test(rsc): fail fast when fixture server exits

packages/plugin-rsc/AGENTS.md

@@ -11,12 +11,21 @@ Before creating or changing a conventional RSC example, use [`examples/starter-e
 
 ## Quick Reference for AI Agents
 
-### Essential Commands
+### Fresh Worktree Setup
 
 ```bash
-# inside packages/plugin-rsc directory
-pnpm build                          # build package
+# from the repository root
+pnpm install
+pnpm build
+```
+
+Run the full workspace build before RSC E2E tests because examples use other workspace packages, such as `@vitejs/plugin-react`.
+
+### Package Commands
+
+```bash
+# inside packages/plugin-rsc
 pnpm tsc                            # typecheck
-pnpm test                           # Run unit tests
-pnpm test-e2e                       # Run e2e tests
+pnpm test --run                     # run unit tests
+pnpm test-e2e                       # run E2E tests
 ```

packages/plugin-rsc/CONTRIBUTING.md

@@ -41,8 +41,12 @@ Use colocated unit tests for self-contained transforms and utilities.
 ## Development Workflow
 
 ```bash
-# Build packages
-pnpm dev # pnpm -C packages/plugin-rsc dev
+# Install and build from the repository root
+pnpm install
+pnpm build
+
+# Watch the RSC package during development
+pnpm -C packages/plugin-rsc dev
 
 # Type check
 pnpm -C packages/plugin-rsc tsc

packages/plugin-rsc/e2e/fixture.ts

@@ -23,7 +23,7 @@ function runCli(options: { command: string; label?: string } & SpawnOptions) {
     console.log(styleText('magenta', label), data.toString())
   })
   const done = new Promise<void>((resolve) => {
-    child.on('exit', (code) => {
+    child.on('close', (code) => {
       if (code !== 0 && code !== 143 && process.platform !== 'win32') {
         console.log(styleText('magenta', `${label}`), `exit code ${code}`)
       }
@@ -32,15 +32,42 @@ function runCli(options: { command: string; label?: string } & SpawnOptions) {
   })
 
   async function findPort(): Promise<number> {
-    let stdout = ''
-    return new Promise((resolve) => {
-      child.stdout!.on('data', (data) => {
-        stdout += stripVTControlCharacters(String(data))
-        const match = stdout.match(/http:\/\/localhost:(\d+)/)
+    let portOutput = ''
+    return new Promise((resolve, reject) => {
+      function cleanup() {
+        child.stdout!.off('data', onData)
+        child.off('close', onClose)
+        child.off('error', onError)
+      }
+
+      function onData(data: Buffer) {
+        portOutput += stripVTControlCharacters(String(data))
+        const match = portOutput.match(/http:\/\/localhost:(\d+)/)
         if (match) {
+          cleanup()
           resolve(Number(match[1]))
         }
-      })
+      }
+
+      function onClose(code: number | null, signal: NodeJS.Signals | null) {
+        cleanup()
+        const details = stderr.trim() || stdout.trim()
+        reject(
+          new Error(
+            `${label} exited with ${code ?? signal ?? 'unknown status'} before publishing a port` +
+              (details ? `\n${details}` : ''),
+          ),
+        )
+      }
+
+      function onError(error: Error) {
+        cleanup()
+        reject(error)
+      }
+
+      child.stdout!.on('data', onData)
+      child.on('close', onClose)
+      child.on('error', onError)
     })
   }