From 2f1193f8761f3b346c2ce7b273d6d64e5d72b5cd Mon Sep 17 00:00:00 2001
From: Jorge Manrubia <jorge@hey.com>
Date: Wed, 8 Nov 2023 09:09:36 +0100
Subject: [PATCH] Respect morphing and scroll preservation settings when
 handling form errors

Turbo will render 422 responses to allow handling form errors. A common scenario
in Rails is to render those setting the satus like:

```
render "edit", status: :unprocessable_entity
```

This change will consider such operations a "page refresh" and will also consider
the scroll directive.
---
 src/core/drive/navigator.js                |  4 +++-
 src/core/drive/page_view.js                |  2 +-
 src/tests/fixtures/page_refresh.html       |  7 +++++++
 src/tests/functional/page_refresh_tests.js | 17 +++++++++++++++--
 4 files changed, 26 insertions(+), 4 deletions(-)

diff --git a/src/core/drive/navigator.js b/src/core/drive/navigator.js
index 0d7259913..999d97817 100644
--- a/src/core/drive/navigator.js
+++ b/src/core/drive/navigator.js
@@ -99,7 +99,9 @@ export class Navigator {
       } else {
         await this.view.renderPage(snapshot, false, true, this.currentVisit)
       }
-      this.view.scrollToTop()
+      if(!snapshot.shouldPreserveScrollPosition) {
+        this.view.scrollToTop()
+      }
       this.view.clearSnapshotCache()
     }
   }
diff --git a/src/core/drive/page_view.js b/src/core/drive/page_view.js
index 6cf25dfd5..249b73efc 100644
--- a/src/core/drive/page_view.js
+++ b/src/core/drive/page_view.js
@@ -60,7 +60,7 @@ export class PageView extends View {
   }
 
   isPageRefresh(visit) {
-    return visit && this.lastRenderedLocation.href === visit.location.href
+    return !visit || this.lastRenderedLocation.href === visit.location.href
   }
 
   get snapshot() {
diff --git a/src/tests/fixtures/page_refresh.html b/src/tests/fixtures/page_refresh.html
index d8d948a63..ec28092a4 100644
--- a/src/tests/fixtures/page_refresh.html
+++ b/src/tests/fixtures/page_refresh.html
@@ -49,6 +49,13 @@ <h3>Element with Stimulus controller</h3>
       <input id="form-submit" type="submit" value="form[method=post]">
     </form>
 
+    <div id="reject">
+      <form class="unprocessable_entity" action="/__turbo/reject" method="post" style="margin-top:100vh">
+        <input type="hidden" name="status" value="422">
+        <input type="submit">
+      </form>
+    </div>
+
     <div id="container">
     </div>
   </body>
diff --git a/src/tests/functional/page_refresh_tests.js b/src/tests/functional/page_refresh_tests.js
index 272a34c09..70c798587 100644
--- a/src/tests/functional/page_refresh_tests.js
+++ b/src/tests/functional/page_refresh_tests.js
@@ -4,8 +4,9 @@ import {
   nextEventNamed,
   nextEventOnTarget,
   noNextEventOnTarget,
-  noNextEventNamed
+  noNextEventNamed, nextBody, hasSelector
 } from "../helpers/page"
+import { assert } from "chai"
 
 test("renders a page refresh with morphing", async ({ page }) => {
   await page.goto("/src/tests/fixtures/page_refresh.html")
@@ -53,7 +54,7 @@ test("don't refresh frames contained in [data-turbo-permanent] elements", async
   expect(await noNextEventOnTarget(page, "refresh-reload", "turbo:before-frame-morph")).toBeTruthy()
 })
 
-test("frames marked with refresh='morph' are excluded from full page morphing", async ({ page }) => {
+test("remote frames excluded from full page morphing", async ({ page }) => {
   await page.goto("/src/tests/fixtures/page_refresh.html")
 
   await page.evaluate(() => document.getElementById("remote-frame").setAttribute("data-modified", "true"))
@@ -126,6 +127,18 @@ test("it preserves data-turbo-permanent elements that don't match when their ids
   await expect(page.locator("#preserve-me")).toHaveText("Preserve me, I have a family!")
 })
 
+test("renders unprocessable entity responses with morphing", async ({ page }) => {
+  await page.goto("/src/tests/fixtures/page_refresh.html")
+
+  await page.click("#reject form.unprocessable_entity input[type=submit]")
+  await nextEventNamed(page, "turbo:render", { renderMethod: "morph" })
+  await nextBody(page)
+
+  const title = await page.locator("h1")
+  assert.equal(await title.textContent(), "Unprocessable Entity", "renders the response HTML")
+  assert.notOk(await hasSelector(page, "#frame form.reject"), "replaces entire page")
+})
+
 async function assertPageScroll(page, top, left) {
   const [scrollTop, scrollLeft] = await page.evaluate(() => {
     return [