bread-theme 0.2.8: fix live reload — watch the dir, not the file

The stylesheet is written with write-tmp-then-rename (atomic), which replaces the
inode. A monitor on the file itself caught the first replace then went deaf
(inotify reports DELETE_SELF and never re-arms), so `bread-theme reload` updated
the file but no running GUI ever recoloured. Monitor the parent directory and
filter for the stylesheet filename instead — that fires on every reload. Verified
against a real atomic-rename write (event arrives as Renamed with the new name in
other_file, so match both file and other_file).

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

bread-theme/src/gtk.rs

@@ -26,6 +26,33 @@ fn reload_app() {
     }
 }
 
+/// Watch the shared stylesheet for changes and run `reload` when it's rewritten.
+///
+/// `bread-theme` writes the file with write-tmp-then-rename (atomic), which
+/// *replaces the inode*. A monitor on the file itself dies after the first
+/// replace (inotify reports DELETE_SELF and never re-arms), so we monitor the
+/// parent *directory* and filter for the stylesheet's filename — that fires
+/// reliably on every reload. Returns the monitor (keep it alive to stay armed).
+fn watch_theme_file(reload: fn()) -> Option<gio::FileMonitor> {
+    let target = crate::shared_css_path();
+    let dir = target.parent()?;
+    // The dir must exist to be monitored; `bread-theme generate` makes it at
+    // login, but create it here too so a GUI started first still arms the watch.
+    let _ = std::fs::create_dir_all(dir);
+    let monitor = gio::File::for_path(dir)
+        .monitor_directory(gio::FileMonitorFlags::WATCH_MOVES, gio::Cancellable::NONE)
+        .ok()?;
+    monitor.connect_changed(move |_, file, other, _event| {
+        // The rename lands as an event whose file (or move destination) is the
+        // stylesheet. Match either to catch both CREATED/CHANGED and MOVED_IN.
+        let is_target = |f: &gio::File| f.path().as_deref() == Some(target.as_path());
+        if is_target(file) || other.is_some_and(is_target) {
+            reload();
+        }
+    });
+    Some(monitor)
+}
+
 /// Apply an app's *own* stylesheet and keep it live across palette changes.
 ///
 /// `build` is called now to produce the app-specific CSS, and again every time
@@ -47,11 +74,7 @@ pub fn apply_app_css<F: Fn() -> String + 'static>(build: F) {
         if cell.borrow().is_some() {
             return;
         }
-        let file = gio::File::for_path(crate::shared_css_path());
-        if let Ok(monitor) = file.monitor_file(gio::FileMonitorFlags::NONE, gio::Cancellable::NONE) {
-            monitor.connect_changed(|_, _, _, _| reload_app());
-            *cell.borrow_mut() = Some(monitor);
-        }
+        *cell.borrow_mut() = watch_theme_file(reload_app);
     });
 }
 
@@ -68,11 +91,7 @@ pub fn apply_shared() {
         if cell.borrow().is_some() {
             return;
         }
-        let file = gio::File::for_path(crate::shared_css_path());
-        if let Ok(monitor) = file.monitor_file(gio::FileMonitorFlags::NONE, gio::Cancellable::NONE) {
-            monitor.connect_changed(|_, _, _, _| reload_shared());
-            *cell.borrow_mut() = Some(monitor);
-        }
+        *cell.borrow_mut() = watch_theme_file(reload_shared);
     });
 }