Fix for SubmitEvent polyfill breaking requestSubmit() for newer Safari versions

src/polyfills/submit-event.ts

@@ -23,10 +23,14 @@ function clickCaptured(event: Event) {
   // Certain versions of Safari 15 have a bug where they won't
   // populate the submitter. This hurts TurboDrive's enable/disable detection.
   // See https://bugs.webkit.org/show_bug.cgi?id=229660
-  if ("SubmitEvent" in window && /Apple Computer/.test(navigator.vendor)) {
-    prototype = window.SubmitEvent.prototype
-  } else if ("SubmitEvent" in window) {
-    return // polyfill not needed
+  if ("SubmitEvent" in window) {
+    const prototypeOfSubmitEvent = window.SubmitEvent.prototype
+
+    if (/Apple Computer/.test(navigator.vendor) && !("submitter" in prototypeOfSubmitEvent)) {
+      prototype = prototypeOfSubmitEvent
+    } else {
+      return // polyfill not needed
+    }
   }
 
   addEventListener("click", clickCaptured, true)

src/tests/fixtures/form.html

@@ -312,6 +312,11 @@ <h2>Frame: Form</h2>
       <select id="external-select" form="form-with-external-inputs" name="greeting">
         <option selected>Hello from a replace Visit</option>
       </select>
+      <form id="form-with-buttons-triggered-by-js" action="/__turbo/redirect" data-turbo-frame="_top" method="post">
+        <input type="hidden" name="path" value="/src/tests/fixtures/one.html">
+        <button type="submit" formaction="/src/tests/fixtures/frames/hello.html" formmethod="get" id="button-triggered-by-js" data-turbo-action="replace" data-turbo-frame="hello">Navigate other Frame with GET</button>
+        <button type="button" onclick="this.form.requestSubmit(document.getElementById('button-triggered-by-js'))" id="request-submit-trigger">Trigger Navigate other Frame with GET</button>
+      </form>
     </turbo-frame>
     <a href="/src/tests/fixtures/frames/hello.html" data-turbo-method="get" id="link-method-outside-frame">Method link outside frame</a><br />
     <a href="/__turbo/messages?content=Link!&type=stream" data-turbo-method="post" id="stream-link-method-outside-frame">Stream link outside frame</a>

src/tests/functional/form_submission_tests.ts

@@ -234,6 +234,15 @@ test("test standard GET HTMLFormElement.requestSubmit() with Turbo Action", asyn
   assert.equal(getSearchParam(page.url(), "greeting"), "Hello from a replace Visit", "encodes <form> into request")
 })
 
+test("test GET HTMLFormElement.requestSubmit() triggered by javascript", async ({ page }) => {
+  await page.click("#request-submit-trigger")
+
+  await nextEventNamed(page, "turbo:load")
+
+  assert.notEqual(pathname(page.url()), "/src/tests/fixtures/one.html", "SubmitEvent was triggered without a submitter")
+  assert.equal(await page.textContent("#hello h2"), "Hello from a frame", "navigates #hello turbo frame")
+})
+
 test("test standard GET form submission with [data-turbo-stream] declared on the form", async ({ page }) => {
   await page.click("#standard-get-form-with-stream-opt-in-submit")