fix(client): load plugin bundles as external scripts

2026-08-04 14:15:32 +08:00
parent 64f9a83bd6
commit 6c6d933732
26 changed files with 252 additions and 159 deletions
--- a/packages/client/modules/README.i18n.yaml
+++ b/packages/client/modules/README.i18n.yaml
@@ -2,5 +2,5 @@
 # side as of the last confirmed-consistent state. Both languages carry equal authority;
 # after editing either side, bring the other along and re-record with:
 #   pnpm run verify-translation-pairing --write packages/client/modules/README.md
-README.md: 99565b349d782c58752ac3e73ce7c0be527f78a8
-README.zh.md: a8ed0a4949ccefce53933b4f2fb8f51f5291684f
+README.md: 7d661c806955d0fac021dd6620994aab83c0f773
+README.zh.md: a1da42a552dbe8770fcb78bf458c01a0057ce8dd
--- a/packages/client/modules/README.md
+++ b/packages/client/modules/README.md
@@ -6,9 +6,9 @@ Client module system: the browser peer of Node's internal ESM loader, built as a

 Lazy CJS model (web2): executing a plugin bundle only REGISTERS its factory (`window.__ModuleLoader__.load({id, factory})`); every module body side effect — CSS injection included — lives in the factory closure and runs at materialization (`factory(require)` → export surface, memoized in `loadCache`), not at script execution. A factory that requires another registered-but-unmaterialized module materializes it recursively, so load order needs no external sequencing; require cycles throw (factory-form CJS cannot deliver partial exports). `<id>/client` and the bare id name the same surface (a plugin bundle IS its package's client half).

-Resolution branch order (`import(specifier)`): platform seed word → shell instance; memoized record → surface; shell-own static registry (`registerStatic`, app-shell) → module; registered factory → materialize; graph row (`window.__DSH_BOOT__`) → fetch + execute + materialize; anything else throws — the runtime mirror of the build-time bundle purity gate. The synchronous `require` handed to factories walks the same order minus the fetch branch and records observed edges into the module record. `prefetch` is the stage-one arrival hook (fetch + execute, registration only; concurrent calls share one in-flight task); `invalidate` drops the factory and the materialized record so the next prefetch/import refetches (the HMR hook).
+Resolution branch order (`import(specifier)`): platform seed word → shell instance; memoized record → surface; shell-own static registry (`registerStatic`, app-shell) → module; registered factory → materialize; graph row (`window.__DSH_BOOT__`) → load its external classic script + materialize; anything else throws — the runtime mirror of the build-time bundle purity gate. The synchronous `require` handed to factories walks the same order minus the asynchronous load branch and records observed edges into the module record. `prefetch` is the stage-one arrival hook (script load and factory registration only; concurrent calls share one in-flight task); `invalidate` drops the factory and materialized record so the next prefetch/import reloads the script (the HMR hook).

-The Node half scans enabled Loader entries for web `dshClient` packages, resolves each `exports["./client"]`, hashes the built bundle into the boot graph, and serves it under `/plugins`. Source launch maps host imports to TypeScript source but still consumes this built client export; missing files share one build instruction followed by a package/path list, while unrelated filesystem errors remain separate failures.
+The Node half scans enabled Loader entries for web `dshClient` packages, resolves each `exports["./client"]`, hashes the built bundle into the boot graph, and serves it with its source map under `/plugins`. Source launch maps host imports to TypeScript source but still consumes this built client export; missing files share one build instruction followed by a package/path list, while unrelated filesystem errors remain separate failures.

 ## Model Experience

--- a/packages/client/modules/README.zh.md
+++ b/packages/client/modules/README.zh.md
@@ -6,9 +6,9 @@

 惰性 CJS 模型（web2）：执行插件组合包只会注册其 factory（`window.__ModuleLoader__.load({id, factory})`）；每个模块主体的副作用（包括 CSS 注入）都位于 factory 闭包中，在物化时运行（`factory(require)` → 导出表层，并在 `loadCache` 中记忆化），不会在脚本执行时运行。如果 factory 依赖另一个已注册但尚未物化的模块，系统会递归物化它，因此加载顺序无需外部编排；require 循环会抛出异常（factory 形式的 CJS 无法提供部分导出）。`<id>/client` 与裸 id 指向同一表层（一个插件组合包就是其包的客户端侧）。

