From 22296b6cf897a88eefc41be655d7f1ef4c36e1cf Mon Sep 17 00:00:00 2001
From: Franciszek Stachura <fbstachura@gmail.com>
Date: Mon, 5 Aug 2024 15:02:43 +0200
Subject: [PATCH] Fix incorrectly issued 301 redirects on latest for project
 roots

This commit adds a small piece of Javascript code to force browsers to forget
about incorrectly issued 301 redirects from "latest" versions.
This code only runs for root project paths (i.e. `/linux/v6.10.2/source`, but
not `/linux/v6.10.2/source/arch`) - other links with "latest" will remain
broken for people who visited them (at least until they clear their cache).
---
 http/script.js        | 19 +++++++++++++++++++
 templates/layout.html |  2 +-
 2 files changed, 20 insertions(+), 1 deletion(-)

diff --git a/http/script.js b/http/script.js
index 337bcb6..984fd8f 100644
--- a/http/script.js
+++ b/http/script.js
@@ -162,4 +162,23 @@ window.requestAnimationFrame(offsetAnchor)
 // in case of slow rendering very long pages.
 window.onload = function () {
   window.requestAnimationFrame(offsetAnchor)
+
+  // fix incorrectly issued 301 redirect
+  // https://developer.mozilla.org/en-US/docs/Web/API/Request/cache
+  // https://developer.mozilla.org/en-US/docs/Web/API/Request/redirect
+  // TODO: remove after 10.2024
+  let path = location.pathname.split('/');
+  if (path.length == 4) {
+    path[2] = 'latest';
+    let newPath = path.join('/');
+    fetch(newPath, {
+        cache: 'reload',
+        redirect: 'manual',
+        // this is to make sure that varnish will cache the response,
+        // by default fetch sends no-cache in both headers if cache='reload'
+        headers: {'Cache-Control': 'max-age=86400', 'Pragma': ''}
+    })
+      .then(console.log)
+      .catch(console.error);
+  }
 }
diff --git a/templates/layout.html b/templates/layout.html
index af77b6e..670be27 100644
--- a/templates/layout.html
+++ b/templates/layout.html
@@ -44,7 +44,7 @@
                 <span class="poweredby">powered by <a target="_blank" href="https://github.com/bootlin/elixir">Elixir 2.2</a></span>
             </footer>
         </div>
-        <script src="/script.js?v=3"></script>
+        <script src="/script.js?v=4"></script>
         <script src="/dynamic-references.js?v=4"></script>
         <script src="/autocomplete.js" project="{{ current_project }}"></script>
     </body>