Drop missing files from the recent list when opening them fails (#2706)

* Drop missing files from the recent list when opening them fails

Fixes #2700

Co-Authored-By: Claude Haiku 5.5 <noreply@anthropic.com>
Co-Authored-By: Claude Sonnet 5.5 <noreply@anthropic.com>

* Keep a recent file whose existence can't be checked (CodeRabbit)

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

---------

Co-authored-by: Claude Haiku 5.5 <noreply@anthropic.com>
Co-authored-by: Brandon Thomas <echelon@gmail.com>

crates/ui-egui/src/lib.rs

@@ -570,7 +570,13 @@ impl CadApp {
     /// Add the files whose background read has finished; report the ones that failed as a failed
     /// OPEN is reported. Called every frame.
     pub fn finish_opening(&mut self) {
-        for (_, outcome) in self.opening.poll() {
+        for (path, outcome) in self.opening.poll() {
+            // A recent file that is gone can never be opened again: drop it from the list. A path
+            // whose existence can't be checked (a folder that denies access) stays.
+            if outcome.is_err() && matches!(path.try_exists(), Ok(false)) {
+                let path = path.to_string_lossy();
+                self.ui.recent_files.retain(|p| *p != path);
+            }
             let r = match outcome {
                 Ok(f) => self.session.finish_open(f).map_err(|e| e.to_string()),
                 Err(e) => Err(e),

crates/ui-egui/tests/recent_files.rs

@@ -135,3 +135,15 @@ fn start_page_lists_recent_files_and_opens_one_on_click() {
     assert_eq!(app.session.state().ok().and_then(|s| s.path.clone()), Some(plan.clone()));
     assert_eq!(app.ui.recent_files, [plan, section]);
 }
+
+#[test]
+fn a_recent_file_that_no_longer_exists_is_dropped_when_opening_it_fails() {
+    let (_dir, plan, _section) = drawings("missing");
+    let mut app = CadApp::new(Session::empty(), Services::default());
+    let gone = "/nonexistent/dir/gone.dxf".to_string();
+    app.ui.recent_files = vec![gone.clone(), plan.clone()];
+    let id = open_recent(&app).into_iter().find(|(l, _)| l == "gone.dxf").map(|(_, id)| id).unwrap_or_default();
+    menus::activate(&mut app, &id);
+    settle(&mut app);
+    assert_eq!(app.ui.recent_files, [plan], "the stale entry is removed, the others stay");
+}