-解析分支顺序（`import(specifier)`）：平台种子词 → 外壳实例；记忆化记录 → 表层；外壳自身的静态注册表（`registerStatic`，app-shell）→ 模块；已注册 factory → 物化；模块图记录（`window.__DSH_BOOT__`）→ 抓取 + 执行 + 物化；其他情况一律抛出异常。这是构建时组合包纯度门禁的运行时镜像。交给 factory 的同步 `require` 采用相同顺序，但不含抓取分支，并把观察到的边记录到模块记录中。`prefetch` 是第一阶段加载钩子（抓取 + 执行，只注册；并发调用共享一个进行中的任务）；`invalidate` 会丢弃 factory 与物化记录，使下一次 prefetch/import 重新抓取；它是 HMR（热模块替换）钩子。
+解析分支顺序（`import(specifier)`）：平台种子词 → 外壳实例；记忆化记录 → 表层；外壳自身的静态注册表（`registerStatic`，app-shell）→ 模块；已注册 factory → 物化；模块图记录（`window.__DSH_BOOT__`）→ 加载外部 classic script + 物化；其他情况一律抛出异常。这是构建时组合包纯度门禁的运行时镜像。交给 factory 的同步 `require` 采用相同顺序，但不含异步加载分支，并把观察到的边记录到模块记录中。`prefetch` 是第一阶段到达钩子（只加载脚本并注册 factory；并发调用共享一个进行中的任务）；`invalidate` 会丢弃 factory 与物化记录，使下一次 prefetch/import 重新加载脚本；它是 HMR（热模块替换）钩子。

-Node 侧会扫描已启用的 Loader 配置项以发现 web `dshClient` 包，解析每个 `exports["./client"]`，把构建后的组合包哈希写入启动图，并通过 `/plugins` 提供该文件。源码启动会把宿主侧导入映射到 TypeScript 源码，但仍消费客户端导出的构建产物；缺失文件共享一条构建要求，随后以 package/path list 列出各项，而无关的文件系统错误仍是独立故障。
+Node 侧会扫描已启用的 Loader 配置项以发现 web `dshClient` 包，解析每个 `exports["./client"]`，把构建后的组合包哈希写入启动图，并通过 `/plugins` 提供该文件及其 sourcemap。源码启动会把宿主侧导入映射到 TypeScript 源码，但仍消费客户端导出的构建产物；缺失文件共享一条构建要求，随后以 package/path list 列出各项，而无关的文件系统错误仍是独立故障。

 ## 模型体验

--- a/packages/client/modules/src/client/manifest.ts
+++ b/packages/client/modules/src/client/manifest.ts
@@ -17,11 +17,11 @@
 *
 * Resolution branch order (import): seed word → shell instance; memoized
 * record → surface; static registry (shell-own modules, e.g. app-shell) →
- * module; registered factory → materialize; graph row → fetch + execute +
- * materialize; anything else → throw (loud — the runtime mirror of the
+ * module; registered factory → materialize; graph row → load + materialize;
+ * anything else → throw (loud — the runtime mirror of the
 * build-time bundle purity gate). The synchronous `require` handed to
- * factories walks the same order minus the fetch branch: fetching is async,
- * so only already-executed bundles can be required — and cross-plugin value
+ * factories walks the same order minus the load branch: loading is async,
+ * so only already-registered bundles can be required — and cross-plugin value
 * imports are a build error anyway.
 *
 * This file is the browser-safe contract face (zero node imports): the
@@ -56,7 +56,7 @@ export interface WebBootEntry {
  rev: string
  /** Package-name dependency edges, informational (preflight display / HMR diffing). */
  inject?: string[]
-  /** Stage-one prefetch mark: fetch + execute (factory registration) during module-face boot. */
+  /** Stage-one prefetch mark: load the script for factory registration during module-face boot. */
  immediately?: boolean
 }

