a deploy must not break tabs that are already open

docs/CONTRIBUTING.md

@@ -21,8 +21,8 @@ Open `http://localhost:5173` in Chrome or Edge. Firefox and Safari work too, the
 - `src/lib/git` wraps isomorphic-git. `handle-fs.ts` is the file system adapter that lets it run on the project folder, `engine.ts` the operations, `errors.ts` turns its errors into something readable. The panel lives in `src/lib/ui/git`, one file per tab.
 - `src/lib/project` holds the open files, the project tree and everything the toolbar calls.
 - `src/lib/ui` are the Svelte components, `src/routes/editor` is the editor page itself.
-- `static/sw.js` is the service worker that resolves TeX Live files on demand: cache first, then the bundled subset, then the jsDelivr mirror, then the fallback server.
-- `static/texlive/cache` is the bundled package subset. If you change anything in there, bump `BUNDLE_VERSION` in `static/sw.js` and `WARMED_VERSION` in `src/lib/compiler/offline-cache.ts`, otherwise users keep the old files in their cache.
+- `src/service-worker.ts` is the service worker. It keeps every file of the current build in a cache of its own, so a page that was open before a deploy still gets its chunks, and it resolves TeX Live files on demand: cache first, then the bundled subset, then the jsDelivr mirror, then the fallback server.
+- `static/texlive/cache` is the bundled package subset. If you change anything in there, bump `BUNDLE_VERSION` in `src/service-worker.ts` and `WARMED_VERSION` in `src/lib/compiler/offline-cache.ts`, otherwise users keep the old files in their cache.
 - `static/swiftlatex` is the engine. It is a build artifact, not something to edit by hand.
 
 ## What helps most

src/lib/compiler/offline-cache.ts

@@ -6,7 +6,7 @@ import { base } from '$app/paths';
 // down (the cache writes compete with compile i/o otherwise).
 
 const FLAG = 'texbrain-texlive-warmed';
-// matches BUNDLE_VERSION in sw.js: when the bundle changes, the warm set
+// matches BUNDLE_VERSION in service-worker.ts: when the bundle changes, the warm set
 // is evicted and needs one fresh run
 const WARMED_VERSION = '4';
 const CONCURRENCY = 2;

src/routes/+layout.svelte

@@ -3,14 +3,25 @@
   import Toast from '$lib/ui/Toast.svelte';
   import { onMount } from 'svelte';
   import { browser } from '$app/environment';
+  import { beforeNavigate } from '$app/navigation';
+  import { updated } from '$app/state';
   import { preferences } from '$lib/stores/preferences';
   import type { Snippet } from 'svelte';
 
   let { children }: { children: Snippet } = $props();
 
+  // after a deploy the chunks this tab knows about are gone from the server.
+  // a full page load on the next navigation picks up the new build instead
+  // of failing on a missing file
+  beforeNavigate(({ willUnload, to }) => {
+    if (updated.current && !willUnload && to?.url) {
+      location.href = to.url.href;
+    }
+  });
+
   onMount(() => {
     if (browser && 'serviceWorker' in navigator) {
-      navigator.serviceWorker.register('/sw.js').catch(() => {});
+      navigator.serviceWorker.register('/service-worker.js').catch(() => {});
 
       // keep the service worker's texlive mirror config in sync
       const unsubscribe = preferences.subscribe((prefs) => {