From 002af4eb3a9b64e1013a13f23446e21dcca16849 Mon Sep 17 00:00:00 2001
From: Tim Neutkens <tim@timneutkens.nl>
Date: Thu, 14 Dec 2023 13:23:55 +0100
Subject: [PATCH] Add test for importing client components from server actions
 (#59615)

## What?

Adds two tests for server actions returning client components:

- (supported) Importing a server action from a server component. That
server action imports a client component and returns it.
- (not supported yet) Importing a server action from a client component.
The server action imports a client component and returns it.

The second case is not supported yet as it would effectively mean a
compilation loop:

`server` -> `client` -> `server` -> `client`

and if that last client component includes another server action it goes
even further:

`server` -> `client` -> `server` -> `client` -> `server` (and if that
server action includes anothe client component it goes further and
further)


Whereas currently it's only `server` -> `client` -> `server`, so it's
limited to that.

In the future we should be able to support this
server->client->server->client loop in Turbopack specifically because
Turbopack has a single module graph.

Importing the client component in a server action that is defined in the
server compiler (i.e. when created inline or when imported from a server
component) it does work correctly already.

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Closes NEXT-1873
---
 test/e2e/app-dir/actions/app-action.test.ts   | 33 +++++++++++++++++++
 .../action-return-client-component/actions.js |  8 +++++
 .../client-component.js                       |  5 +++
 .../action-return-client-component/form.js    | 16 +++++++++
 .../action-return-client-component/page.js    | 12 +++++++
 .../action-return-client-component/actions.js |  8 +++++
 .../client-component.js                       |  5 +++
 .../action-return-client-component/form.js    | 16 +++++++++
 .../action-return-client-component/page.js    | 11 +++++++
 9 files changed, 114 insertions(+)
 create mode 100644 test/e2e/app-dir/actions/app/client/action-return-client-component/actions.js
 create mode 100644 test/e2e/app-dir/actions/app/client/action-return-client-component/client-component.js
 create mode 100644 test/e2e/app-dir/actions/app/client/action-return-client-component/form.js
 create mode 100644 test/e2e/app-dir/actions/app/client/action-return-client-component/page.js
 create mode 100644 test/e2e/app-dir/actions/app/server/action-return-client-component/actions.js
 create mode 100644 test/e2e/app-dir/actions/app/server/action-return-client-component/client-component.js
 create mode 100644 test/e2e/app-dir/actions/app/server/action-return-client-component/form.js
 create mode 100644 test/e2e/app-dir/actions/app/server/action-return-client-component/page.js