@@ -210,18 +210,17 @@ export interface ClientModuleLoader {
   */
  registerStatic(id: string, module: unknown): void
  /**
-   * Stage-one arrival: fetch the entry's bundle and execute it, registering
-   * its factory (no materialization — module side effects wait for import).
+   * Stage-one arrival: load the entry's script to register its factory (no
+   * materialization — module side effects wait for import).
   * No-op for static-registered ids and ids whose factory is already
   * registered; concurrent calls share one in-flight task. To force a fresh
-   * fetch (HMR), {@link invalidate} first.
+   * load (HMR), {@link invalidate} first.
   * @param id - graph entry name.
   */
  prefetch(id: string): Promise<void>
  /**
-   * Full reset of one module: drop its registered factory, its materialized
-   * record, and any consumed bundle text, so the next prefetch/import
-   * refetches and re-executes (the HMR invalidation hook).
+   * Full reset of one module: drop its registered factory and materialized
+   * record so the next prefetch/import reloads it (the HMR invalidation hook).
   * @param id - entry name to invalidate.
   */
  invalidate(id: string): void
@@ -233,11 +232,6 @@ export interface ClientModuleSystemOptions {
  modules: BootModuleRow[]
  /** Module-table seed: platform-singleton specifier → shell instance. */
  staticModules: Record<string, unknown>
-  /** Bundle fetch seam (parallelizable half). Defaults to same-origin fetch().text(). */
-  fetchBundle?: (url: string) => Promise<string>
-  /**
-   * Bundle execution seam (synchronously performs the load() registration).
-   * Defaults to a <script> element carrying the code.
-   */
-  executeBundle?: (code: string, url: string) => void
+  /** Bundle-load seam. Defaults to a same-origin classic `<script src>` element. */
+  loadBundle?: (url: string) => Promise<void>
 }
--- a/packages/client/modules/src/client/system.ts
+++ b/packages/client/modules/src/client/system.ts
@@ -2,38 +2,28 @@
 * ClientModuleSystem — the implementation behind the {@link ClientModuleLoader}
 * seam. The conceptual contract (lazy CJS model, resolution branch order) is
 * documented on the public interfaces in `./manifest.ts`; this file owns the
- * state tables and the fetch/execute/materialize machinery.
+ * state tables and the load/materialize machinery.
 */
 import type {
  BootModuleRow, ClientModuleLoader, ClientModuleRecord,
  ClientModuleSystemOptions, ClientPluginHandoff, DshWindow,
 } from './manifest.ts'

-/** A registered-but-unmaterialized bundle: the factory plus its source URL (diagnostics). */
-interface RegisteredFactory {
-  factory: ClientPluginHandoff['factory']
-  url: string
-}
-
-/** Default bundle fetch seam: same-origin fetch().text(). */
-const defaultFetchBundle = async (url: string): Promise<string> => {
-  const res = await fetch(url)
-  if (!res.ok) throw new Error(`client-modules: bundle fetch ${url} answered ${String(res.status)}`)
-  return res.text()
-}
-
-/** Default bundle execution seam: a <script> element carrying the code. */
-const defaultExecuteBundle = (code: string, url: string): void => {
+/** Default bundle-load seam: same-origin external classic script. */
+const defaultLoadBundle = (url: string): Promise<void> => new Promise((resolve, reject) => {
  const el = document.createElement('script')
-  // Inline execution (not src) so the fetch half stays parallelizable; the
-  // sourceURL comment keeps devtools stack frames attributed to the bundle.
-  el.textContent = `${code}\n//# sourceURL=${url}`
-  document.head.appendChild(el)
-  // Execution is synchronous for inline scripts: the factory is registered by
-  // now, so the node (and its source text) has no further job. Removing it
-  // keeps repeated HMR rebuilds from accumulating dead script nodes.
-  el.remove()
-}
+  el.async = true
+  el.src = url
+  el.addEventListener('load', () => {
+    el.remove()
+    resolve()
+  }, { once: true })
+  el.addEventListener('error', () => {
+    el.remove()
+    reject(new Error(`client-modules: bundle script ${url} failed to load`))
+  }, { once: true })
+  document.head.append(el)
+})

