fix(optimize-deps): ignore ERR_CLOSED_SERVER in scanner

packages/vite/src/node/__tests__/scan.spec.ts

@@ -256,6 +256,35 @@ test('scan resolves build.rolldownOptions.input relative to the root', async (ct
   })
 })
 
+// regression test for `The server is being restarted or closed. Request is outdated`
+// error in the scanner. The dependency scanner runs in the background and
+// may still be crawling when the server is closed. The scan fails because resolutions
+// reject with `ERR_CLOSED_SERVER`, but this failure must be ignored (the scan result is
+// discarded on close anyway) so it doesn't escape as an unhandled rejection.
+test('scan ignores the failure when the server is closed mid-scan', async (ctx) => {
+  const server = await createServer({
+    configFile: false,
+    logLevel: 'silent',
+    root: path.join(import.meta.dirname, 'fixtures', 'scan-build-input', 'src'),
+    optimizeDeps: {
+      entries: ['./entry-client.tsx'],
+      force: true,
+      noDiscovery: false,
+    },
+  })
+  ctx.onTestFinished(() => server.close())
+
+  // Simulate the server being torn down while the scanner is still running.
+  await server.environments.client.pluginContainer.close()
+
+  const { cancel, result } = scanImports(
+    devToScanEnvironment(server.environments.client),
+  )
+  ctx.onTestFinished(cancel)
+
+  await expect(result).resolves.toEqual({ deps: {}, missing: {} })
+})
+
 test('scan import.meta.glob package imports patterns', async (ctx) => {
   const server = await createServer({
     configFile: false,

packages/vite/src/node/optimizer/scan.ts

@@ -32,7 +32,10 @@ import {
   virtualModuleRE,
 } from '../utils'
 import type { EnvironmentPluginContainer } from '../server/pluginContainer'
-import { createEnvironmentPluginContainer } from '../server/pluginContainer'
+import {
+  ERR_CLOSED_SERVER,
+  createEnvironmentPluginContainer,
+} from '../server/pluginContainer'
 import { BaseEnvironment } from '../baseEnvironment'
 import type { DevEnvironment } from '../server/environment'
 import { transformGlobImport } from '../plugins/importMetaGlob'
@@ -165,6 +168,17 @@ export function scanImports(environment: ScanEnvironment): {
         missing,
       }
     } catch (e) {
+      // The scanner runs in the background and may still be crawling when the
+      // server is closed. In that case resolutions reject with
+      // `ERR_CLOSED_SERVER` and the scan build fails.
+      if (
+        e.errors?.some(
+          (error: { pluginCode?: string }) =>
+            error.pluginCode === ERR_CLOSED_SERVER,
+        )
+      ) {
+        return
+      }
       const prependMessage = colors.red(`\
   Failed to scan for dependencies from entries:
   ${entries.join('\n')}