Harden Typst wasm parser fallback against panics

src/lib/components/ConflictModal.svelte

@@ -110,7 +110,7 @@
             : 'border-[var(--color-line)] text-[var(--color-ink-muted)] hover:bg-[var(--color-surface-muted)]'}"
           onclick={() => (index = position)}
         >
-          {#if choices[position].includes("<<<<<<<")}
+          {#if choices[position]?.includes("<<<<<<<")}
             <Icon icon="ph:warning" class="text-[var(--color-danger)]" />
           {:else}
             <Icon icon="ph:check-circle" class="text-[var(--color-success)]" />

src/lib/components/Editor.svelte

@@ -70,6 +70,12 @@
 
   const isToml = $derived(filePath.toLowerCase().endsWith(".toml"));
 
+  function disableTypstLanguage() {
+    queueMicrotask(() => {
+      view?.dispatch({ effects: languageSlot.reconfigure([]) });
+    });
+  }
+
   function resilientSync(parser: any) {
     return StateField.define<null>({
       create: () => null,
@@ -78,7 +84,11 @@
           transaction.startState.facet(language) !==
           transaction.state.facet(language)
         ) {
+          try {
             parser.clearParser();
+          } catch {
+            disableTypstLanguage();
+          }
           return null;
         }
 
@@ -94,7 +104,13 @@
             for (const edit of edits.edits) parser.applyTreeEdit(edit);
           });
         } catch {
+          try {
             parser.clearParser();
+          } catch {
+            // The wasm parser instance panicked and is no longer usable.
+            // Drop syntax highlighting rather than crash on every keystroke.
+            disableTypstLanguage();
+          }
         }
 
         return null;

src/lib/ts/state.svelte.ts

@@ -688,7 +688,7 @@ async function tryOpenCollab(file: string, diskContent: string) {
   );
 
   const synced = await new Promise<boolean>((resolve) => {
-    session.provider.once("synced", (isSynced: boolean) => resolve(isSynced));
+    session.provider.once("sync", (isSynced: boolean) => resolve(isSynced));
   }).catch(() => false);
 
   if (app.activePath !== file) {