 /**
 * A plugin bundle IS its package's client half: `<id>/client` (the exports
@@ -72,31 +62,21 @@ export class ClientModuleSystem implements ClientModuleLoader {

  private readonly seed: Map<string, unknown>
  private readonly statics = new Map<string, unknown>()
-  private readonly factories = new Map<string, RegisteredFactory>()
-  /** In-flight prefetch (fetch + execute) per id; concurrent callers share it. */
+  private readonly factories = new Map<string, ClientPluginHandoff['factory']>()
+  /** In-flight prefetch (script load) per id; concurrent callers share it. */
  private readonly pendingArrival = new Map<string, Promise<void>>()
  /** Materialization re-entrancy guard: factory-form CJS cannot deliver partial exports, so a cycle is fatal. */
  private readonly materializing = new Set<string>()
  private readonly graphRows = new Map<string, BootModuleRow>()
-  // Execution URL of the bundle currently being executed (bound into the
-  // factory registration so diagnostics can name the source).
-  private executingUrl = ''
-  // Graph id of the row currently being executed ('' outside arrive):
-  // the load sink cross-checks the handoff id against it so a mis-stamped
-  // bundle cannot register under another entry's identity.
-  private executingId = ''
-
-  private readonly fetchBundle: (url: string) => Promise<string>
-  private readonly executeBundle: (code: string, url: string) => void
+  private readonly loadBundle: (url: string) => Promise<void>

  /**
   * Build the module system over the parsed boot rows.
-   * @param options - module rows, module-table staticModules, fetch/execute seams.
+   * @param options - module rows, module-table staticModules, and bundle-load seam.
   */
  constructor(options: ClientModuleSystemOptions) {
    this.seed = new Map(Object.entries(options.staticModules))
-    this.fetchBundle = options.fetchBundle ?? defaultFetchBundle
-    this.executeBundle = options.executeBundle ?? defaultExecuteBundle
+    this.loadBundle = options.loadBundle ?? defaultLoadBundle

    for (const row of options.modules) {
      if (this.graphRows.has(row.id)) throw new Error(`client-modules: duplicate graph entry "${row.id}"`)
@@ -110,37 +90,22 @@ export class ClientModuleSystem implements ClientModuleLoader {
        // Registration is keyed by the handoff id; a duplicate means a bundle
        // executed twice without an invalidate — always a bug, always loud.
        if (this.factories.has(handoff.id)) throw new Error(`client-modules: duplicate factory registration for "${handoff.id}" (bundle executed twice without invalidate?)`)
-        // A fetched row's bundle must register the id its row names — a
-        // mis-stamped bundle registering under another entry's identity
-        // would let that entry silently materialize foreign exports.
-        if (this.executingId !== '' && handoff.id !== this.executingId) {
-          throw new Error(`client-modules: bundle ${this.executingUrl} registered "${handoff.id}" while arriving for "${this.executingId}" (mis-stamped bundle id)`)
-        }
-        this.factories.set(handoff.id, { factory: handoff.factory, url: this.executingUrl })
+        this.factories.set(handoff.id, handoff.factory)
      },
    }
  }