diff --git a/test/e2e/app-dir/actions/app-action.test.ts b/test/e2e/app-dir/actions/app-action.test.ts
index 40b1de3ca1..b4698bf084 100644
--- a/test/e2e/app-dir/actions/app-action.test.ts
+++ b/test/e2e/app-dir/actions/app-action.test.ts
@@ -1081,5 +1081,38 @@ createNextDescribe(
         }
       )
     })
+
+    describe('server actions render client components', () => {
+      describe('server component imported action', () => {
+        it('should support importing client components from actions', async () => {
+          const browser = await next.browser(
+            '/server/action-return-client-component'
+          )
+          expect(
+            await browser
+              .elementByCss('#trigger-component-load')
+              .click()
+              .waitForElementByCss('#client-component')
+              .text()
+          ).toBe('Hello World')
+        })
+      })
+
+      // Server Component -> Client Component -> Server Action (imported from client component) -> Import Client Component is not not supported yet.
+      describe.skip('client component imported action', () => {
+        it('should support importing client components from actions', async () => {
+          const browser = await next.browser(
+            '/client/action-return-client-component'
+          )
+          expect(
+            await browser
+              .elementByCss('#trigger-component-load')
+              .click()
+              .waitForElementByCss('#client-component')
+              .text()
+          ).toBe('Hello World')
+        })
+      })
+    })
   }
 )
diff --git a/test/e2e/app-dir/actions/app/client/action-return-client-component/actions.js b/test/e2e/app-dir/actions/app/client/action-return-client-component/actions.js
new file mode 100644
index 0000000000..20f32bf225
--- /dev/null
+++ b/test/e2e/app-dir/actions/app/client/action-return-client-component/actions.js
@@ -0,0 +1,8 @@
+'use server'
+import { Hello } from './client-component'
+
+export async function getComponent() {
+  return {
+    component: <Hello />,
+  }
+}
diff --git a/test/e2e/app-dir/actions/app/client/action-return-client-component/client-component.js b/test/e2e/app-dir/actions/app/client/action-return-client-component/client-component.js
new file mode 100644
index 0000000000..1eb8f26333
--- /dev/null
+++ b/test/e2e/app-dir/actions/app/client/action-return-client-component/client-component.js
@@ -0,0 +1,5 @@
+'use client'
+
+export function Hello() {
+  return <p id="client-component">Hello World</p>
+}
diff --git a/test/e2e/app-dir/actions/app/client/action-return-client-component/form.js b/test/e2e/app-dir/actions/app/client/action-return-client-component/form.js
new file mode 100644
index 0000000000..a37de24565
--- /dev/null
+++ b/test/e2e/app-dir/actions/app/client/action-return-client-component/form.js
@@ -0,0 +1,16 @@
+'use client'
+import { useFormState } from 'react-dom'
+
+export function Form({ action }) {
+  const [state, formAction] = useFormState(action, null)
+  return (
+    <>
+      <form action={formAction}>
+        <button id="trigger-component-load" type="submit">
+          Trigger Component Load
+        </button>
+      </form>
+      {state?.component}
+    </>
+  )
+}
diff --git a/test/e2e/app-dir/actions/app/client/action-return-client-component/page.js b/test/e2e/app-dir/actions/app/client/action-return-client-component/page.js
new file mode 100644
index 0000000000..ae5cfe7630
--- /dev/null
+++ b/test/e2e/app-dir/actions/app/client/action-return-client-component/page.js
@@ -0,0 +1,12 @@
+'use client'
+import { getComponent } from './actions'
+import { Form } from './form'
+
+export default function Page() {
+  return (
+    <>
+      <h1>Server Component loading client component through action</h1>
+      <Form action={getComponent} />
+    </>
+  )
+}
diff --git a/test/e2e/app-dir/actions/app/server/action-return-client-component/actions.js b/test/e2e/app-dir/actions/app/server/action-return-client-component/actions.js
new file mode 100644
index 0000000000..20f32bf225
--- /dev/null
+++ b/test/e2e/app-dir/actions/app/server/action-return-client-component/actions.js
@@ -0,0 +1,8 @@
+'use server'
+import { Hello } from './client-component'
+
+export async function getComponent() {
+  return {
+    component: <Hello />,
+  }
+}
diff --git a/test/e2e/app-dir/actions/app/server/action-return-client-component/client-component.js b/test/e2e/app-dir/actions/app/server/action-return-client-component/client-component.js
new file mode 100644
index 0000000000..1eb8f26333
--- /dev/null
+++ b/test/e2e/app-dir/actions/app/server/action-return-client-component/client-component.js
@@ -0,0 +1,5 @@
+'use client'
+
+export function Hello() {
+  return <p id="client-component">Hello World</p>
+}
diff --git a/test/e2e/app-dir/actions/app/server/action-return-client-component/form.js b/test/e2e/app-dir/actions/app/server/action-return-client-component/form.js
new file mode 100644
index 0000000000..a37de24565
--- /dev/null
+++ b/test/e2e/app-dir/actions/app/server/action-return-client-component/form.js
@@ -0,0 +1,16 @@
+'use client'
+import { useFormState } from 'react-dom'
+
+export function Form({ action }) {
+  const [state, formAction] = useFormState(action, null)
+  return (
+    <>
+      <form action={formAction}>
+        <button id="trigger-component-load" type="submit">
+          Trigger Component Load
+        </button>
+      </form>
+      {state?.component}
+    </>
+  )
+}
diff --git a/test/e2e/app-dir/actions/app/server/action-return-client-component/page.js b/test/e2e/app-dir/actions/app/server/action-return-client-component/page.js
new file mode 100644
index 0000000000..bbbd568968
--- /dev/null
+++ b/test/e2e/app-dir/actions/app/server/action-return-client-component/page.js
@@ -0,0 +1,11 @@
+import { getComponent } from './actions'
+import { Form } from './form'
+
+export default function Page() {
+  return (
+    <>
+      <h1>Server Component loading client component through action</h1>
+      <Form action={getComponent} />
+    </>
+  )
+}