fix(rsc): avoid dev server access during builds

Author: james-elicx

packages/plugin-rsc/src/plugins/server-function-directives.test.ts

@@ -124,6 +124,14 @@ export async function getData() {
     ).toEqual([expect.stringMatching(/^\$\$hoist_/)])
   })
 
+  it('does not require a dev server during build transforms', async () => {
+    const { manager, run } = createHarness([cacheDirective()])
+    manager.server = undefined as unknown as Manager['server']
+    await expect(
+      run(`export async function getData() { "use cache"; return 1 }`),
+    ).resolves.toBeDefined()
+  })
+
   it('encrypts captured values without adding ciphertext to the wrapper', async () => {
     const wrap = vi.fn(({ value }: { value: string }) => `cache(${value})`)
     const { run } = createHarness([cacheDirective({ wrap })])

packages/plugin-rsc/src/plugins/server-function-directives.ts

@@ -176,12 +176,12 @@ export function vitePluginServerFunctionDirectives(options: Options): Plugin {
         const useServerBoundary = hasDirective(ast.body, 'use server')
         if (!isServer && useServerBoundary) return
 
-        const serverEnvironment =
-          manager.server.environments[options.serverEnvironmentName]
         let normalizedId: string
         if (manager.config.command === 'build') {
           normalizedId = hashString(manager.toRelativeId(id))
         } else {
+          const serverEnvironment =
+            manager.server.environments[options.serverEnvironmentName]
           if (!serverEnvironment) {
             throw new Error(
               `Missing ${JSON.stringify(options.serverEnvironmentName)} environment`,