-  /** Fetch + execute one graph row so its factory is registered (idempotent per in-flight arrival). */
+  /** Load one graph row so its factory is registered (idempotent per in-flight arrival). */
  private arrive(row: BootModuleRow): Promise<void> {
    const { id, url } = row
    const pending = this.pendingArrival.get(id)
    if (pending !== undefined) return pending
    if (this.factories.has(id)) return Promise.resolve()
-    const task = (async (): Promise<void> => {
-      const code = await this.fetchBundle(url)
-      this.executingUrl = url
-      this.executingId = id
-      try {
-        this.executeBundle(code, url)
-      } finally {
-        this.executingUrl = ''
-        this.executingId = ''
-      }
+    const task = this.loadBundle(url).then(() => {
      if (!this.factories.has(id)) {
-        throw new Error(`client-modules: bundle ${url} executed without registering "${id}" via __ModuleLoader__.load`)
+        throw new Error(`client-modules: bundle ${url} loaded without registering "${id}" via __ModuleLoader__.load`)
      }
-    })().finally(() => { this.pendingArrival.delete(id) })
+    }).finally(() => { this.pendingArrival.delete(id) })
    this.pendingArrival.set(id, task)
    return task
  }
@@ -158,7 +123,7 @@ export class ClientModuleSystem implements ClientModuleLoader {
    this.materializing.add(id)
    try {
      const edges = new Set<string>()
-      const surface = registered.factory(this.makeRequire(edges))
+      const surface = registered(this.makeRequire(edges))
      const record: ClientModuleRecord = { id, surface, styles: claimStyles(id), edges }
      this.loadCache.set(id, record)
      return record
--- a/packages/client/modules/src/index.ts
+++ b/packages/client/modules/src/index.ts
@@ -2,8 +2,8 @@
 * Node half of the client module system (dshClient dual-face package): scans
 * the host Loader's entries for `dshClient` packages, composes the
 * `window.__DSH_BOOT__` entry graph (wire single source: {@link WebBootEntry}
- * in `./client/manifest.ts`), serves `/plugins/<id>/client.js`, taps the
- * index render to inject the boot manifest, and provides the
+ * in `./client/manifest.ts`), serves `/plugins/<id>/client.js` and its source
+ * map, taps the index render to inject the boot manifest, and provides the
 * `clientModuleHost` service (the HMR node half's registration/notification
 * face).
 *
@@ -424,9 +424,15 @@ export class ClientModuleHostService extends Service {
    const pathname = decodeURIComponent(new URL(req.url ?? '/', 'http://x').pathname)
    // The id may contain a scope slash. Anything else under /plugins (including
    // /plugins/events when the HMR row is absent) is an unknown resource.
-    const path = pathname.startsWith('/plugins/') && pathname.endsWith('/client.js')
-      ? this.clientPath(pathname.slice('/plugins/'.length, -'/client.js'.length))
+    const prefix = '/plugins/'
+    const mapSuffix = '/client.js.map'
+    const bundleSuffix = '/client.js'
+    const isSourceMap = pathname.startsWith(prefix) && pathname.endsWith(mapSuffix)
+    const suffix = isSourceMap ? mapSuffix : bundleSuffix
+    const clientPath = pathname.startsWith(prefix) && pathname.endsWith(suffix)
+      ? this.clientPath(pathname.slice(prefix.length, -suffix.length))
      : undefined
+    const path = clientPath === undefined ? undefined : `${clientPath}${isSourceMap ? '.map' : ''}`
    if (path === undefined) {
      res.writeHead(404)
      res.end()
@@ -434,7 +440,10 @@ export class ClientModuleHostService extends Service {
    }
    try {
      const body = await readFile(path)
-      res.writeHead(200, { 'content-type': 'text/javascript; charset=utf-8', 'cache-control': 'no-cache' })
+      res.writeHead(200, {
+        'content-type': isSourceMap ? 'application/json; charset=utf-8' : 'text/javascript; charset=utf-8',
+        'cache-control': 'no-cache',
+      })
      res.end(body)
    } catch {
      // Registered but unreadable (bundle not built yet): loud 404 beats a silent SPA-fallback HTML page.
--- a/packages/client/modules/tests/loader.spec.ts
+++ b/packages/client/modules/tests/loader.spec.ts
@@ -4,7 +4,7 @@
 * registers the factory), materialization on first import/require with
 * memoization and recursive self-sequencing, the resolution branch order,
 * shared in-flight arrival, invalidate-refetch (HMR), style claiming, the
- * default transport seams, and the loud failure modes (duplicate
+ * default transport seam, and the loud failure modes (duplicate
 * registration, cycles, table misses, double boot).
 */
 import { afterEach, describe, expect, it, vi } from 'vitest'
@@ -20,7 +20,6 @@ type Factory = ClientPluginHandoff['factory']
 afterEach(() => {
  vi.unstubAllGlobals()
  delete win.__ModuleLoader__
-  delete (document as unknown as Record<string, unknown>).__realmBridge
  for (const el of document.querySelectorAll('style, script')) el.remove()
 })

@@ -33,9 +32,9 @@ interface Bench {
 }

 /**
- * Loader over scripted bundles: fetch resolves to the row url (optionally
- * gated on a release callback); execute registers the scripted factory
- * through the window sink (`null` scripts a bundle that never calls load).
+ * Loader over scripted bundles: load records the row URL, optionally waits on
+ * a release callback, then registers the scripted factory through the window
+ * sink (`null` scripts a bundle that never calls load).
 */
 function bench(
  entries: BootModuleRow[],
@@ -47,15 +46,12 @@ function bench(
  const loader = new ClientModuleSystem({
    modules: entries,
    staticModules: opts.seed ?? {},
-    fetchBundle: (url) => {
+    loadBundle: async (url) => {
      fetched.push(url)
      if (opts.gated?.includes(url) === true) {
-        return new Promise((resolve) => { gates.set(url, () => { resolve(url) }) })
+        await new Promise<void>((resolve) => { gates.set(url, resolve) })
      }
-      return Promise.resolve(url)
-    },
-    executeBundle: (code) => {
-      const id = /\/plugins\/(.+)\/client\.js/.exec(code)?.[1]
+      const id = /\/plugins\/(.+)\/client\.js/.exec(url)?.[1]
      const factory = id === undefined ? undefined : bundles[id]
      if (factory == null || id === undefined) return
      win.__ModuleLoader__?.load({ id, factory })
@@ -65,7 +61,7 @@ function bench(
 }

