets/entry-client-xyz.css"],
+    imports: ["_shared.js"],
+  },
+  "_shared.js": {
+    file: "assets/shared-def.js",
+    css: [],
+  },
+  "src/routes/foo.tsx": {
+    file: "assets/foo-ghi.js",
+    isDynamicEntry: true,
+    css: ["assets/foo-jkl.css"],
+    imports: ["_shared.js"],
+  },
+};
+
+vi.mock("solid-start:client-vite-manifest", () => ({
+  clientViteManifest: fixtureManifest,
+}));
+
+async function loadModule() {
+  // Top-level reads of import.meta.env need to be captured at import time,
+  // so isolate the module cache to pick up the current stubs.
+  vi.resetModules();
+  return await import("./prod-ssr-manifest.ts");
+}
+
+describe("getSsrProdManifest under a deploy base", () => {
+  beforeEach(() => {
+    vi.stubEnv("BASE_URL", "/sub/");
+    vi.stubEnv("START_CLIENT_ENTRY", "./src/entry-client.tsx");
+  });
+
+  afterEach(() => {
+    vi.unstubAllEnvs();
+  });
+
+  it("path(id) returns the asset URL prefixed with BASE_URL", async () => {
+    const { getSsrProdManifest } = await loadModule();
+    const m = getSsrProdManifest();
+
+    expect(m.path("src/entry-client.tsx")).toBe("/sub/assets/entry-client-abc.js");
+  });
+
+  it("path(id) normalizes a leading './' the same as the unprefixed form", async () => {
+    const { getSsrProdManifest } = await loadModule();
+    const m = getSsrProdManifest();
+
+    expect(m.path("./src/entry-client.tsx")).toBe("/sub/assets/entry-client-abc.js");
+  });
+
+  it("getAssets(id) returns asset hrefs prefixed with BASE_URL", async () => {
+    const { getSsrProdManifest } = await loadModule();
+    const m = getSsrProdManifest();
+    const assets = await m.getAssets("src/routes/foo.tsx");
+    const hrefs = assets.map(a => a.attrs.href as string).sort();
+
+    // Every emitted href must sit under the deploy base; none may be
+    // root-absolute at "/assets/...".
+    for (const href of hrefs) {
+      expect(href.startsWith("/sub/")).toBe(true);
+    }
+  });
+
+  it("json() serializes each entry with a base-prefixed output path", async () => {
+    const { getSsrProdManifest } = await loadModule();
+    const m = getSsrProdManifest();
+    const json = await m.json();
+
+    expect(json["src/entry-client.tsx"].output).toBe("/sub/assets/entry-client-abc.js");
+    expect(json["src/routes/foo.tsx"].output).toBe("/sub/assets/foo-ghi.js");
+  });
+});
+
+describe("getSsrProdManifest with BASE_URL = '/' (no subpath)", () => {
+  beforeEach(() => {
+    vi.stubEnv("BASE_URL", "/");
+    vi.stubEnv("START_CLIENT_ENTRY", "./src/entry-client.tsx");
+  });
+
+  afterEach(() => {
+    vi.unstubAllEnvs();
+  });
+
+  it("path(id) returns a root-absolute URL (no '//' prefix)", async () => {
+    const { getSsrProdManifest } = await loadModule();
+    const m = getSsrProdManifest();
+
+    expect(m.path("src/entry-client.tsx")).toBe("/assets/entry-client-abc.js");
+  });
+
+  it("getAssets(id) returns single-slash hrefs", async () => {
+    const { getSsrProdManifest } = await loadModule();
+    const m = getSsrProdManifest();
+    const assets = await m.getAssets("src/routes/foo.tsx");
+
+    for (const a of assets) {
+      const href = a.attrs.href as string;
+      expect(href.startsWith("//")).toBe(false);
+      expect(href.startsWith("/")).toBe(true);
+    }
+  });
+});

packages/start/src/server/manifest/prod-ssr-manifest.ts

@@ -13,7 +13,7 @@ export function getSsrProdManifest() {
       const viteManifestEntry = clientViteManifest[id /*import.meta.env.START_CLIENT_ENTRY*/];
       if (!viteManifestEntry) throw new Error(`No entry found in vite manifest for '${id}'`);
 
-      return join("/", viteManifestEntry.file);
+      return join(import.meta.env.BASE_URL, viteManifestEntry.file);
     },
     async getAssets(id) {
       if (id.startsWith("./")) id = id.slice(2);
@@ -29,7 +29,7 @@ export function getSsrProdManifest() {
 
       for (const entryKey of entryKeys) {
         json[entryKey] = {
-          output: join("/", viteManifest[entryKey]!.file),
+          output: join(import.meta.env.BASE_URL, viteManifest[entryKey]!.file),
           assets: await this.getAssets(entryKey),
         };
       }
@@ -54,7 +54,7 @@ function createHtmlTagsForAssets(assets: string[]) {
     .map<Asset>(asset => ({
       tag: "link",
       attrs: {
-        href: "/" + asset,
+        href: join(import.meta.env.BASE_URL, asset),
         key: asset,
         ...(asset.endsWith(".css") ? { rel: "stylesheet" } : { rel: "modulepreload" }),
       },