 describe('lazy CJS arrival', () => {
-  it('prefetch fetches and executes but does not run the factory', async () => {
+  it('prefetch loads and registers but does not run the factory', async () => {
    const ran: string[] = []
    const b = bench([row('a')], { a: () => { ran.push('a'); return {} } })
    await b.loader.prefetch('a')
@@ -85,7 +81,7 @@ describe('lazy CJS arrival', () => {
    expect(b.loader.loadCache.get('a')?.id).toBe('a')
  })

-  it('import without prefetch fetches, executes, and materializes in one call', async () => {
+  it('import without prefetch loads, registers, and materializes in one call', async () => {
    const b = bench([row('a')], { a: () => ({ marker: 'direct' }) })
    const surface = await b.loader.import('a', '', {})
    expect((surface as { marker: string }).marker).toBe('direct')
@@ -228,7 +224,7 @@ describe('failure modes', () => {
 })

 describe('HMR reset', () => {
-  it('invalidate drops the factory and record so the module refetches and re-registers', async () => {
+  it('invalidate drops the factory and record so the module reloads and re-registers', async () => {
    let generation = 0
    const b = bench([row('a')], { a: () => ({ generation: ++generation }) })
    const first = await b.loader.import('a', '', {})
@@ -275,27 +271,35 @@ describe('style claiming', () => {
  })
 })

-describe('default transport seams', () => {
-  it('fetches same-origin and executes through an inline script tag', async () => {
-    // In a browser the loader's globalThis IS the page window; vitest's jsdom
-    // evaluates <script> in a separate realm that shares only the document,
-    // so the fixture bundle restores the sink from a document bridge before
-    // using the normal calling convention.
-    const code = 'window.__ModuleLoader__ = document.__realmBridge;\n'
-      + 'window.__ModuleLoader__.load({ id: "dee", factory: function () { return { marker: "via-script" } } })'
-    vi.stubGlobal('fetch', async () => ({ ok: true, text: async () => code }))
+describe('default transport seam', () => {
+  it('loads through an external classic script and removes the settled node', async () => {
+    const append = vi.spyOn(document.head, 'append').mockImplementation((...nodes) => {
+      const script = nodes[0]
+      if (!(script instanceof HTMLScriptElement)) throw new Error('expected script node')
+      expect(script.async).toBe(true)
+      expect(script.getAttribute('src')).toBe('/plugins/dee/client.js?rev=0')
+      queueMicrotask(() => {
+        win.__ModuleLoader__?.load({ id: 'dee', factory: () => ({ marker: 'via-script' }) })
+        script.dispatchEvent(new Event('load'))
+      })
+    })
    const loader: ClientModuleLoader = new ClientModuleSystem({ modules: [row('dee')], staticModules: {} })
-    ;(document as unknown as Record<string, unknown>).__realmBridge = win.__ModuleLoader__
    const surface = await loader.import('dee', '', {})
    expect((surface as { marker: string }).marker).toBe('via-script')
-    // The script node is removed right after its synchronous execution —
-    // repeated HMR rebuilds must not accumulate dead script nodes.
+    expect(append).toHaveBeenCalledOnce()
    expect([...document.querySelectorAll('script')]).toEqual([])
  })

-  it('a non-ok bundle response is loud with the status', async () => {
-    vi.stubGlobal('fetch', async () => ({ ok: false, status: 404 }))
+  it('a script load failure is loud and removes the node', async () => {
+    vi.spyOn(document.head, 'append').mockImplementation((...nodes) => {
+      const script = nodes[0]
+      if (!(script instanceof HTMLScriptElement)) throw new Error('expected script node')
+      queueMicrotask(() => { script.dispatchEvent(new Event('error')) })
+    })
    const loader = new ClientModuleSystem({ modules: [row('dee')], staticModules: {} })
-    await expect(loader.prefetch('dee')).rejects.toThrow('answered 404')
+    await expect(loader.prefetch('dee')).rejects.toThrow(
+      'bundle script /plugins/dee/client.js?rev=0 failed to load',
+    )
+    expect([...document.querySelectorAll('script')]).toEqual([])
  })
 })
--- a/packages/client/modules/tests/node-half.spec.ts
+++ b/packages/client/modules/tests/node-half.spec.ts
@@ -1,12 +1,13 @@
 /** Node-half composition diagnostics for package metadata and built client bundles. */

 import { mkdirSync, mkdtempSync, realpathSync, rmSync, writeFileSync } from 'node:fs'
+import type { IncomingMessage, ServerResponse } from 'node:http'
 import { tmpdir } from 'node:os'
-import { join } from 'node:path'
+import { dirname, join } from 'node:path'
 import { pathToFileURL } from 'node:url'
 import { Context } from 'cordis'
 import { afterEach, describe, expect, it } from 'vitest'
-import type { HttpServerService } from '@deepseek-ai/dsh-host-webserver'
+import type { HttpServerService, WebRoute } from '@deepseek-ai/dsh-host-webserver'
 import { ClientModuleHostService } from '../src/index.ts'

 let root: string | undefined
@@ -33,8 +34,8 @@ function writePackage(packageName: string): string {
  return clientPath
 }

-/** Construct the node-half service over the enabled fixture entries. */
-function construct(packageNames: string[]): ClientModuleHostService {
+/** Construct the node-half service and capture its plugin-bundle route. */
+function constructWithRoute(packageNames: string[]): { service: ClientModuleHostService; route: WebRoute } {
  const ctx = new Context()
  ctx.baseUrl = pathToFileURL(root!).href + '/'
  ctx.provide('loader', {
@@ -44,13 +45,24 @@ function construct(packageNames: string[]): ClientModuleHostService {
      }
    },
  })
+  let route: WebRoute | undefined
  const httpServer: Pick<HttpServerService, 'port' | 'register' | 'tapIndex'> = {
    port: 0,
-    register: () => () => {},
+    register: (candidate) => {
+      if (candidate.path === '/plugins') route = candidate
+      return () => {}
+    },
    tapIndex: () => () => {},
  }
  ctx.provide('httpServer', httpServer as HttpServerService)
-  return new ClientModuleHostService(ctx)
+  const service = new ClientModuleHostService(ctx)
+  if (route === undefined) throw new Error('client bundle route was not registered')
+  return { service, route }
+}
+
+/** Construct the node-half service over the enabled fixture entries. */
+function construct(packageNames: string[]): ClientModuleHostService {
+  return constructWithRoute(packageNames).service
 }

 describe('client bundle activation', () => {
@@ -84,4 +96,40 @@ describe('client bundle activation', () => {
    expect(String(thrown)).toContain('EISDIR')
    expect(String(thrown)).not.toContain('pnpm run build')
  })
+
+  it('serves the source map beside a registered client bundle', async () => {
+    const packageName = '@fixture/source-map'
+    const clientPath = writePackage(packageName)
+    mkdirSync(dirname(clientPath), { recursive: true })
+    writeFileSync(clientPath, 'module.exports = {}\n')
+    const map = '{"version":3,"sources":["src/client/index.tsx"]}\n'
+    writeFileSync(`${clientPath}.map`, map)
+    const { route } = constructWithRoute([packageName])
+    let status = 0
+    let headers: Record<string, string> | undefined
+    let body = ''
+    const response = {
+      writeHead(nextStatus: number, nextHeaders?: Record<string, string>) {
+        status = nextStatus
+        headers = nextHeaders
+        return response
+      },
+      end(chunk?: Uint8Array) {
+        body = chunk === undefined ? '' : Buffer.from(chunk).toString('utf8')
+        return response
+      },
+    } as unknown as ServerResponse
+
+    await route.handler({
+      method: 'GET',
+      url: `/plugins/${packageName}/client.js.map`,
+    } as IncomingMessage, response)
+
+    expect(status).toBe(200)
+    expect(headers).toEqual({
+      'content-type': 'application/json; charset=utf-8',
+      'cache-control': 'no-cache',
+    })
+    expect(body).toBe(map)
+  })
 })